NEET Foundation

NEET Biology Chapter 3 Diversity In Living Organisms MCQs

Chapter 3 Diversity In Living Organisms Multiple Choice Question And Answers

Direction: Choose the correct option for each question. There is only one correct response for each question.

Question 1. Binomial nomenclature was given by

1. R. H. Whittaker
2. Linnaeus
3. Aristotle
4. Theophrastus

Answer. 2. Linnaeus

Question 2. The science of naming organism is called

1. identification
2. nomenclature
3. classification
4. taxonomy

Answer. 2. nomenclature

Question 3. The term biodiversity was coined by

1. Rosen
2. Linnnaeus
3. Darwin
4. Aristotle

Answer. 1. Rosen

Question 4. Which of the following categories contain least common features as compared to genus?

1. Genus
2. Division
3. Class
4. Family

Answer. 4. Family

NEET Biology Chapter 3 Diversity in Living Organisms MCQs

Read and Learn More NEET Foundation Multiple Choice Questions

Question 5. Taxon is the unit of

1. order
2. species
3. genus
4. taxonomy

Answer. 4. taxonomy

Question 6. Binomial nomenclature consists of two words

1. genus and species
2. order and family
3. family and genus
4. species and variety

Answer. 1. genus and species

Question 7. A plant body not differentiated into root, stem and leaves is termed as

1. thallus
2. mycelium
3. hyphae
4. herb

Answer. 1. thallus

Question 8. The phylum of sedentary animals is

1. Mollusca
2. Echinodermata
3. Porifera
4. Both (a) and (b)

Answer. 3. Porifera

Question 9. Tapeworms is a members of the phylum

1. Annelida
2. Porifera
3. Nematoda
4. Platyhelminthes

Answer. 4. Platyhelminthes

Question 10. True coelom appeared for the first time in

1. Mollusca
2. Nematoda
3. Annelida
4. Arthropoda

Answer. 3. Annelida

Question 11. Phylum Chordata is named after the occurrence of

1. notochord
2. dorsal hollow nerve cord.
3. occurrence of postnatal tail.
4. presence of gill slits.

Answer. 1. notochord

Question 12. Naked seeds are present in

1. Mango
2. Lemon
3. Pinus
4. Mustard

Answer. 3. Pinus

Question 13. The book System of Nature was written by

1. Linnaeus
2. Haeckel
3. Whittaker
4. Robert Brown

Answer. 1. Linnaeus

Question 14. The book Origin of Species was written by

1. Haeckel
2. Robert Brown
3. Darwin
4. Linnaeus

Answer. 3. Darwin

Question 15. Real organs are absent in

1. Mollusca
2. Cnidaria
3. Arthropoda
4. Echinodermata

Answer. 2. Cnidaria

Question 16. Two-chambered heart occurs in

1. crocodiles
2. amphibians
3. aves
4. fish

Answer. 4. fish

Question 17. Which of the following feature is not a characteristic of Protochordata?

1. Presence of notochord
2. Bilateral symmetry and coelom
3. Jointed leg
4. Presence of circulatory system

Answer. 3. Jointed leg

Question 18. The locomotory organs of Echinodermata are

1. parapodia
2. tube feet
3. muscular feet
4. jointed legs

Answer. 2. tube feet

NEET Biology Chapter 3 Diversity in Living Organisms MCQs

Question 19. Which one is a true fish?

1. Jelly fish
2. Star fish
3. Dogfish
4. Silverfish

Answer. 3. Dogfish

Question 20. Comb jellies belong to

1. Scyphozoa
2. Hydrozoa
3. Ctenophora
4. Rhyzopus

Answer. 3. Ctenophora

Question 21. Which of the following is triploid in nature in angiosperm?

1. Embryo
2. Endosperm
3. Cotyledons
4. Anther

Answer. 2. Endosperm

Question 22. Pick the odd one out.

1. Maize
2. Grass
3. Wheat
4. Mango

Answer. 4. Mango

Question 23. Which of the following is not an aquatic animal?

1. Filaria
2. Hydra
3. Jelly fish
4. Corals

Answer. 1. Filaria

Question 24. Differentiation in segmental fashion occurs in which of the following?

1. Starfish
2. Leech
3. Snails
4. Ascaris

Answer. 2. Leech

Question 25. Five-kingdom classification was given by

1. Morgan
2. Linnaeus
3. R.H.Whittaker
4. Haeckel

Answer. 3. R.H.Whittaker

NEET Foundation Biology Diversity in Living Organisms MCQs 

Question 26. Carl von Linnaeus was involved with which branch of science?

1. Morphology
2. Taxonomy
3. Physiology
4. Medicine

Answer. 2. Taxonomy

Question 27. Amphibians do not have which of the following?

1. Three chambered heart
2. Gills or lungs
3. Scales
4. Mucous gland

Answer. 3. Scales

Question 28. Skeleton is made entirely of cartilage in

1. Shark
2. Tuna
3. Rohu
4. None of these

Answer. 1. Shark

Question 29. Well-defined nucleus is absent in which of the following?

1. Diatoms
2. Algae
3. Yeast
4. Blue-green algae

Answer. 4. Blue-green algae

Question 30. Tissue level organization is found in which of the following?

1. Porifera
2. Coelenterata
3. Protozoa
4. Round worms

Answer. 2. Coelenterata

Question 31. In higher chordates, notochordis transformedinto

(1) Cranium

(2) Limbs

(3) Vertebral column

(4) Canal system

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 2. Only (2) and (3)

Question 32. Cnidaria is characterized by

(1) Nematoblasts

(2) Coelenteron

(3) Jointed legs

(4) Cellular level of organization

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 1. Only (1) and (2)

Question 33. Bilateral symmetry means_____________

(1) Limbs and organs are paired.

(2) Limbs and organs occur all around the central axis.

(3) Cephalization is present.

(4) Cephalization is absent.

Select the correct option:

1. Only (1) and (2)
2. Only (2) and (3)
3. Only (1) and (3)
4. Only (3) and (4)

Answer. 3. Only (1) and (3)

Question 34. The characteristic features of Bryophyta is_____

(1) Plant body is sporophytic.

(2) They are vascular plants.

(3) Plant body is gametophytic.

(4) They are non-vascular in nature.

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 3. Only (3) and (4)

NEET Foundation Biology Diversity in Living Organisms MCQs 

Question 35. Binomial nomenclature consists of two words

(1) Order

(2) Family

(3) Genus

(4) Species

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (3)
3. Only (1) and (4)
4. Only (3) and (4)

Answer. 4. Only (3) and (4)

Question 36. Characteristic features of Fungi are

(1) Presence of photosynthetic pigments.

(2) The cell wall is made of chitin.

(3) The cell wall is made up of cellulose.

(4) Absence of photosynthetic pigments.

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (4)
3. Only (1) and (4)
4. Only (3) and (4)

Answer. 2. Only (2) and (4)

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Question 37. Which among the following have open circulatory system?

(1) Arthropoda

(2) Mollusca

(3) Annelida

(4) Cnidaria

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 1. Only (1) and (2)

NEET Foundation Biology Diversity in Living Organisms MCQs 

Question 38. Organisms without nucleus and cell organelles belong to

(1) Fungi

(2) Protista

(3) Archaebacteria

(4) Cyanobacteria

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 3. Only (3) and (4)

Question 39. Which among the following has specialized tissue for conduction of water?

(1) Gymnospermae

(2) Bryophyta

(3) Thallophyta

(4) Pteridophyta

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 4. Only (1) and (4)

Question 40. Which among the following have scales?

(1) Amphibians

(2) Pisces

(3) Reptiles

(4) Mammals

Select the correct option.

1. Only (1) and (3)
2. Only (3) and (4)
3. Only (2) and (3)
4. Only (1) and (2)

Answer. 3. Only (2) and (3)

Question 41. The characteristic features of Aves are

(1) Mammary glands are absent.

(2) Mammary glands are present.

(3) Forelimbs are modified into wings.

(4) Wings are absent.

Select the correct option.

1. Only (1) and (2)
2. Only (1) and (3)
3. Only (2) and (3)
4. Only (2) and (4)

Answer. 2. Only (1) and (3)

NEET Chapter 3 Biology MCQs Diversity in Living Organisms 

Question 42. Bony fishes are characterized by _______

(1) Cartilaginous endoskeleton

(2) 5–7 pairs of gill slits

(3) Terminal positioned mouth

(4) 4 pairs of gill slits

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 3. Only (3) and (4)

Question 43. Annelids have ______________

(1) Unjointed appendages

(2) Closed circulatory system

(3) Jointed appendages

(4) Open circulatory system

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 1. Only (1) and (2)

Question 44. Reptilia are characterized by ____________

(1) Three-chambered heart

(2) Incompletely four-chambered heart

(3) Fertilization is external

(4) Fertilization is internal

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (4)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 2. Only (2) and (4)

NEET Chapter 3 Biology MCQs Diversity in Living Organisms 

Question 45. Male ascaris can be distinguished from female one by the______________

(1) Curved posterior

(2) Round shape end

(3) Presence of penial setae

(4) Straight posterior

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (4)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 1. Only (1) and (2)

Question 46. The lowest category of classification is

1. Phylum
2. Genus
3. Species
4. Family

Answer. 3. Species

Question 47. The mode of nutrition in most fungi is

1. Autotrophic
2. Saprophytic
3. Holozoic
4. Symbiotic

Answer. 2. Saprophytic

Question 48. In Whittaker’s system of classification, unicellular organisms are kept under

1. Monera
2. Fungi
3. Protista
4. Protozoa

Answer. 3. Protista

Question 49. Pinus is a ___________ plant.

1. Bryophytic
2. Gymnospermous
3. Pteridophytic
4. Angiospermous

Answer. 2. Gymnospermous

Question 50. Find out incorrect sentence

1. Protista includes unicelluar eukaryotic organisms.
2. Whittaker considered cell sturcture, mode and source of nutrition for classifying the organisms in five kingdoms.
3. Both Monera and Protista may be autotrophic and heterotrophic.
4. Monerans have well defined nucleus.

Answer. 4. Monerans have well defined nucleus.

Question 51. Which among the following has specialized tissue for conduction of water?

(1) Thallophyta

(2) Bryophyta

(3) Pteridophyta

(4) Gymnosperms

1. (1) and (2)
2. (2) and (3)
3. (3) and (4)
4. (1) and (4)

Answer. 3. (3) and (4)

Question 52. Which among the following produce seeds?

1. Thallophyta
2. Bryophyta
3. Pteridophyta
4. Gymnosperms

Answer. 4. Gymnosperms

NEET Chapter 3 Biology MCQs Diversity in Living Organisms 

Question 53. Organisms without nucleus and cell organelles belong to

(1) fungi

(2) protista

(3) cyanobacteria

(4) archaebacteria

1. (1) and (2)
2. (3) and (4)
3. (1) and (4)
4. (2) and (3)

Answer. 2. (3) and (4)

Question 54. Which of the following is not a criterion for classification of living organisms?

1. Body design of the organism
2. Ability to produce one’s own food
3. Membrane bound nucleus and cell organelles
4. Height to the plant

Answer. 4. Height to the plant

Question 55. The book System a Nature was written by

1. Linnaeus
2. Haeckel
3. Whittaker
4. Robert Brown

Answer. 1. Linnaeus

Question 56. Karl von Linne was involved with which branch of science?

1. Morphology
2. Taxonomy
3. Physiology
4. Medicine

Answer. 2. Taxonomy

Question 57. 5-kingdom classification was given by

1. Morgan
2. R. Whittaker
3. Linnaeus
4. Haeckel

Answer. 2. R. Whittaker

Question 58. Well defined nucleus is absent in

1. blue green algae
2. diatoms
3. algae
4. yeast

Answer. 1. blue green algae

NEET Chapter 3 Biology MCQs Diversity in Living Organisms 

Question 59. The ‘Origin of Species’ is written by

1. Linnaeus
2. Darwin
3. Haeckel
4. Whittaker

Answer. 2. Darwin

Question 60. The most simple and primitive plants are

1. bacteria
2. algae
3. protista
4. fungi

Answer. 2. algae

Question 61. Which of the following organism lacks chlorophyll?

1. Rhizopus
2. Cycas
3. Spirogyra
4. Wheat

Answer. 1. Rhizopus

Question 62. Prokaryotic organisms are found in kingdom

1. Protista
2. Fungi
3. Monera
4. Plantae

Answer. 3. Monera

Question 63. To which group of animals, the nematocysts are unique:

1. Cnidaria
2. Porifera
3. Platyhelminthes
4. Annelida

Answer. 1. Cnidaria

Diversity in Living Organisms MCQs for NEET Preparation 

Question 64. Tube-within-tube plain is shown by:

1. Coelenterates
2. Flatworms
3. Round worms
4. Sponges

Answer. 3. Round worms

Question 65. Excretory organs of annelids are:

1. Protonephridia
2. Nephridia
3. Green glands
4. Kidneys

Answer. 2. Nephridia

Question 66. Study of molluscs is called:

1. Malacology
2. Conchology
3. Mycology
4. Phycology

Answer. 1. Malacology

Question 67. Aristotle’s lantern is found in:

1. Star fish
2. Brittle star
3. Sea urchin
4. Sea cucumber

Answer. 3. Sea urchin

Question 68. Link between animal kingdom and plant kingdom is:

1. Euglena
2. Amoeba
3. Trypansoma
4. Paramecium

Answer. 1. Euglena

Question 69. Metameric segmentation first appeared in:

1. Platyhelminthes
2. Annelida
3. Cockroach
4. Arthropoda

Answer. 2. Annelida

Question 70. The following vertebrate respires by skin:

1. Fish
2. Frog
3. Crocodile
4. Whale

Answer. 2. Frog

Diversity in Living Organisms MCQs for NEET Preparation 

Question 71. True coelom is lined with:

1. Ectoderm
2. Endoderm
3. Mesoderm
4. Ectoderm and endoderm

Answer. 3. Mesoderm

Question 72. Excretory cells of platyhelminthes are:

1. Flame cells
2. Nephridia
3. Solenocytes
4. Both (a) and (c)

Answer. 4. Both (a) and (c)

Question 73. Green glands present in some arthropod help in:

1. Respiration
2. Digestion
3. Excretion
4. None of these

Answer. 3. Excretion

Diversity in Living Organisms MCQs for NEET Preparation 

Question 74. Which of the following classes has largest number of animals?

1. Pisces
2. Reptilia
3. Mammalia
4. Insecta

Answer. 4. Insecta

Question 75. An open circulatory system occurs in the:

1. Reptiles
2. Birds
3. Insects
4. Annelids

Answer. 3. Insects

Question 76. In Panthera pardus, the genus name is

1. Pardus
2. Panthera
3. None of these
4. Both Panthera and pardus

Answer. 2. Panthera

Question 77. Name the field of biology that deals with the identification, nomenclature and classification of organisms.

1. Systematics
2. Biogeography
3. Taxonomy
4. Vernacular science

Answer. 3. Taxonomy

Question 78. The naming system where every organism’s scientific names consists of two names is called

1. binomial nomenclature
2. binary nomenclature
3. bilateral nomenclature
4. coded nomenclature

Answer. 1. binomial nomenclature

Question 79. ______ is the study of evidences of the past life in the form of fossils.

1. Taxonomy
2. Classification
3. Palaeontology
4. Systematics

Answer. 3. Palaeontology

NEET Biology Diversity in Living Organisms Practice Questions

Question 80. Which theory states that organisms with different variant forms leave different numbers of offspring to future generations?

1. Perpetual change
2. Common descent
3. Graduation
4. Natural selection

Answer. 4. Natural selection

Question 81. Which theory states that the large differences in anatomical characteristics that make different species originate through the accumulation of many small incremental changes over long duration of time?

1. Perpetual change
2. Common descent
3. Graduation
4. Natural selection

Answer. 3. Graduation

Question 82. _______ includes all organisms who share a set of distinguishing common characters.

1. Order
2. Phylum
3. Kingdom
4. Family

Answer. 3. Kingdom

Question 83. Which of the following archaea favour extremely hot and acidic environments like hot springs?

1. Methanogens
2. Thermoacidophiles
3. Halophiles
4. Eubacteria

Answer. 1. Methanogens

Question 84. Which of the following archaea grow in very salty environments?

1. Methanogens
2. Thermoacidophiles
3. Halophiles
4. Eubacteria

Answer. 3. Halophiles

Question 85. Blue-green algae is also known as

1. Actinomycetes
2. Enterobacteria
3. Spirochaetes
4. Cyanobacteria

Answer. 2. Enterobacteria

Question 86. In which of the following, blue-green algae and fungi live in symbiotic relationship?

1. Rhizopoda
2. Lichens
3. Protista
4. Protozoa

Answer. 3. Protista

Question 87. Which of the following lack locomotory organs?

1. Sporozoa
2. Ciliata
3. Mastigophora
4. Sarcodina

Answer. 4. Sarcodina

NEET Biology Diversity in Living Organisms Practice Questions

Question 88. The mode of nutrition in fungi is

1. only saprotrophic.
2. saprotrophic or parasitic.
3. only parasitic.
4. none of above

Answer. 2. saprotrophic or parasitic.

Question 89. Which of the following is not possessed by bacteria?

1. Membrane bound organelles
2. Nucleus
3. Nucleolus
4. All of these

Answer. 4. All of these

Question 90. Which sub-group in plant kingdom produces flowers?

1. Angiosperms
2. Fungi
3. Mosses
4. Ferns

Answer. 1. Angiosperms

Question 91. What does a bacteria lack?

1. Endoplasmic reticulum
2. DNA.
3. Cell wall
4. Cytoplasm

Answer. 1. DNA.

Question 92. What is the mode of nutrition in bacteria?

1. Autotrophic
2. Heterotrophic
3. Autotrophic and heterotrophic
4. None of these

Answer. 3. Autotrophic and heterotrophic

Question 93. In algae, asexual reproduction usually takes place by

1. spores
2. gametes
3. single-celled sex organs
4. embryo

Answer. 2. gametes

Question 94. Pteridophytes have sex organs that are

1. unicellular only.
2. multicellular without any jacket.
3. multicellular and jacketed by sterile cells.
4. bicellular

Answer. 3. multicellular and jacketed by sterile cells.

Question 95. Which of the following are known as the ‘Amphibians of Plant Kingdom’?

1. Pteridophytes
2. Bryophytes
3. Gymnosperms
4. Green algae

Answer. 4. Green algae

Question 96. Name the most primitive and simple seed plants.

1. Pteridophytes
2. Bryophytes
3. Gymnosperms
4. Angiosperms

Answer. 2. Bryophytes

NEET Biology Diversity in Living Organisms Practice Questions

Question 97. In which of the following the reproductive organs are hidden?

1. Cryptogamae
2. Phanerogamae
3. Gymnosperms
4. Angiosperms

Answer. 1. Cryptogamae

Question 98. Choose the vascular plants out of these.

1. Mosses
2. Liverworts
3. Hornworts
4. Ferns

Answer. 4. Ferns

Question 99. Which of the these are found filamentous?

1. Spirogyra
2. Euglena
3. Chlamydomonas
4. Amoeba

Answer. 1. Spirogyra

Question 100. Which of the following does a bacteria lack?

1. Endoplasmic reticulum
2. DNA
3. Cell wall
4. Cytoplasm

Answer. 1. Endoplasmic reticulum

Question 101. What is the phylum of octopus?

1. Arthropoda
2. Mollusca
3. Annelida
4. cnidarian

Answer. 2. Mollusca

NEET Biology Diversity in Living Organisms Practice Questions

Question 102. Gametophytic and sporophytic generations are seen in the life history of which of the following?

1. Fungi
2. Algae
3. Ferns
4. Diatoms

Answer. 3. Ferns

Chapter 2 Tissues

Tissue

It is evidently known that multicellular organisms are made up of trillions of cells, but each and every cell performs specific functions.  A group of cells that are similar in structure and which performs a  specific function are described as tissues. Owing to this, a specific  function is performed by a group of cells at a particular site in the  organism’s body.

Hence, different functions are performed by different  groups of cells in an organism, and this is called division of labour in  organisms.

Division of labour in organisms enables a smooth and efficient functioning in the body for better survival and also different functions  can be performed at the same time. For example, in human body,  several processes occur such as digestion. A  tissue is a group of  cells having similar structure to perform a specific function.

In  a  particular tissue, all the cells have a common origin. For example,  in human beings, nervous tissue that is present in brain, spinal cord  and nerves has nerve cells or neurons having the same basic structure  and function. Both plants and animals possess tissues, but these are  different from each other. The study of tissues is known as Histology.

Chapter 2 Tissues Are Plants and Animals Made of the Same Types of Tissues

The world we live is diverse and complex. Each form is different from other to a lesser or greater extent. When we compare the structure and functions of plant and animal tissues there are noticeable differences between them. Plants are fixed and they do not move. Plant tissues provide structural strength.

Read and Learn More: NEET Foundation Notes

Animals move around and consume more energy as compared to plants. The growth in plants is limited to certain regions also some plant tissues divide throughout their life. Based on dividing capacity of the tissues, plant tissues are classified into growing or permanent tissue.

Types Of Tissue

The cell differentiation and growth in animal tissue is more uniform and there is no clear distinction of dividing and non-dividing cells. Tissues get organized to form organs and organs into organ systems. The science of cells is called cytology, and science of organs is called organology. The embryonic derivation of tissues is called histogenesis.

Tissue Structure

Chapter 2 Tissues Plant Tissues

Plants are multicellular organisms made up of trillions of cells which cluster together to perform a specific function. Plant tissues provide mechanical strength to internal as well as external organs. They provide elasticity and flexibility to the plant organs; for example, the leaves, stems and branches of trees can bend without causing any damage to the plant body.

They also help in transportation of materials across the plant body and prevents loss of water. They undergo division to help the plants to grow both in length and girth. The plant tissues are involved in many metabolic processes, such as photosynthesis, respiration, etc.

Plant tissues can be categorized into two types – (1) Meristematic, (2) Permanent

Meristematic Tissues (Meristems)

Meristematic tissue or simple meristems is a group of dividing cells that has the capacity to divide and re-divide and help in the growth of plants. Nageli (1858) gave the term ‘meristem’. Meristems are found in the apices of stem and root, leaf primordia, vascular cambium, cork cambium, etc.

Characteristics of Meristematic Tissue

• The cells are oval, rounded or polygonal in shape.
• The cells are living with thin cellulose walls and without any intercellular spaces.
• The cells are rich in cytoplasm due to cell division which constantly produce a lot of biomolecules.
• The cells are diploid and undergo mitosis.
• The cells do not contain reserve food materials, endoplasmic reticulum and plastids. Hence, the cells lack vacuoles.

Types of Meristems

Meristems or meristematic tissues are categorized into many types based on the following criteria.

• Classification based on origin and development
• Classification based on position
• Classification based on function
• Classification based on plane of division

• Classification based on origin and development: Meristems can be categorized into three types.
• • Promeristem or primordial meristem: It is a group of young meristematic cells present in the growing organ, such as the tips of stem and root. It is the early embryonic meristem that gives rise to other advanced meristems. It further divides to ­produce primary meristem.
  • Primary meristem: It is derived from promeristem and is found below the promeristem at shoot and root apices. These cells divide to produce permanent tissues, such as apical meristem, intercalary meristem and intrafascicular cambium.
  • Secondary meristem: It is derived from primary permanent tissues that have the capacity to divide. For example, cork cambium, root cambium and interfascicular ­cambium of stem.

• Classification based on position: Meristems can be ­categorized to three types:
• • Apical meristem: It is found at the apices or tips (i.e., growing points) of root and stem (shoot) and brings about an increase in length. It includes promeristem and as well as primary meristem. Many theories have been proposed to explain the activity of apical meristem.
  • Apical cell theory proposes that a single apical cell is the structural and functional unit of apical meristem that controls the whole process of apical growth. This type of organization is found only in cryptogams.
  • Intercalary meristem: This meristematic tissue is found between the regions of permanent tissues. It is considered as a part of primary meristem that has detached owing to the formation of intermediate permanent tissues. It is located either at the base of leaf, for example, Pinus or at the base of internodes, for example, grasses.
  • Lateral meristem: This meristem is arranged parallel to the sides of origin and normally divides periclinally or radially and produces secondary permanent ­tissues. This meristem helps in increasing the thickness of the plant and its parts.

• Classification based on function: Meristems are classified into three types.
• • Protoderm meristem: This is the outermost layer of the young growing region that develops to give rise to epidermal tissue system.
  • Procambium meristem: This consists of narrow, elongated, prosenchymatous, meristematic cells producing the vascular tissues system.

• • Ground meristem: This consists of large, thick-walled cells that gives rise to ground tissue system, which includes hypodermis, cortex and pith.
• Classification based on plane of divisions: Meristems are categorized into three types.
  • Mass meristem: The cell divisions occur in all planes resulting in the increase of volume. It can be found in meristems of cortex and pith.
  • Rib or file meristem: The cells divide only on one plane, for example, formation of ­filaments in algae.
  • Plate meristem: These cells divide in two planes resulting to an increase in the area of an organ, for example, leaf formation.

Chapter 2 Tissues Permanent Tissues

Permanent tissues are those tissues whose cells have lost the power of division or ability to multiply. The process by which the cells derived from meristematic tissue attain a permanent shape, size and function is known as differentiation. Hence, the cells of meristematic tissue differentiate to form cells of permanent tissues.

They are of various sizes, shape and other characteristic to make them suitable for different functions. Permanent tissues are classified into two main types, such as simple and complex permanent tissues.

Simple Permanent Tissues

A simple tissue is composed of one type of cells forming a uniform mass. Based on their functions, they are classified into three types—(i) Parenchyma; (2) Collenchyma and (3) Sclerenchyma

• Parenchyma: Parenchyma forms the bulk of the plant body and is found in the cortex of root, ground tissue in stems and mesophyll of leaves. The cells are isodiametric, i.e., equally expanded on all sides. The shape of the cells may be oval, round, polygonal or elongated.
  The cells consist of nucleus, and so are living in nature. The thin cell walls are made up of cellulose. The cell has dense cytoplasm with a single large vacuole. Intercellular air spaces are present.

• • Location of parenchymatous tissue: Parenchyma tissue is found in soft parts of stems and roots of the plant and forms the bulk tissue of the plant body.
  • Functions of parenchymatous tissue
    • The main function of parenchyma is to store and assimilate food.
    • Provides mechanical strength by maintaining turgidity.
    • Manufactures food if chlorophyll is present.
    • Stores waste material such as tannins, gum, crystals and resins.
  • Types of parenchymatous tissue: These are mainly of four types.

Functions and locations of parenchyma cells

• Collenchyma: Collenchyma is composed of elongated cells with irregularly thickened walls, having deposition of extra cellulose at the corners of the cells. The intercellular spaces are usually absent . The cells are usually living and have only a thick primary cell made up of cellulose and pectin. The thickness of cell wall is strongly influenced by mechanical stress upon the plant. For example, the cell walls of collenchyma in wind-exposed plants are 40–100% thicker as compared to those plants inhabiting in the less windy area.

• • Location of collenchyma: Found in leaf and below the outer protective layer of stems and leaves.
  • Functions of collenchyma
    • Provides structural support, specifically in growing stems and leaves.
    • Sometimes collenchyma consists of chloroplasts, which then manufactures sugar and starch.
    • Provides flexibility and tensile strength to the branches and facilitates easy bending of the plant.
  • Types of collenchyma: There are three main types of collenchyma.

Structure and location of collenchyma cells

Human Tissue

• Sclerenchyma: Sclerenchyma cells are dead cells that are devoid of cytoplasm. The cell walls are very thick made up of lignin. Due to the presence of excessing thickening of a sclerenchyma cell wall, its cell cavity becomes almost absent. A visible middle lamella is present between two sclerenchymatous cells.
• • Location: Sclerenchyma is found in stems (around the vascular bundles), roots, veins of leaves, hard coverings of seeds and nuts.
  • Function: Sclerenchyma tissue provides strength and mechanical support to various parts of the plant.
  • Types of sclerenchyma: The sclerenchyma is of two types and they are fibres and sclereids.
    • Fibres: They are pointed, needle-like structures. The cell walls are mainly composed of cellulose. Fibres generally originate from meristems. These are produced mainly in cambium and procambium. The fibres are generally associated with the xylem and phloem of the vascular bundles. The fibres of the xylem are lignified, whereas those of the phloem are cellulosic. Fibres that do not belong to the xylem are called bast (outside the ring of cambium). For example such as jute and coir (husk of coconut).
    • Sclereids: Sclereids are a reduced form of sclerenchyma cells with highly thickened and lignified walls. They are small bundles of sclerenchyma tissue in plants forming durable layers. The cells may be isodiametric, prosenchymatous, forked or elaborately branched. These can be grouped into bundles and it can form complete tubes located at the periphery or can occur as single cells or small groups of cells within parenchyma, for example such as hard grit of pear fruit. These structures are used to protect other cells.

Complex Permanent Tissues

The complex permanent tissues are composed of more than one type of cells that have a common origin and coordinate to perform a similar function. Complex tissue is responsible for the conduction of substances through the plants. Therefore, this tissue is called vascular tissue or conducting tissue.

These tissues are involved in the transport of water, mineral salts (nutrients) and food material. The complex permanent tissues are of two types, namely xylem or wood and phloem or bast. Usually, in higher plants, xylem and phloem occurs together in the roots, stems and leaves and they are called vascular bundles.

For the growth of tree, it is essential that new vessels within the stem should be formed, which is done by the vascular cambium. The vascular cambium is highly active during summer and spring seasons, generating a lighter band made of large diameter vessels.

During winter season, small diameter vessels and a darker band appears around the previous lighter band. Therefore, two rings are made per year, one of which is lighter and the other of which is darker. By counting these pairs directly, the age of the tree can be estimated.

Xylem

Xylem cells are thick-walled. They consists of cells (or ‘elements’) of four different kinds.

• Tracheids: These are non-living elongated cells with tapering ends. In these, the water passes from cell to cell through the pits.
• Vessels: These are shorter and wider than tracheids. They are non-living cylindrical tube-like cells. Vessels are made up of lignin. These are very long tubular structures formed by a row of cells placed end to end. The transverse walls between the vessel elements are partially or wholly dissolved to form continuous channels or water-pipes.
• Xylem parenchyma: Contains living cells. It stores food and helps in lateral conduction of water.
• Xylem sclerenchyma: They are non-living, thick-walled cells. It provides mechanical strength to the plant body.

Functions of Xylem

• Its main function is to carry water and mineral salts upward from the root to different parts of stem.
• It also provides mechanical strength to the plant body.

Phloem

Phloem consists of tubes but do not provide mechanical ­support. Phloem consists of four types of cells or elements as discussed below.

• Sieve tubes: These are slender, tube-like structures that consist of elongated thin-walled cells, placed end to end. The end walls of these cells are perforated by several pores and are known as sieve plates. The nucleus of the sieve cell degenerates at maturity, but cytoplasm still remains in the mature cell.
• Companion cells: These are smallthin-walled cells consisting of dense and very ­active cytoplasm with large elongated nucleus. These are ­connected to the sieve tube with several plasmodesmata. Companion cells consists of additional mitochondria and chloroplasts.
• Phloem parenchyma: These are thin-walled, living cells of ­parenchyma of phloem. They help in storage and slow lateral conduction of food.
• Phloem fibres or bast fibres: These are thickwalled, elongated spindle-shaped dead cells that possess narrow lumen. They provide mechanical strength to the tissue.

Functions of Phloem

Phloem helps in transporting photosynthetically prepared food materials from the leaves to the storage organs, from where these are supplied to the growing regions of the plant body.

Characteristics of Plant Tissue Systems

The structural and functional tissue systems of plants. The tissues of a plant are organized into three systems: the dermal tissue system, the ground tissue system, and the vascular tissue system and discussed below in Table 2.3.

• Dermal tissue covers the outer surface of the stem. It provides protection to the plant and it also helps in gaseous exchange.
• Ground tissue usually consists mainly of parenchyma cells and it surrounds the vascular tissue. It gets involved in photosynthesis sometimes.
• Vascular tissue provides long distance transport and mechanical support.

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Characteristics of plant tissue system

Chapter 2 Tissues Animal Tissues

Depending on the location and functions of the tissues in the human body, animal tissues are classified into four main types and they are listed below.

• Epithelial tissue
• Muscle or muscular tissue
• Connective tissue
• Nervous tissue

Epithelial Tissue (Epithelium)

Epithelial tissue is one of the simplest tissues, whose main function is to protect the animal body. In this tissue, the cells are tightly packed and form a continuous sheet. Cells of epithelium consist of no intercellular matrix. The epithelial tissue covers most of the organs and cavities within the animal body.

It also acts a barrier by keeping different organ systems separated. For instance, the skin and lining of buccal cavity, blood vessels, alveoli of lungs, kidney tubules and many others are made up of epithelial tissue. Beneath the epithelial cells is a non-cellular basement membrane that contains a special form of matrix protein known as collagen.

Functions of Epithelial Tissue

• The epithelial cells form the outer layer of the skin and protect the underlying cells from drying, injury and other chemical and physical effects.
• The epithelial cells form the lining of mouth and alimentary canal to protect these organs.
• The epithelial tissues help in the absorption of water and nutrients.
• The epithelial tissues help in the elimination of waste material.
• Some epithelial tissues secrete numerous substances like sweat, saliva, enzymes, etc.

Types of Epithelial Tissue

Epithelial tissue is a protective, excretory and sensory in function. Based on the shape and function of the cells, the epithelial tissues are categorized into five types as listed below.

• Squamous epithelium
• Cuboidal epithelium
• Columnar epithelium
• Glandular epithelium
• Ciliated epithelium

 

• Squamous epithelium: It is composed of thin, flat, irregular-shaped cells that fit together to form a compact tissue. Squamous epithelium is also called tessellated and pavement epithelium as it appears like floor tiles.
• • Stratified keratinized squamous epithelium: This tissue is found in skin and covers the external dry surface of the skin. Deeper layers of the tissue are composed of cuboidal cells that become polygonal and finally flattened (‘squamous’) towards the free surface. The flattened cells of superficial layer consist of a fibrous protein, the keratin, and become dead cells. Horny, scaly remnants of dead squamous cells, finally flakes away. This tissue is water-proof and highly resistant to mechanical injury.

• • Location: Squamous epithelium forms the delicate lining of cavities (mouth, oesophagus, nose, pericardium, alveoli, etc.) and of blood vessels and covering of the tongue and skin.
  • Functions
    • This tissue protects the underlying parts of body from mechanical injury, invasion of germs and chemicals and drying.
    • It also forms a selectively permeable lining through which filtration takes place.
• Cuboidal epithelium: This epithelium consists of cube-like (‘cuboidal’) cells that appear as square shaped in cross section but the free surface looks hexagonal.
  • Location: The cuboidal epithelium is found in kidney tubules, thyroid vesicles and in glands, such as salivary glands, sweat glands and exocrine glands. This epithelium forms germinal ­epithelium of gonads (testes and ovaries).
  • Functions: Cuboidal epithelium helps in absorption, ­excretion and secretion, and also provides mechanical support.

• Columnar epithelium: This epithelium is composed of the cells that are taller than broader and looks like pillars. The nuclei are present at the base and sometimes the free ends of cells have a brush border consisting of microvilli.
• • Location: The columnar epithelium forms the lining of stomach, small intestine and colon forming mucous membrane. It also lines the gall bladder, oviducts and facilitates movement across the cells.
  • Functions: It helps in the absorption (for example, stomach, intestine) and secretion (for example, mucous by goblet cells).

• Glandular epithelium: This epithelium consists of specialized cells that ­secrete bodily products and are called glands. Glands are of two types, such as endocrine and exocrine.
  Exocrine glands are generally the glands associated with the term ‘glandular ­epithelium’. These glands are of two types based on the morphology and they are unicellular glands and multicellular glands.
• Ciliated epithelium: This epithelium is composed of cuboidal or columnar cells having a free border that bear thread-like cytoplasmic outgrowths known as cilia.
• • Location: It occurs in the sperm ducts and lines the trachea (wind pipe), bronchi (lungs), kidney tubules and oviducts (Fallopian tubes).
  • Functions: The rhythmic, concerted beating of the cilia helps in the movement of solid particles in one direction through the ducts.

Chapter 2 Tissues Muscle or Muscular Tissue

The muscle tissues of the body form the contractile tissue and consist of muscle cells. Muscle cells are elongated and large-sized, and hence, they are also called muscle fibres. In muscle cells, the contractile proteins are present that help in the movements of the body or limbs through contraction and relaxation.

Typically, the muscle cells are arranged in parallel arrangement permitting them to work together effectively. Muscles help in body movements (local and gross). Major movements of the body rely on the action of skeletal muscles which are connected to bones. Based on their location, structure and function, muscles are of three types, such as striated muscles, smooth muscles and cardiac muscles.

Striated muscles: The entire muscle fibres show ­alternate dark and light stripes or bands or striations, they are also known as striped muscles. As they are attached to the bones and are responsible for body movements, they are also called skeletal muscles. Since these muscles work ­according to our will, they are also called voluntary muscles.

The striated muscle cells are elongated, non-tapering, cylindrical, unbranched and multinucleate cells. Each muscle cell is enclosed in a thin and distinct plasma membrane known as sarcolemma. In the sarcoplasm (cytoplasm) of the muscle cell are embedded numerous contractile elements known as sarcostyles or myofibrils.

Striated muscles are found in the muscles of limbs, body wall, face, neck, etc. Striated muscles found in tongue, pharynx, diaphragm and upper part of oesophagus are known as visceral striated muscles.

Functions of Striated Muscles

• These muscles undergo rapid contraction and can get tired and may need rest.
• These muscles provide the force for locomotion and all other voluntary movements of the body.

Smooth muscles: Smooth muscles are present as bundles or sheets of elongated fusiform or spindle-shaped cells or fibres. These are held together by loose connective tissue. Each muscle cell is covered by a plasma membrane. A single centrally ­located nucleus is present in the cytoplasm or sarcoplasm. Myofibrils run longitudinally throughout the cell. As these myofibrils are devoid of any bands or stripes or striations, these are known as smooth or unstriated ­muscles.

Smooth muscles are located in the walls of the hollow visceral organs except that of the heart, and hence, they are called visceral muscles. These muscles are found in the wall of alimentary canal and internal organs, ducts of glands, urogenital ducts and blood vessels. Smooth muscles are present in stomach, intestine, ureter, bronchi, iris of eye, etc.

Functions of Smooth Muscles

• Smooth muscles are also called involuntary muscles, as they do not work according to our will. For example, movement of food in the alimentary canal, opening and closing of tubes are involuntary movements.
• Smooth muscle contracts slowly but can remain contracted for long duration. Due to this characteristic, smooth muscles cause peristaltic movements in the tubes. Peristaltic movements are the rhythmic progressive waves of muscular contraction and relaxation. These movements happen in the gastrointestinal tract and male genital tract.
• In few organs, the smooth muscles contract throughout the organ to produce extrusive movements as in the urinary bladder, the gall bladder and the uterus.

Cardiac muscles: Cardiac muscles consist of branched fibres and these branches join to form a network. Each fibre or cell is enclosed in sarcolemma, sarcoplasm with longitudinal myofibrils and a centrally located nucleus. The intercellular spaces of ­cardiac muscles are filled with plenty of loose connective tissue provided by blood capillaries.

Cardiac muscles show stripes of light and dark bands. Also, these muscle fibres show densely stained crossbands known as intercalated impulse. These are zones of interdigitations of plasma membranes consisting of adjacent muscle cells or fibres. Cardiac muscles are found in the walls of the heart.

Cardiac muscles have excellent blood supply and are specialized to avoid becoming fatigued. Since asphyxiation can result in death within few minutes, cardiac muscles must be able to fulfil their duty transporting oxygen in blood haemoglobin. Cardiac muscles possess mitochondria that help with energy production in rhythmic capacity, even at high force when required.

Functions of Cardiac muscles

• Cardiac muscles contract and relax speedily, rhythmically and without getting tired throughout the life of a human.
• The contraction and relaxation of the heart muscles facilitate the pumping and distribution of blood to all parts of the body.

Chapter 2 Tissues Connective Tissue

The connective tissue is the most abundant tissue found in human body and it helps to connect and anchor various body organs. These tissues can connect bones to each other, muscles to bones, bind tissues and can also provide support to various other body parts by building a packing around the organs.

The packing would prevent the organs from getting displaced by body movements. Hence, the main functions of connective tissue are binding, supporting and packing together various organs of the body.

The tissue consists of three components, such as (a)  non-living intercellular substance called ground substance, (b) fibres made up of proteins and (c) living cells. Ground substance and fibres together form the extracellular matrix. Fibres are of three types such as and they are listed below.

• White fibres are inelastic, unbranched, made up of collagen fibres and most abundant in nature.
• Yellow fibres are elastic, branched and made up of protein elastin.
• Reticular fibres are inelastic, straight and made up of protein reticulin.

The cells of connective tissue are living, loosely spaced and few in number. Homogeneous, gel-like intercellular substance known as matrix forms the main bulk of the connective tissue. Therefore, the space between the cells is filled with a ­non-living matrix that may be solid as in bone and cartilage and may be fluid as in the blood.

Connective tissues are classified into four types and they are as follows.

• Loose connective tissue
• Dense connective tissue
• Specialized connective tissue
• Fluid connective tissue

Loose Connective Tissue

Loose and cellular connective tissue, whose matrix consists of two types of fibres are – (1) Areolar connective tissue, (2) Adipose connective tissue.

Areolar connective tissue: Areolar tissue is the simplest and most widely distributed connective tissue. It joins skin to muscles, fills spaces inside organs and is found around muscles, blood vessels and nerves.

Functions of Areolar Tissue

• Behaves as a supporting and packing tissue between organs lying in the body cavity. In this tissue, the matrix is important in diffusion of oxygen and nutrients from small blood vessels.
• Helps in the repairment of injured tissues after an injury.
• Helps in combating foreign toxins.
• It cements skin to underlying muscles.

Adipose connective tissue: Adipose tissue is an aggregation of fat cells called adipocytes.

Each fat cell is rounded or oval in shape and consists of a large droplet of fat that fills it.

The fat cells are arranged into lobules separated by partitions of collagen and elastin fibres, which carry blood vessels of lobules. Adipose tissue is found below the skin between the internal organs and in yellow bone marrow.

Functions of Adipose Tissue

• Adipose tissue is a reservoir for fats.
• Provides shape to the limbs and the body.
• Keeps visceral organs in position, and forms shock-absorbing cushions around kidneys and eye balls.

Dense Regular Connective Tissue

It consists of ordered and densely packed ­collection of fibres and cells. This tissue is mainly present in the tendons and ligaments and aponeurosis.

• Tendons: A tendon is a white fibrous tissue that has great strength but restricted flexibility. It is composed of parallel bundles of collagen fibres and between these fibres, the rows of fibroblasts called tendinocytes are present. Collagen fibres are bounded by areolar connective tissue. This tissue helps in the movement of bones.
• Ligaments: These are elastic structures that connect bones to bones. In ligament, some elastic and many collagen fibres are bound together by areolar connective tissue. ­Fibroblasts are compressed in between regular rows of fibres. Ligament strengthens the joint and allows normal movement but prevents over-flexing. By excessive pulling of ligaments, sprain is caused.
• Apneuroses: These are broad sheets of dense, fibrous, collagenous connective tissues that cover, invest and form the terminations and attachments of several muscles.

Special Connective Tissues

This tissue forms the endoskeleton of the organisms. They form the rigid framework which supports the body and provides protection of all vital organisms. Depending on the composition and characteristic, this tissue is classified into two types—cartilage and bone.

Cartilage: The cartilage is a connective tissue that is compact and less vascular. Its extensive matrix consists of proteins and is somewhat hardened by calcium salts. Its matrix is produced and maintained by the chondrocytes. The matrix is solid and firm but slightly elastic, which gives it a flexible nature.

The matrix of cartilage has a delicate network of collagen fibres and living cells called ­chondrocytes. There are three cartilages in human body, such as hyaline, fibrous and elastic. Cartilage is found in ear pinna, nose tip, epiglottis, intervertebral discs, end of long bones, lower ends of ribs and rings of trachea (wind pipe). The comparative study of three types of cartilage are discussed below in.

Characteristics of three types of cartilage

Functions of Cartilage

• It gives support and flexibility to the body organs.
• It makes the surface at joints smooth.

Bone: Bone is a very strong and non-flexible connective tissue. It is porous, highly vascular, mineralized, hard and rigid. Its matrix consists of proteins (for example, osteonectin, osteocalcin, proteoglycan and collagen). The matrix of bone consists of salts of calcium and magnesium like phosphates and carbonates of calcium and magnesium (for example, hydroxyapatite).

These minerals impart hardness to the bones. The matrix of the bone is in the form of thin concentric rings known as lamellae. Bone cells or osteoblasts or osteocytes are present between the lamellae in fluid-filled spaces called lacunae.

All lacunae of the bone communicate with each other by a network of fine canals called canaliculi. Each canaliculus is filled with delicate cytoplasmic processes of the bone cell. The canaliculi helps bone cell to receive food and oxygen and eliminate wastes.

Functions of Bone

• Gives shape to the body.
• Provides skeletal support to the body.
• Protects important body organs, like brain, lungs, etc.
• Acts as a storage site of calcium and phosphate.
• Anchor the muscles.

Fluid Connective Tissue

This tissue links the various parts of the body and ­maintains continuity in the body. Blood and lymph are two kinds of fluid connective tissue.

Blood: Blood is a fluid connective tissue and is the main circulating medium that helps in the transport of various substances. In this tissue, the cells or corpuscles move in a fluid or liquid matrix or a medium known as blood plasma. This plasma forms 55 per cent of the total volume of blood (Fig. 2.29). It is a complex fluid and it consists of inorganic salts and organic compounds.

Other organic compounds present include glucose, amino acids, lipids, vitamins, enzymes, hormones and waste substances, such as urea, uric acid, etc.

The blood plasma does not consist of protein fibres but possess cells known as blood corpuscles or blood cells. These blood corpuscles include (a) Red blood corpuscles (RBCs) or erythrocytes (b) White blood cells (WBCs) or leucocytes (c) Platelets.

• • Red blood corpuscles (RBCs): They are present in large number and possess iron-containing red respiratory pigment, the haemoglobin. In mammals, erythrocytes are circular, biconcave, disc-like and devoid of nuclei. Hence, mammalian erythrocytes have an increased surface area for gaseous exchange and they bear much more haemoglobin in them as compared to RBCs of other animals. RBCs play a very crucial role in the transport of oxygen.
  • White blood cells (WBCs): The WBCs are present in much smaller number and nucleated. They play an important role in the body’s defense mechanism.
• Phagocytes: These are capable of phagocytosis and helps in the defence of body by engulfing bacteria and other foreign substances. Phagocytes are of two types, namely granulocytes and agranular leukocytes.
  • Granulocytes have irregular-shaped nuclei and cytoplasmic granules with specific staining properties. They include neutrophils, basophils and eosinophils.
  • Agranular leukocytes have no cytoplasmic granules and include the monocytes. Monocytes consist of a large nucleus on one side and large amount of cytoplasm. They ultimately migrate to body tissues and transform into macrophages and histiocytes.
• Immunocytes: These produce antibodies and are involved in immune response. They include lymphocytes that have approximately spherical nucleus and meagre cytoplasm devoid of granules. Few of the lymphocytes later on transform into plasma cells.

Blood platelets: They are very small, anucleated, fragile fragments of giant bone marrow cells termed as megakaryocytes. Blood is found in blood vessels known as arteries, veins and capillaries that are connected together to form the circulatory system. The elaborate branching network of vessels enables blood to reach every part of the body.

Lymph: Lymph is a colourless fluid that is filtered out of the blood capillaries. In lymph, WBCs are found abundantly. Lymph is devoid of RBCs and some blood proteins.

Functions of Lymph

• Lymph transports nutrients filtered by the blood capillaries and it comes back into the heart to be recirculated in the body.
• Lymph brings carbon dioxide and nitrogenous wastes from tissue fluid to blood.
• Lymph protects the body against infection as it contains WBCs in abundance. It makes up the immune system of the body.

Functions of Fluid Connective Tissue

• Blood transports nutrients, hormones and vitamins to the tissues.
• Blood transports excretory substances from the tissues to the liver and kidney.
• RBCs carry oxygen to the tissues.
• WBCs helps in producing antibodies to destroy pathogens and it also produces antitoxins that neutralize the toxins released by pathogens.
• Blood platelets disintegrate at the site of injury and helps in the clotting of blood, which prevents unnecessary loss of blood from the body.

Chapter 2 Tissues Nervous Tissue

Nervous tissue is a specialized tissue to transmit messages within the body. Brain, spinal cord and nerves are all made up of nervous tissue. Nervous tissue consists of highly specialized unit cells known as nerve cells or neurons.

Neurons are capable of receiving stimuli from within or outside the body and of conducting impulses or signals to various parts of the body. The impulse travels from one neuron to another neuron.

A neuron consists of the following three parts.

• Cyton or cell body: It consists of a central nucleus and cytoplasm with deeply stained particles called Nissl’s granules (i.e., clumps of ribosomes).
• Dendrons: These are short processes originating from the cyton and further branching into dendrites.
• Axon: It is a single, long, cylindrical process of uniform diameter. It forms fine branches at its end. Each such twig-like branch of axon ends in a swollen structure termed as synaptic knob or bouton. Bouton consists of acetylcholine-filled vesicles. Acetylcholine (Ach) is a vital neurotransmitter (i.e., a substance playing a crucial role in the transmission of nerve impulses inside the nervous system). Axon is also known as nerve fibre.

Functions: The dendrites receive impulses and the axon takes away impulses from the cell body.

Chapter 2 Tissues Fill In The Blanks

Question 1. ______ group of young meristematic cells of a growing organ, such as the tips of stem and root.
Answer. primordial meristem

Question 2. Parenchyma serves as ______ storage tissues.
Answer. Food

Question 3. Collenchyma is ______ in monocot stems, roots and leaves.
Answer. Absent

Question 4. Collenchyma is a ______.
Answer. Mechanical Tissue

Question 5. ______ provides mechanical support and elasticity.
Answer. Collenchyma

Question 6. ______ gives strength, rigidity, flexibility and elasticity to the plant body.
Answer. Sclerenchyma

Question 7. ______ enables plant body to withstand various strains.
Answer. Sclerenchyma

Question 8. Xylem and ______ is a vascular and mechanical tissues.
Answer. Phloem

Question 9. ______ of xylem are elongated cells with tapering ends.
Answer. Tracheids

Question 10. ______ forms the delicate lining of cavities (mouth, oesophagus, nose, pericardium, alveoli, etc.) and of blood vessels and covering of the tongue and skin.
Answer. Squamous epithelium

Question 11. ______ are found in the muscles of limbs, body wall, face, neck, etc.
Answer. Striated epithelium

Question 12. Smooth muscles are located in the walls of the hollow visceral organs except that of the heart, and hence, they are called ______.
Answer. visceral muscles

Question 13. Cardiac muscles show stripes of light and dark bands. Also, these muscle fibres show densely stained cross bands known as ______.
Answer. intercalated impulse

Question 14. ______ protects the body against infection, as it contains WBCs in abundance. It makes up the immune system of the body.
Answer. Lymph

Question 15. A group of cells that are similar in structure and which perform a specific function are called ______.
Answer. Tissues

Question 16. Founder of Histology ______.
Answer. Marcello Malphigi

Question 17. Arrange the order: Cells ______ Organ ______ Organism.
Answer. 1. Tissue    2. Organ System

Question 18. Cell growth is distributed uniformly in ______.
Answer. Animal tissues

Question 19. Full form of ATP ______.
Answer. Adenosine triphosphate

Question 20. ______ divides in two planes resulting to an increase in an organ, for example, leaf formation.
Answer. Plate meristem

Question 21. Cell divisions occur in all planes resulting in the increase of volume is ______.
Answer. Mass meristem

Question 22. ______ outermost layer of the young growing region that develops to give rise to epidermal tissue system.
Answer. Protoderm meristem

Question 23. ______ is found between the regions of permanent tissues.
Answer. Intercalary meristem

Question 24. ______ was first proposed by Hanstein (1868).
Answer. Histogen Cell Theory

Chapter 2 Tissues True or False

Question 1. Epithelial tissue is a protective tissue in animal body.
Answer. True

Question 2. The lining of blood vessels, lung alveoli and kidney tubules are all made up of epithelial tissue.
Answer. True

Question 3. Epithelial cells have a lot of intercellular spaces.
Answer. False

Question 4. Epithelial layer is a permeable layer.
Answer. True

Question 5. Epithelial layer does not allow the regulation of materials between body and external environment.
Answer. False

Chapter 2 Tissues Match The Columns

Question 1.

Select the correct option.

1. A-4, B-3, C-1, D-5, E-2
2. A-2, B-4, C-5, D-1, E-3
3. A-5, B-3, C-2, D-4, E-1
4. A-4, B-2, C-5, D-3, E-1

Answer. 1. A-4, B-3, C-1, D-5, E-2

Question 2.

Select the correct option.

1. A-4, B-3, C-1, D-5, E-2
2. A-3, B-5, C-4, D-1, E-2
3. A-5, B-1, C-3, D-2, E-4
4. A-2, B-3, C-4, D-1, E-5

Answer. 2. A-3, B-5, C-4, D-1, E-2

Question 3.

Select the correct option.

1. A-1, B-2, C-3, D-4
2. A-2, B-3, C-4, D-1
3. A-4, B-3, C-2, D-1
4. A-1, B-3, C-4, D-2

Answer. 3. A-4, B-3, C-2, D-1

Question 4.

Select the correct option.

1. A-3, B-4, C-1, D-2, E-5
2. A-5, B-1, C-4, D-3, E-2
3. A-3, B-2, C-4, D-1, E-5
4. A-4, B-5, C-3, D-2, E-1

Answer. 2. A-5, B-1, C-4, D-3, E-2

Question 5.

Select the correct option.

1. A-2, B-1, C-5, D-3, E-4
2. A-1, B-2, C-3, D-4, E-5
3. A-5, B-4, C-3, D-2, E-1
4. A-3, B-4, C-1, D-5, E-2

Answer. 4. A-3, B-4, C-1, D-5, E-2

Chapter 2 Tissues Long Answer Type Question And Answers

Question 1. Why are xylem and phloem called complex tissues? How are they different from each other?
Answer.

Xylem and phloem called complex tissues:

Both xylem and phloem consist of more than one type of cells, which coordinate to perform a common function.

Question 2. Discuss the location and function of muscular tissue.
Answer.

The location and function of muscular tissue:

Muscle tissues help in body movements (local and gross). For example, blood is transported mainly due to the visceral muscles in the walls of the vessels.

Question 3. Discuss the location and function of loose and dense connective tissue.
Answer.

Read and Learn More NEET Foundation Long Answer Questions

The location and function of loose and dense connective tissue:

Question 4. How are axon and dendrite are different from each other?
Answer.

Axon and Dendrite are different from each other As Follows:

Differences between axon and dendrite.

Tissues Long Answer Type Question And Answers

Class 11 Physics	Class 12 Maths	Class 11 Chemistry
NEET Foundation	Class 12 Physics	NEET Physics

Question 5. Discuss the differences between tracheids and vessels.
Answer.

The differences between tracheids and vessels:

Differences between tracheids and vessels.

Question 6. Describe the characteristic between red and white blood cells.
Answer.

Differences between red blood corpuscles and white blood cells:

Question 7. Discuss the differences between squamous and columnar epithelium.
Answer:

The differences between squamous and columnar epithelium:

Tissues 

Question 8. Describe the characteristic features between smooth, skeletal and cardiac muscles.
Answer:

The characteristic features between smooth, skeletal, and cardiac muscles:

Question 9. What are ligaments?
Answer:

Ligaments: These are elastic structures that connect bones to bones. The ligament strengthens the joint and allows normal movement but prevents over-flexing.

 

Question 10. What are megakaryocytes?
Answer:

Megakaryocytes Meaning:

Blood platelets are very small, enucleated, fragile fragments of giant bone marrow cells termed as megakaryocytes.

Question 11. What are neurons?
Answer:

Neurons:

Neurons can receive stimuli from within or outside the body and conduct impulses or signals to various parts of the body. The impulse travels from one neuron to another neuron.

Question 12. Pavement epithelium is another name of

1. Glandular epithelium
2. Squamous epithelium
3. Columnar epithelium
4. Cuboidal epithelium

Answer. 2. Squamous epithelium

Question 13. Which one of the following forms germinal epithelium of gonads?

1. Glandular epithelium
2. Squamous epithelium
3. Columnar epithelium
4. Cuboidal epithelium

Answer. 4. Cuboidal epithelium

Tissues

Question 14. Which one of the following lines the trachea or wind pipe?

1. Glandular epithelium
2. Ciliated epithelium
3. Columnar epithelium
4. Cuboidal epithelium

Answer. 4. Cuboidal epithelium

Question 15. Each muscle cell is enclosed in a thin and distinct plasma membrane known as

1. sarcolemma
2. sarcoplasm
3. sarcoreticulum
4. cell wall

Answer. 1. sarcolemma

Question 16. Which of the following helps in the movement of food in the alimentary canal?

1. Striated muscles
2. Cardiac muscles
3. Smooth muscles
4. Striped muscles

Answer. 3. Smooth muscles

Question 17. Which of the following muscles undergo rapid contraction and can get tired and may need rest?

1. Striated muscles
2. Cardiac muscles
3. Smooth muscles
4. Straight muscles

Answer. 1. Striated muscles

Question 18. Which muscles are found in the walls of the heart?

1. Striated muscles
2. Cardiac muscles
3. Smooth muscles
4. Straight muscles

Answer. 2. Cardiac muscles

Question 19. ______ is the simplest and most widely distributed connective tissue.

1. Dense regular connective tissue
2. Adipose tissue
3. Fluid connective tissue
4. Areolar tissue

Answer. 4. Areolar tissue

Question 20. Tendons and ligaments are included in

1. dense regular connective tissue
2. adipose tissue
3. fluid connective tissue
4. areolar tissue

Answer. 1. dense regular connective tissue

Question 21. Which of the following keeps visceral organs in position, and forms shock-absorbing cushions around kidneys and eye balls?

1. Dense regular connective tissue
2. Adipose tissue
3. Fluid connective tissue
4. Areolar tissue

Answer. 2. Adipose tissue

NEET Biology Tissues MCQs

Chapter 2 Tissues Multiple-Choice Questions And Answers

Direction: Choose the correct option for each question. There is only one correct response for each question.

Question 1. A tissue is made up of

1. a group of cells that perform similar or common functions.
2. cells with similar structures but very different functions.
3. same type of cells which form organs.
4. cells with dissimilar structures and functions.

Answer. 1. a group of cells that perform similar or common functions.

Question 2. Which of the following involves the study of tissue?

1. Cytology
2. Embryology
3. Histology
4. Pathology

Answer. 3. Histology

Question 3. Which of the following is not a simple tissue

1. Parenchyma
2. Xylem
3. Collenchyma
4. Sclerenchyma

Answer. 2. Xylem

Read and Learn More NEET Foundation Multiple Choice Questions

Question 4. Parenchyma is a type of

1. simple tissue
2. complex tissue
3. xylem
4. phloem

Answer. 1. simple tissue

Question 5. The husk of coconut is made up of

1. apical meristem
2. intercalary meristem
3. collenchyma
4. sclerenchyma

Answer. 4. sclerenchyma

NEET Biology Tissues MCQs 

Question 6. Which tissue is responsible for the length of the plant?

1. Apical meristem
2. Lateral meristem
3. Intercalary Meristem
4. Epidermis

Answer. 1. Apical meristem

Question 7. Meristems help in

1. absorption of water
2. absorption of minerals
3. translocation of food
4. growth of the plants

Answer. 4. growth of the plants

Question 8. The apical meristem of the root is present

1. only in radicles.
2. in all the roots.
3. only in tap roots.
4. only in adventitious roots.

Answer. 2. in all the roots.

Question 9. Sieve tubes are present in

1. phloem
2. xylem
3. collenchyma
4. sclerenchyma

Answer. 1. phloem

Question 10. Collenchyma in plants provide

1. flexibility
2. buoyancy
3. rigidity
4. both (a) and (c)

Answer. 1. flexibility

NEET Biology Tissues MCQs 

Question 11. Girth of stem increases due to

1. apical meristem
2. lateral meristem
3. intercalary meristem
4. vertical meristem

Answer. 2. lateral meristem

Question 12. The term tissue was given by

1. Robert Hooke
2. Mayer
3. Bichat
4. Leeuwenhoek

Answer. 3. Bichat

Question 13. Which of the following components of xylem is living?

1. Tracheids
2. Vessels
3. Xylem parenchyma
4. Xylem fibres

Answer. 3. Xylem parenchyma

Question 14. Tissue that is absent in monocots is

1. chlorenchyma
2. sclerenchyma
3. aerenchyma
4. collenchyma

Answer. 4. Collenchyma

Question 15. Phloem in the plant performs the function of

1. conduction of food
2. conduction of water
3. providing support
4. photosynthesis

Answer. 1. conduction of food

NEET Biology Tissues MCQs 

Question 16. Parenchyma: Simple:: Phloem: ?

1. Simple
2. Collenchyma
3. Complex
4. Xylem

Answer. 3. Complex

Question 17. The tissue which is composed of flat cells that line body cavities is

1. columnar
2. cuboidal
3. ciliated columnar
4. squamous

Answer. 4. squamous

Question 18. Maximum intercellular substance is found in

1. connective tissue
2. nervous tissue
3. epithelial tissue
4. muscular tissue

Answer. 1. connective tissue

Question 19. The tissue connecting bone to bone is called

1. tendon
2. ligament
3. areolar tissue
4. adipose tissue

Answer. 2. ligament

Question 20. Fat is abundant in

1. liver cells
2. areolar tissue
3. adipose tissue
4. lymph glands.

Answer. 3. adipose tissue

NEET Biology Tissues MCQs 

Question 21. The mineral found in red pigment of human blood is

1. Mg
2. Fe
3. Ca
4. Cr

Answer. 2. Fe

Question 22. Which of the following tissues is mainly composed of dead cells?

1. Phloem
2. Epidermis
3. Xylem
4. Endodermis

Answer. 3. Xylem

Question 23. Largest blood cells are

1. monocytes
2. neutrophils
3. lymphocytes
4. basophils

Answer. 1. monocytes

Question 24. Fluid part of blood after removing corpuscles is

1. Plasma
2. Lymph
3. Serum
4. Vaccine

Answer. 1. Plasma

Question 25. Tendon is a structure which connects

1. a bone with another bone
2. a muscle with another muscle
3. a nerve with a muscle
4. a bone with a muscle

Answer. 4. a bone with a muscle

Animal Tissues MCQs for NEET 

Question 26. Which part of the bone is specialized to form blood cells?

1. Haversian canal
2. Red bone marrow
3. Osteoblasts
4. Osteocytes

Answer. 2. Red bone marrow

Question 27. Major inorganic component of bone is

1. calcium phosphate
2. calcium carbonate
3. sodium hydroxide
4. potassium hydroxide

Answer. calcium phosphate

Question 28. The unit of nervous system is

1. cyton
2. axon
3. neuron
4. dendrite

Answer. neuron

Question 29. Cartilage is not found in

1. nose
2. ear
3. kidney
4. larynx

Answer. 3. kidney

Question 30. The efferent part of neuron is

1. axon
2. dendrites
3. cyton
4. both (a) and (b)

Answer. 1. axon

Animal Tissues MCQs for NEET 

Question 31. The following are characteristic features of plant tissues.

(1) Dead supportive tissues are more abundant.

(2) There is differentiation of meristematic and permanent tissue.

(3) Differentiation of meristematic and permanent tissues is absent.

(4) Organization of tissues is complex.

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 1. Only (1) and (2)

Question 32. Meristematic tissues are

(1) similar in structure.

(2) not similar in structure.

(3) have thin cell wall.

(4) have thick cell wall.

Select the correct option.

1. Only (1) and (2)
2. Only (1) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 2. Only (1) and (3)

Question 33. Parenchyma can be classified as

(1) thin walled living cells.

(2) thick walled living cells.

(3) distributed in almost all parts of the plant body.

(4) distributed mostly in the aerial parts of the plant body.

Select the correct option.

1. Only (1) and (2)
2. Only (1) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 2. Only (1) and (3)

Question 34. Which of the following are parts of the phloem?

(1) Sieve tubes

(2) Companion cells

(3) Tracheids

(4) Vessels

Select the correct option.

1. Only (1) and (2)
2. Only (1) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 1. Only (1) and (2)

Animal Tissues MCQs for NEET 

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NEET Foundation	Class 12 Physics	NEET Physics

Question 35. Complex permanent tissues of the plant are made up of

(1) more than one type of cells.

(2) only one type of cells.

(3) only xylem.

(4) xylem and phloem.

Select the correct option.

1. Only (1) and (2)
2. Only (1) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 4. Only (1) and (4)

Question 36. Xylem tissues transport

(1) water from root to plant.

(2) minerals from root to plant.

(3) food all through the plant.

(4) food to the leaves.

Select the correct option.

1. Only (1) and (2)
2. Only (1) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 1. Only (1) and (2)

Question 37. The characteristic features of squamous epithelium are

(1) component cells are pillar like.

(2) component cells are thin and flat.

(3) the nucleus lies in the centre of the cell.

(4) the nucleus is located near the base of the cell.

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 2. Only (2) and (3)

Question 38. Tendons can be defined as

(1) inelastic

(2) elastic

(3) connects bone to bone

(4) joins muscles to bone

Select the correct option.

1. Only (1) and (2)
2. Only (1) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 4. Only (1) and (4)

Question 39. Cartilage is

(1) hard and inflexible

(2) porous

(3) flexible

(4) non-porous

Select the correct option.

1. Only (1) and (2)
2. Only (1) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 3. Only (3) and (4)

Question 40. Red blood corpuscles

(1) are colourless.

(2) are red in colour.

(3) nucleus is present.

(4) nucleus is absent.

Select the correct option.

1. Only (1) and (2)
2. Only (1) and (3)
3. Only (3) and (4)
4. Only (2) and (4)

Answer. 4. Only (2) and (4)

Animal Tissues MCQs for NEET 

Question 41. What will happen if a bone is dipped in HCl?

(1) Its mineral matters dissolve.

(2) Only organic matter is left.

(3) Mineral matter does not dissolve.

(4) Organic matter dissolves.

Select the correct option.

1. Only (1) and (2)
2. Only (1) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 1. Only (1) and (2)

Question 42. Blood corpuscles are made of

(1) red blood cells

(2) white blood cells

(3) lymph

(4) granulocytes

Select the correct option.

1. Only (1) and (2)
2. Only (1) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 1. Only (1) and (2)

Question 43. The following are functions of cartilage.

(1) It provides support and flexibility to the body parts.

(2) It smoothens surface at joins.

(3) It provides rigidity to the body parts.

(4) It makes surfaces rough.

Select the correct option.

1. Only (1) and (2)
2. Only (1) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 1. Only (1) and (2)

Question 44. Fluid connective tissues

(1) does not include blood and lymph.

(2) it includes blood and lymph.

(3) links the different parts of the body.

(4) doesn’t link the different parts of the body.

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 2. Only (2) and (3)

Question 45. Which muscles act involuntarily?

(1) Striated muscles

(2) Smooth muscles

(3) Cardiac muscles

(4) Skeletal muscles

Select the correct option.

1. Only (1) and (2)
2. Only (2) and (3)
3. Only (3) and (4)
4. Only (1) and (4)

Answer. 2. Only (2) and (3)

Plant Tissues NEET MCQs 

Question 46. Plant length is increased by

1. Apical meristems
2. Lateral meristems
3. Periblem
4. Parenchyma

Answer. 1. Apical meristems

Question 47. The cell division is restricted to

1. Meristematic cells
2. Permanent cells
3. Secretory cells
4. All the above

Answer. 1. Meristematic cells

Question 48. Active divisions take place in the cells of

1. Xylem
2. Phloem
3. Sclerenchyma
4. Cambium

Answer. 4. Cambium

Question 49. Simple tissues are these

1. Parenchyma, Xylem and collenchyma
2. Parenchyma, collenchyma and Sclerenchyma
3. Parenchyma, Xylem and Sclerechyma
4. Parenchyma, Xylem and Phloem

Answer. 2. Parenchyma, collenchyma and Sclerenchyma

Question 50. Complex tissue consists of

1. Different type of cells carrying out the same function
2. Different types of cells carrying out different functions
3. Same type of cells having the same origin and carry the same function
4. Different types of cells having the same origin and carry the same function

Answer. 2. Different types of cells carrying out different functions

Plant Tissues NEET MCQs 

Question 51. The most common type of ground tissue is

1. Epidermis
2. Collenchyma
3. Sclerenchyma
4. Parenchyma

Answer. 4. Parenchyma

Question 52. Collenchyma differs from sclerenchyma in

1. Retaining cytoplasm at maturity
2. Having thick walls
3. Having a wide lumen
4. Being meristematic

Answer. 1. Having thick walls

Question 53. Whose living cells provide tensile and mechanical strength

1. Collenchyma
2. Sclerenchyma
3. Phloem
4. Sclereids

Answer. 1. Collenchyma

Question 54. Lignified elongated dead cells are

1. Parenchyma
2. Collenchyma
3. Sclerenchyma
4. None of the above

Answer. 3. Sclerenchyma

Question 55. Phloem in the plants perform the function of

1. Conduction of food
2. Conduction of water
3. Providing support
4. Photosynthesis

Answer. 1. Conduction of food

Plant Tissues NEET MCQs 

Question 56. Pavement epithelium is the name of

1. Squamous epithelium
2. Cuboidal epithelium
3. Ciliated epithelium
4. Columnar epithelium

Answer. 1. Squamous epithelium

Question 57. Brush bordered epithelium is found in

1. Stomach
2. Small intestine
3. Fallopian tube
4. Trachea

Answer. 2. Small intestine

Question 58. Ciliated epithelium is found in

1. Tongue
2. Oesophagus
3. Trachea
4. Uterus

Answer. 3. Trachea

Question 59. Which type of tissue forms glands?

1. Epithelial
2. Connective
3. Nervous
4. Muscle

Answer. 1. Epithelial

Question 60. What are the functions of goblet cells?

1. Production of HCI
2. Production of mucus
3. Production of enzymes
4. Production of hormones

Answer. 2. Production of mucus

Plant Tissues NEET MCQs 

Question 61. The end of a long bone is connected to another bone by

1. Ligament
2. Tendon
3. Cartilage
4. Muscle

Answer. 1. Ligament

Question 62. When boiled in water collagen changes into

1. Gelatin
2. Reticulin
3. Elastin
4. Myosin

Answer. 1. Gelatin

Question 63. Fluid part of blood after removal of ­corpuscles is

1. Plasma
2. Lymph
3. Serum
4. Vaccine

Answer. 1. Plasma

Question 64. Which are not true cells in the blood?

1. Platelets
2. Monocytes
3. Basophils
4. Neutrophils

Answer. 1. Platelets

Question 65. Sprain is caused by excessive pulling of

1. Nerves
2. Tendons
3. Muscles
4. Ligaments

Answer. 4. Ligaments

Chapter 2 Tissues NEET Questions 

Question 66. Tendon is a structure which connects

1. A bone with another bone
2. A muscle with a bone
3. A nerve with a muscle
4. A muscle with a muscle

Answer. 2. A muscle with a bone

Question 67. Which of the following plant tissues do not possess living protoplasm at maturity?

1. Sclerenchyma
2. Collenchyma
3. Tracheids
4. Epidermis

Answer. 1. Sclerenchyma

Question 68. White fibres of connective tissue are made up of

1. Elastin
2. Reticular fibre
3. Collagen
4. Myosin

Answer. 3. Collagen

Question 69. The study of tissues and their functions is known as

1. histology
2. physiology
3. anatomy
4. morphology

Answer. 1. histology

Question 70. Which one is a meristematic tissue?

1. xylem
2. parenchyma
3. apical tissues
4. phloem

Answer. 3. apical tissues

Chapter 2 Tissues NEET Questions 

Question 71. Tracheids are components of

1. xylem
2. phloem
3. intercalary tissues
4. collenchyma

Answer. 1. xylem

Question 72. Areolar tissue is a

1. ligament
2. connective tissue
3. muscle
4. nervous tissue

Answer. 2. connective tissue

Question 73. Which tissue provides mechanical strength to plants?

1. parenchyma
2. chlorenchyma
3. collenchyma
4. sclerenchyma

Answer. 4. sclerenchyma

Question 74. Ciliated epithelium is found in

1. stomach
2. intestine
3. oesophagus
4. trachea

Answer. 4. trachea

Question 75. Cardiac muscle fibres are

1. striated and voluntary
2. striated and involuntary
3. non-striated and voluntary
4. non-striated and involuntary

Answer. 2. striated and involuntary

Chapter 2 Tissues NEET Questions 

Question 76. Name the cambium present between phloem and xylem.

1. Shoot cambium
2. Root cambium
3. Vascular cambium
4. Cork cambium

Answer. 3. Vascular cambium

Question 77. Cambium found on lateral parts of plants on outer side is known as

1. Vascular cambium
2. Cork cambium
3. Shoot cambium
4. Root cambium

Answer. 2. Cork cambium

Question 78. In which of the following, pith and cortex never differentiates?

1. Monocot stem
2. Dicot stem
3. Monocot root
4. Dicot root

Answer. 1. Monocot stem

Question 79. For which of the following vital function, the death of protoplasm is a prerequisite?

1. Transport of sap
2. Transport of food
3. Absorption of water
4. Gaseous exchange

Answer. 1. Transport of sap

Question 80. Which of the following forms cork?

1. Cork cambium (phellogen)
2. Vascular cambium
3. Phloem
4. Xylem

Answer. 1. Cork cambium (phellogen)

Chapter 2 Tissues NEET Questions 

Question 81. Pericycle of roots produces

1. Lateral roots
2. Vascular bundles
3. Adventitious buds
4. Hydathodes

Answer. 1. Lateral roots

Question 82. Organization of shoot apex into corpus and tunica is governed chiefly by

1. Planes of cell division
2. Regions of meristematic activity
3. Rate of cell growth
4. Rate of shoot tip growth

Answer. 1. Planes of cell division

Question 83. Which of the following tissues has dead cells?

1. Parenchyma
2. Sclerenchyma
3. Collenchyma
4. Epithelial tissue

Answer. 2. Sclerenchyma

Question 84. Girth of stem increases due to

1. Apical meristem
2. lateral meristem
3. intercalary meristem
4. vertical meristem

Answer. 2. lateral meristem

Question 85. Meristematic tissues in plant are

1. localized and permanent
2. not limited to certain regions
3. localized and dividing cells
4. growing in volume.

Answer. 3. localized and dividing cells

Question 86. Flexibility in plants is due to

1. collenchyma
2. sclerenchyma
3. parenchyma
4. chlorenchyma

Answer. 1. collenchyma

Question 87. Parenchyma cells are

1. relatively unspecified and thin walled
2. thick waled and specialized
3. lignified
4. none of these

Answer. 1. relatively unspecified and thin walled

NEET Foundation Biology Chapter 2 

Chapter 2 Tissues Practice Exercises

Question 1. Which of the following tissues has dead cells?

1. Parenchyma
2. Sclerenchyma
3. Collenchyma
4. Epithelial tissue

Answer. 2. Sclerenchyma

Question 2. Find out the incorrect sentence from the following.

1. Parenchymatous tissues have intercellular spaces.
2. Collenchymatous tissues are irregularly thickened at corners.
3. Apical and intercalary meristems are permanent tissues.
4. Meristematic tissues, in its early stage, lack vacuoles.

Answer. 3. Apical and intercalary meristems are permanent tissues.

Question 3. Girth of stem increases due to

1. apical meristem
2. lateral meristem
3. intercalary meristem
4. vertical meristem

Answer. 2. lateral meristem

Question 4. Which cell does not have perforated cell wall?

1. Tracheids
2. Companion cells
3. Sieve tubes
4. Vessels

Answer. 2. Companion cells

Question 5. Intestine absorbs the digested food materials. What type of epithelial cells are responsible for that?

1. Stratified squamous epithelium
2. Columnar epithelium
3. Spindle fibres
4. Cuboidal epithelium

Answer. 2. Columnar epithelium

Question 6. A person met with an accident in which two long bones of hand were dislocated. Which among the following may be the possible reason?

1. Tendon break
2. Break of skeletal muscle
3. Ligament break
4. Areolar tissue break

Answer. 3. Ligament break

NEET Foundation Biology Chapter 2 

Question 7. While doing work and running, you move your organs, like hands, legs, etc. Which among the following is correct?

1. Smooth muscles contract and pull the ligament to move the bones.
2. Smooth muscles contract and pull the tendons to move the bones.
3. Skeletal muscles contract and pull the ligament to move the bones.
4. Skeletal muscles contract and pull the tendon to move the bones.

Answer. 4. Skeletal muscles contract and pull the tendon to move the bones.

Question 8. Which muscles act involuntarily?

(1) Striated muscles

(2) Smooth muscles

(3) Cardiac muscles

(4) Skeletal muslces

1. (1) and (2)
2. (2) and (3)
3. (3) and (4)
4. (1) and (4)

Answer. 2. (2) and (3)

Question 9. Meristematic tissues in plants are

1. localized and permanent.
2. not limited to certain regions.
3. localized and dividing cells.
4. growing in volume.

Answer. 3. localized and dividing cells.

Question 10. Which is not a function of epidermis?

1. Protection from adverse condition
2. Gaseous exchange
3. Conduction of water
4. Transpiration

Answer. 3. Conduction of water

Question 11. Which of the following sentence is incorrect?

1. Blood has matrix containing proteins, salts and hormones.
2. Two bones are connected with ligament.
3. Tendons are non-fibrous tissue and fragile.
4. Cartilage is a form of connective tissue.

Answer. 3. Tendons are non-fibrous tissue and fragile.

Question 12. Cartilage is not found in

1. Nose
2. Ear
3. Kidney
4. Larynx

Answer. 3. Kidney

NEET Foundation Biology Chapter 2 

Question 13. Fats are stored in human body as

1. Cuboidal epithelium
2. Adipose tissue
3. Bones
4. Cartilage

Answer. 2. Adipose tissue

Question 14. Bone matrix is rich in

1. Fluoride and calcium.
2. Calcium and phosphorus.
3.  Calcium and potassium.
4. Phosphorus and potassium.

Answer. 2. Calcium and phosphorus.

Question 15. Contractile proteins are found in

1. Bones
2. Blood
3. Muscles
4. Cartilage

Answer. 3. Muscles

Question 16. Voluntary muscles are found in

1. alimentary canal
2. limbs
3. iris of the eye
4. bronchi of lungs

Answer. 2. limbs

Question 17. Nervous tissue is not found in

1. brain
2. spinal cord
3. tendons
4. nerves

Answer. 3. tendons

Question 18. Nerve cell does not contain

1. axon
2. nerve endings
3. tendons
4. dendrites

Answer. 3. tendons

Question 19. Which of the following helps in the repair of tissue and fills up the space inside the organ?

1. Tendon
2. Adipose tissue
3. Areolar
4. Cartilage

Answer. 3. Areolar

Question 20. The muscular tissue which function through out the life continuously without fatigue is

1. skeletal muscle
2. cardiac muscle
3. smooth muscle
4. voluntary muscle

Answer. 2. cardiac muscle

NEET Foundation Biology Chapter 2 

Question 21. Which of the following cells is found in the cartilaginous tissue of the body?

1. Mast cells
2. Basophils
3. Osteocytes
4. Chondrocytes

Answer. 4. Chondrocytes

Question 22. The dead element present in the phloem is

1. companion cells
2. phloem fibres
3. phloem parenchyma
4. sieve tubes

Answer. 2. phloem fibres

Question 23. Which of the following does not lose their nucleus at maturity?

1. Companion cells
2. Red blood cells
3. Vessel
4. Sieve tube cells

Answer. 1. Companion cells

Question 24. In desert plants, the rate of water loss gets reduced due to the presence of

1. cuticle
2. stomata
3. lignin
4. suberin

Answer. 1. cuticle

Question 25. A long tree has several branches. The tissue that helps in the side ways conduction of water in the branches is

1. collenchyma
2. xylem parenchyma
3. parenchyma
4. xylem vessels

Answer. 4. xylem vessels

Question 26. If the tip of sugarcane plant is removed from the field, even then it keeps on growing in length. It is due to the presence of

1. cambium
2. apical meristem
3. lateral meristem
4. intercalary meristem

Answer. 4. intercalary meristem

Question 27. A nail is inserted in the trunk of a tree at a height of 1 metre from the ground level. After 3 years, the nail will

1. move downwards.
2. move upwards.
3. remain at the same position.
4. move sideways.

Answer. 3. remain at the same position.

Question 28. Parenchyma cells are

1. relatively unspecified and thin walled.
2. thick walled and specialized.
3. lignified
4. none of these

Answer. 1. relatively unspecified and thin walled.

Question 29. Flexibility in plants is due to

1. collenchyma
2. sclerenchyma
3. parenchyma
4. chlorenchyma

Answer. 1. collenchyma

NEET Foundation Biology Chapter 2 

Question 30. Cork cells are made impervious to water and gases by the presence of

1. cellulose
2. lipids
3. suberin
4. lignin

Answer. 3. suberin

Question 31. Survival of plants in terrestrial environment has been made possible by the presence of

1. intercalary meristem
2. conducting tissue
3. apical meristem
4. parenchymatous tissue

Answer. 2. conducting tissue

NEET Biology Tissues MCQs 

Question 32. Select the incorrect statement from the following.

1. The nature of matrix differs according to the function of the tissue.
2. Fats are stored below the skin and in between the internal organs.
3. Epithelial tissues have intercellular spaces between them.
4. Cells of striated muscles are multinucleate and unbranched.

Answer. 3. Epithelial tissues have intercellular spaces between them.

Chapter 2 Tissues Short Answer Type Question And Answers

Question 1. If a potted plant is covered with a glass jar, water vapours appear on the wall of glass jar. Explain why?
Answer.

If a potted plant is covered with a glass jar, water vapours appear on the wall of the glass jar

It occurs due to transpiration.

Tissues Notes

Read And Learn More NEET Foundation Short Answer Questions

Question 2. Discuss the characteristics of meristematic tissue.
Answer.

The characteristics of meristematic tissue:

The cells are oval, rounded or polygonal in shape. The cells are living with thin cellulose walls and without any intercellular spaces The cells are rich in cytoplasm with very small vacuoles. The cells are diploid and undergoes mitosis. The cells do not contain reserve food materials, endoplasmic reticulum and plastids.

Question 3. Discuss the characteristics differences between sclerenchymatous fibres and sclereids.
Answer.

The characteristics differences between sclerenchymatous fibres and sclereids:

Question 4. What are sieve tubes?
Answer.

Sieve tubes:

These are slender, tube-like structures that consist of elongated thin-walled cells, placed end to end. The end walls of these cells are perforated by several pores and are known as sieve plates.

Question 5. Describe the differences between tendons and ligaments.
Answer.

The differences between tendons and ligaments:

Question 6. Discuss the differences between bone and cartilage.
Answer.

The differences between bone and cartilage:

Question 7. What are phagocytes?
Answer.

Phagocytes:

These are capable of phagocytosis and helps in the defence of body by engulfing bacteria and other foreign substances. Phagocytes are of two types, namely granulocytes and agranular leukocytes

Question 8. Discuss the differences between endocrine and exocrine glands.
Answer.

The differences between endocrine and exocrine glands:

Question 9. Describe characteristic features between unicellular and multicellular glands.
Answer.

Characteristic features between unicellular and multicellular glands:

Question 10. Discuss the differences between plant and animal tissues.
Answer:

The differences between plant and animal tissues:

Question 11. What do you understand by the term ‘Division of labour’ in the organisms?
Answer:

‘Division of labour’ in the organisms:

Division of labor in organisms enables a smooth and efficient functioning in the body for better survival. Different functions are performed by different groups of cells in an organism, and this is called division of labour in the organisms.

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Question 12. What is histology?
Answer:

Histology:

The study of tissues is known as histology.

Question 13. What do you understand by tissue?
Answer:

Tissue:

Tissue is a group of cells that are similar in structure and organized together to perform a specific function.

Question 14. Where is apical meristem found?
Answer:

Apical Meristem:

Apical meristem is present at the growing tips of stems and roots. Their main function is to initiate growth in new cells of seedlings, at the tip of roots and shoots.

Question 15. Discuss the characteristics of plant tissues.
Answer:

The characteristics of plant tissues:

• Plant tissues provide mechanical strength to the internal as well as external organs.
• Provide elasticity and flexibility to the plant organs.
• Plant tissues help in the transportation of materials across the plant body and prevents loss of water.
• They undergo division to help the plants to grow both in length and girth.
• The plant tissues are involved in many metabolic processes, such as photosynthesis, respiration, etc.

Question 16. What are meristematic tissues?
Answer:

Meristematic Tissues:

Meristematic tissue is a group of dividing cells that has the capacity to divide and re-divide and help in the growth of plants.

Question 17. What do you understand by the term histogen?
Answer:

Histogen:

Dermatogen produces epidermis, where periblem gives rise to cortex and endodermis and plerome to vascular bundle and pith. These three layers were termed as histogen.

Flowchart Of Tissue

Question 18. Discuss different types of meristematic tissues.
Answer:

Different types of meristematic tissues:

Question 19. Discuss the characteristics features between meristematic and permanent tissue.
Answer:

The characteristics features between meristematic and permanent tissue:

Question 20. How are simple tissues different from complex tissues in plants?
Answer:

Simple tissues are made up of one type of cells which coordinate to perform a common function. Complex tissues are made up of more than one type of cells. All these coordinate to perform a common function.

Question 21. How many types of elements together make up the xylem tissue? Name them.
Answer:

Xylem is a complex tissue. It is made up of the following four kinds of cells or elements.

• Tracheids
• Vessels
• Xylem parenchyma
• Xylem fibres

Question 22. Which tissue makes up the husk of coconut?
Answer:

The husk of a coconut is made up of sclerenchyma tissue.

Question 23. What are the constituents of phloem?
Answer:

Constituents Of Phloem:

Phloem is the food conducting tissue in plants. It is made up of four components as listed below.

• Sieve tubes
• Companion cells
• Phloem parenchyma
• Phloem fibres

Question 24. Discuss the differences between parenchyma, collenchyma and sclerenchyma.
Answer:

The differences between parenchyma, collenchyma and sclerenchyma:

Question 25. Discuss the characteristics features between xylem and phloem.
Answer:

The characteristics features between xylem and phloem:

Question 26. What do you understand by stomata?
Answer:

Stomata:

Stomata are the pores found in the epidermis of leaves, stems and other organs, which are used to monitor gaseous exchange.

Biology Chapter 1 The Fundamental Unit Of Life

The Fundamental Unit Of Life

If you ever come across a brick wall being constructed, then you can see that bricks are the basic building blocks of a wall. Similarly, cells are the fundamental units of your body. In simple definition, cells are sacs of fluid enveloped by membranes with chemicals and organelles embedded inside the fluid.

Though an organism possesses few other structures that are smaller than a cell and yet, however, cell is considered to be the smallest part of an organism. Robert Hooke (1665) discovered the cell, while studying a thin slice of cork through a crude microscope. He observed that cork resembled the structure of a honeycomb having many small compartments.

He called these little compartments as ‘cells’ (in Latin, ‘cellula’, which means ‘a little room’). His discovery was published in a book ‘Micrographia’. The ability to produce energy, synthesize hormones, transmit hereditary factors are examples of a few events that take place within the tiny building blocks of life called ‘Cells’.

Read and Learn More: NEET Foundation Notes

Chapter 1 The Fundamental Unit Of Life Architecture of Living Organisms

When you observe the inner layer of an onion by dropping iodine solution followed by a cover slip under high powers of a compound microscope. The structures of inner layer look similar to each other. Together they form a big structure like an onion bulb. Hence, we concluded that any organism despite different sizes have similar small structures visible under microscope.

The small structure that we observe are the basic structural and functional unit of onion bulbs. There are also single cells that live on their own, such as Amoeba, Chlamydomonas, Paramecium, and Bacteria. These organisms are called unicellular organisms. Many cells group together in a single body to form multicellular organisms like fungi.

Invention of the Microscope

Invention of the microscope was a milestone with regard to learning the delicate details of internal arrangement of the cell. Cells are microscopic structures not visible to human eyes. Anton van Leeuwenhoek is the father of microbiology who in the late 17th century became the first man to make and use a real microscope.

Ordinary compound microscope is an optical instrument that consists of two convex lenses of short focal lengths. This microscope can magnify the image of a tiny object up to 1000 times. Electron microscope uses electron beams to illuminate a specimen object and create a magnified image.

It magnifies to over 2,00,000 times the magnification of an ordinary compound microscope. The variations between the working of a light microscope and electron microscope is discussed.

Differences between light microscope and electron microscope

Cell Theory

Jacob Matthias Schleiden (1838), a German botanist and Theodor Schwann (1839), a German zoologist stated that cells are the fundamental and building blocks of all plants and animals. Their discoveries led to the formulation of the cell theory. They postulated that all animals and plants are made up of cell.

History of cell biology

Cell The Fundamental Unit Of Life

Rudolf Virchow (1855) further refined the cell theory and gave the idea that all cells arise from pre-existing cells.

The main postulates of the modern cell theory are as follows.

• All organisms are made up of one or more cells and cell products.
• All metabolic reactions occur in cells. Hence, cells are the structural and functional units of life.
• All cells arise from pre-existing cells, as an animal gives birth only to an animal and a plant gives rise only to a plant.
• An organism begins its life as a single cell.
• Virus is an exception of this theory.

Chapter 1 The Fundamental Unit Of Life Cell Shape

Living cell has the capacity to perform certain basic functions that are characteristics of all living forms. Depending upon the functions perfomed by cells are of different shapes and sizes. Most plant and animal cells are basically the same when formed.

By the processes of maturation and differentiation, they acquire different forms. Different parts in human body performs different functions. The human body has heart to pump blood and stomach to digest food.

Eukaryotes are organisms with a well-defined membrane bound nucleus and other organelles. Eukaryotic cell is spherical in shape, but ultimately the shape of a cell is governed by the specific function of the cell. The shape of the cell may be variable or fixed.

For example, amoeba changes its shape and white blood cells or leucocytes are spherical in circulating blood, but in other situations they become irregular in shape by producing pseudopodia. Cells have fixed shape in most of the plants and animals.

In unicellular organisms, the cell shape is determined by the hard plasma membrane (for example, Paramecium) and exoskeleton (for example, Elphidium). In multicellular organisms, the cell shape is mainly determined by its functional adaptations, and also by the surface tension, viscosity of the protoplasm, the mechanical pressure exerted by adjacent cells and the presence of a rigid cell wall such as in plant cells.

Cell Volume

Cell volume is almost consistent for a specific cell type and it is not dependent on the size of an organism. For example, in a bull, horse and mouse, the kidney and liver cells are almost of the same size. The variation in the total mass of the organ as well as organism is determined by the number and not the volume of the cells.

Cell Number

The number of cells in organisms is related to the size of the organism. Hence, the small-sized organisms have less number of cells as compared to the largesized organism. In most multicellular organisms, the number of cells is not fixed, except a few such as rotifers and nematodes. In human beings, the number of cells present in the body is approximately 100 trillion (10¹⁴).

Chapter 1 The Fundamental Unit Of Life Structural Organization of a Cell

Microscopic studies reveal that most cells have the same basic structural architecture. The cells have a jellylike substance called protoplasm bound by a cell membrane. The term protoplasm was coined by Purkinje in 1839. The protoplasm consists of the cytoplasm and a spherical body called nucleus. All the cells possess the following three major functional zones.

• The cell membrane or plasma membrane and the cell wall
• The nucleus
• The cytoplasm

Plasma Membrane

The plasma membrane is the outer boundary of the cell, enveloping the cytoplasm. In the cytoplasm, all the cell organelles and inclusions are embedded. All the cell organelles like mitochondria, chloroplasts, lysosomes, peroxisomes, Golgi apparatus, nucleus and endoplasmic reticulum are enclosed by the unit membrane. In animal cells, the plasma membrane is present in the outermost layer of the cell, whereas in plant cell it is present just beneath the cell wall.

Structure

Plasma membrane is a thin (about 7 nm), delicate, elastic, and selectively permeable membrane. The membrane is almost made up of 75% phospholipids. Also, it consists of proteins, cholesterol and polysaccharides.

Fluid Mosaic Model: S. J. Singer and G. L. Nicolson (1972) proposed a model called the fluid mosaic model to explain the structure of functional cell membranes or plasma membranes. According to this model, the plasma membrane is made up of a double layer of phospholipids.

The plasma membrane allows the movement of only certain substances across it and prevents the rest. Hence, it is selectively permeable. Two kinds of protein molecules float in the fluid phospholipid bilayerand they are explained as follows.

• Intrinsic or integral proteins completely cover the lipid bilayer.
• Extrinsic or peripheral proteins occur either on the outer surface or on the inner surface of the lipid membrane.

Functions

• Plasma membrane is a selectively permeable membrane, which regulates the entry and exit of the cell contents.
• It performs some physical activities, like diffusion and osmosis for the intake of some substances.
• In addition, some other biological activities like active transport and endocytosis are performed by the plasma membrane.
• The fluid nature of the plasma membrane makes it flexible and enables it to engulf substances or remove wastes by vesicle formation.
• Certain factors present in the plasma membranes play an important role in cell recognition in immune receptors.

Transport of Substances Across the Plasma Membrane

The passage of substances across the cell membrane takes place by three models listed as follows.

• Passive transport
• Active transport
• Bulk transport

Passive Transport

1. Diffusion: Certain substances can easily pass through the plasma membrane by a simple process of diffusion. Diffusion can take place in all states of matter and however, it takes place faster in the gaseous state.

Diffusion is the net movement of solute particles from a region of high concentration to the region of low concentration. When there is a difference of CO₂ concentration, inside and outside of a cell, gas moves out of the cell to the external environment, i.e., from the region of its higher concentration to the region of its lower concentration with the help of diffusion process.

Similarly, oxygen (O₂) enters the cell by the process of diffusion when the concentration of O₂ inside the cell becomes lower such as in Amoeba.

Diffusion is significant to biological systems due to the following reasons.

• Helps in the uniform distribution of substances in the cytoplasm.
• Assists in exchange of gases which is critical to processes, such as respiration and photosynthesis.
• Helps in attracting insects for pollination by spreading the scented chemicals from flowers.
• Helps in diffusion and the nutrient chemicals get absorbed into cells in the intestine of digestive system.

2. Osmosis: Osmosis is the passage of water or solvent from a region of high solvent concentration through a semi-permeable membrane to a region of low solvent concentration. Osmotic pressure is the external pressure needed to be applied so that there is no net movement of solvent across the membrane. Osmosis was first observed by Jean-Antoine Nollet (1748).

Osmosis is a mechanical diffusion process through which cells absorb water without spending any amount of energy. Osmosis is significant to biological systems due to the following reasons:

• Helps in the absorption of water by the roots from the soil.
• Helps in closing and opening of stomata on the leaves.
• Assists in cell-to-cell movement of water.

While studying the effects of different solutions on plant and animal cells, three conditions may arise depending upon the tonicity of the solution.

Hypotonic solution: When the medium surrounding the cell has a higher concentration of water (a very dilute solution) as compared to the inside of the cell, the cell will gain water by osmosis. This dilute solution is called hypotonic solution. In this situation, the cell swells up, as more water will enter the cell than leave the cell. These swollen RBC’s may finally burst, i.e., haemolysed.

1. Isotonic solution: When the medium surrounding the cell is of precisely the same water concentration as the cell, there will be no net movement of water across the membrane. This solution is called isotonic solution. For example, Ringer’s solution is an isotonic solution for the animal cells. In this condition, water moves across the plasma membrane in both directions and the amount of water going in is equal to the amount going out. Hence, the cell will retain the same size.

2. Hypertonic solution: When the medium has a lower concentration of water (a very concentrated solution) than the inside of the cell, the cell will lose water by osmosis. This concentrated solution is called hypertonic solution (Fig. 1.7). Here, water moves across the plasma membrane in both directions, but more water leaves the cell than enters the cell. Hence, the cell will shrink. In this condition, the plant cell gets plasmolysed and the animal cell gets crenated.

3. Facilitated transport/diffusion: The permease helps a molecule to diffuse through the membrane that it cannot penetrate alone. It promotes movement in a downhill direction only, i.e., in the direction of the concentration gradient and needs no metabolic energy to carry out the transport system. For example, in many animals, the facilitated diffusion helps in the transport of glucose (blood sugar) into the body cells that oxidizes it to get ATP’s.

As the amount of glucose is more in the blood than in the cells that consume it, an inward diffusion takes place. Because glucose is a water-soluble molecule that on its own cannot penetrate the membrane rapidly enough to support the metabolism of various cells, the mediated transport accelerates the inward flow of glucose.

Active Transport

The energy is provided to the system (‘pump’) to transport molecules in a direction opposite to a concentration gradient. It promotes movement in uphill direction, i.e., against the forces of passive diffusion. This involves expenditure of energy from ATP as substances are pumped against the concentration gradient.

The best example of active transport system in all animals is the maintenance of sodium and potassium gradients between cells and the surrounding extracellular fluid. Most of the animal cells need a high internal concentration of potassium ions for protein synthesis by the ribosomes and for some enzymatic activities.

The concentration of potassium ions is about 20–50 times more inside the cell as compared to the outside of the cell. On the other hand, sodium ion concentration is about 10 times more outside the cell as compared to the inside of the cell. Active transport maintains both these ionic gradients by transporting potassium ions into and the cell sodium ions out of the cell.

Bulk Transport

Bulk transport involves the movement of macro-nutrients, such as proteins, polysaccharides which can pass only through ruptured plasma membrane. Large molecules generally cross the membrane in bulk by endocytosis and exocytosis.

1. Endocytosis: The process by which material moves into the cell. It is of three types, namely phagocytosis(cell eating), potocytosis (cell drinking) and receptor-mediated endocytosis. All the three processes require energy.

• Phagocytosis: It is the process by which a cell called phagocyte takes in or engulfs or eats other cells or particles. The newly-formed phagosome then fuses with a lysosome whose hydrolytic enzymes digest the ’food’ inside. For example, white blood cells (leucocytes) that engulfs cellular debris and unwanted microbes in the blood. Other phagocytes are also present such as the macrophages found in connective tissue and liver sinusoids.

• Pinocytosis: The cell engulfs drops of fluid by pinching in and forming vesicles. Similarly to phagocytosis, pinocytosis is an unspecific process where the cell takes in any of the solutes that are dissolved in the liquid it encloses.
• Receptor-mediated endocytosis: It is a very selective process of importing substances into the cell. In this process, the receptor proteins present on depressed areas of the cell membrane (‘coated pits’) determines this specificity. Coat proteins cover the cytosolic surface of coated pits. The cell will only pick up an extracellular molecule when it binds to its specific receptor protein on the surface of the cell. When binding is done, the coated pit on which the bound receptor protein is situated then pinches in, to produce a coated vesicle. This coated vesicle now fuses with a lysosome to digest the engulfed substance and release it into the cytosol.

2. Exocytosis (Cell vomiting): Exocytosis is the process by which the intracellular vesicles in the cytoplasm fuse with the plasma membrane and release their contents into the surrounding medium.

Exocytosis takes place in many cells for the following purposes.

• Removes undigested material brought inside the cell by phagocytosis.
• Secrete substances like hormones, enzymes, etc.
• Transport a material wholly across a cellular barrier, for example, an immunoglobulin (IgA) or antibody is picked up on one side of the blood vessel wall by phagocytosis, transported across the cell and released by exocytosis.

Summary of movement methods across membranes

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Chapter 1 The Fundamental Unit Of Life Cell Wall

Cell wall is a rigid, non-living and freely permeable layer that lies outside the plasma membrane in plant cells. It protects the cell and its contents and determines the shape of the cell, and prevents desiccation of cells. It consists of a fibrous polysaccharide (carbohydrate) called cellulose.

Thus, the cell wall consists of minute cellulose fibres called microfibrils, which are cemented together by a mixture of polysaccharides. Each microfibril consists of numerous cellulose molecules bound together by pectins and hemicellulose.

Structure of Plant Cell Wall

Basically, the plant cell well consists of three layers and it is briefly explained as follows.

• Primary cell wall: A thin, flexible and extensible layer formed when the cell is growing. It provides the strength and flexibility required to allow the growth of cells.

• Secondary cell wall: A thick layer is formed inside the primary cell wall when the cell is fully grown. This layer is not found in all types of cells. Only some cells, such as the conducting cells in xylem have secondary wall consisting lignin that strengthens and protects the wall from water.
• Middle lamella: An outermost layer rich in pectins forms the interface between adjacent plant cells and cements them together.

Functions of a Cell Wall

• Cell wall makes the plant cell turgid. When water enters the vacuole through osmosis, the plant cell expands. The cell wall provides strength to the cell by providing turgidity to resist this expansion.
• Cell wall provides mechanical strength to the cell with the help of cellulose microfibrils. In xylem, lignin is present to provide additional strength. In collenchyma cells, extra amount of cellulose is present in the cell wall which increases the mechanical support.
• Cell wall is freely permeable to solvent and materials in solution.
• Cell wall consists of narrow pores known as pits through which very fine strands of cytoplasm known as plasmodesmata are able to pass. These intercellular connections permit the exchange of substances between the living cell contents.
• Middle lamella is a pectin layer that cements the cell walls of two adjoining cells together, which gives stability to the plants and also permits the plants to form plasmodesmata between cells. This layer is made up of calcium and magnesium pectates. This is the first layer that is formed and deposited during cytokinesis.

Plasmolysis

The phenomenon in which a living plant cell loses water through osmosis leading to shrinkage or contraction of the protoplasm away from the cell wall is called plasmolysis.

Chapter 1 The Fundamental Unit Of Life Nucleus (‘Brain of the Cell’)

The nucleus is membrane-bounded, centrally-located, spherical structure present in the eukaryotic cell. There are two nuclear membranes forming a nuclear envelope. There is a space between two nuclear membranes, which is connected to a system of membranes known as endoplasmic reticulum (ER).

The nuclear envelope makes the nucleus distinct from the cytoplasm. It also contains many pores called nuclear poresand it consists of the liquid ground substance called nucleoplasm. Nuclear pores permit the transfer of substances between the nucleoplasm and the cytoplasm.

The nucleoplasm consists of the nucleolus and chromatin material. The nucleolus is not bounded by any membrane and it is rich in protein and RNA (ribonucleic acid), and thus, it acts as a site for ribosome production. Ribosomes help in protein synthesis in the cytoplasm.

The chromatin is a thin, thread-like entangled mass of chromosome material and it consists of the genetic material DNA and proteins (i.e., histones). The chromatin is formed of repeating subunits called nucleosomes. Each nucleosome has a DNA molecule coiled around a disc of histones.

DNA is considered to be the blueprint of life as it contains all the required information for the cell to function, to grow and to reproduce. Genes are the discrete segments of DNA. During cell division, the chromatin material gets condensed into two or more thick ribbon-like chromosomes.

Functions of Nucleus

• Nucleus controls all metabolic activity of the cell.
• Nucleus regulates the cell cycle.
• Nucleus controls the transmission of hereditary characteristics from the parent to offspring.

Chapter 1 The Fundamental Unit Of Life Cytoplasm

Cytoplasm is the region of the cell located between the plasma membrane and nuclear envelope. Cytoplasm is a living, colourless, semi-liquid and homogenous substance. It occupies a major part of the cell and it is constantly moving.

Cytoplasm consists of a watery ground substance, called the cytosol, which contains the various cell organelles as well as other inclusions like insoluble wastes and storage products (glycogen, starch, etc.). Cell organelles are found embedded in the cytosol, and each of these has specific and important roles to play.

Cytosol forms the ground substance of the cytoplasm, in which all the cell organelles are embedded. It contains a system of protein fibres known as cytoskeleton. Cytosol is almost 90 per cent of water, which contains all the molecules and ions needed to support life. Cytosol serves as a store of vital chemicals, like amino acids, glucose, vitamins, ions, etc.

Endoplasmic Reticulum (ER)

ER is a membranous network enclosing a fluid-filled lumen that almost fills up the intracellular cavity. ER is connected to the outer membrane of the nucleus at one end, whereas the other end is connected to the plasma membrane. ER occurs in the form of three parts, namely cisternae (closed, fluid-filled sacs), vesicles and tubules.

There are two types of ER and they are explained as follows.

Rough endoplasmic reticulum (RER): Ribosomes are attached on its surface for protein synthesis.

Smooth endoplasmic reticulum (SER): No ribosomes are attached and it helps in secreting lipids.

Functions of ER

• ER acts as a supporting skeletal framework for the cell.
• ER helps in the passage of nuclear material between the adjoining cells.
• RER helps in the synthesis of proteins by ribosomes on their surface.
• In vertebrates, SER of liver helps in detoxification of various toxic or poisonous substances that enter the animal’s body through food, air or water.
• SER is involved in the biosynthesis of glycolipids, phospholipids and cholesterol.
• SER is involved in the synthesis of steroid hormones, like estrogen, testosterone and cortisol.
• RER produces hydrolytic enzymes of lysosomes. From RER, the hydrolytic enzymes are transported to Golgi apparatus where it gets included into lysosome.
• ER helps in the formation of plasma membrane and other cellular membranes. SER produces lipid molecules for cell membrane and gets inserted into SER membrane. RER is involved in the synthesis of protein molecules of cell membrane. In the process of glycosylation, small chains of sugars known as oligosaccharides are added to molecules of proteins and lipids at the level of Golgi apparatus.

Ribosomes

Ribosomes are dense, spherical and granular particles that are present freely in the cytosol or it remains studded to the RER. Ribosomes mainly consist of the ribonucleic acid (RNA) and proteins. Ribosomes are not bounded by membranes.

Function of Ribosomes

• Ribosomes play a crucial role in the synthesis of proteins.
• These are considered to be the factories of protein in a cell. Actually, one ribosome cannot perform protein synthesis.
• In 1963, Gric and Hall published the detailed role of polyribosome in protein synthesis and showed that active units are no individual ribosome, instead a group of these units are known as polyribosomes.

Types of Ribosomes

Basically, there are two types of ribosomes, such as 70S and 80S ribosomes. Here, S denotes Svedberg unit, which is the sedimentation coefficient that depicts how fast cell organelle sediments in an ultracentrifuge. Sedimentation coefficients cannot be additive.

80S ribosomes occur in eukaryotes, such as algae, fungi, higher plants and animals. In animals, the 80S ribosome is made up of a large 60S subunit and a small 40S subunit.

70S ribosomes are comparatively smaller and occur in prokaryotes such as bacteria. The 70S ribosomes are made up of a large 50S subunit and a small 30S subunit.

Interestingly, ribosomes found in mitochondria and chloroplasts of eukaryotes resemble to the ribosomes of prokaryotes and not to the 80S eukaryotic ribosomes.

Golgi Apparatus

Golgi apparatus is an arrangement of membrane-bounded, fluid-filled vesicles, vacuoles and flattened cisternae (closed sacs). Golgi apparatus originates from the membrane of the SER that in turn has originated from RER.

The proximal Golgi saccules (cisterna at cis face) are produced by fusion of ER-derived vesicles, whereas distal saccules (cisternae at trans face) are fully used for vesicle formation and vanish. Hence, Golgi saccules are renewed constantly and speedily.

Generally, the cisternae are stacked together in parallel. There are two faces of Golgi apparatus, such as Cis face of Golgi, where cisternae are formed and trans face of Golgi, where vesicles are budded off.

Functions

• Golgi apparatus acts as an assembly area for the storage, processing and packaging of various cellular secretions.
• It is involved in the synthesis of cell wall, plasma membrane and lysosomes.

Lysosomes

Lysosomes are small, spherical, single membrane-bound, sac-like structures uniformly distributed in the cytoplasm and it consists of digestive enzymes. These lysosomal enzymes are produced by RER.

Functions

• Lysosomes act as intracellular digestive system by destroying any foreign material that enters the cell and hence, these are called digestive bags. By doing this, they protect the cells from any harmful effect of foreign material such as from bacterial infection.
• Lysosomes remove the worn out cellular organelles by digesting them so that new replacements are done. By doing this, they remove the cell debris. Thus, lysosomes act as a type of garbage disposal system of the cell. These are also known as demolition squads, scavengers and cellular housekeepers.

• At the time of breakdown of cell structure, lysosomes may burst and the enzymes released eat up their own cells. Thus, lysosomes are also known as suicidal bags of a cell.

Mitochondria

The mitochondria are small bodies of varying shapes and size distributed in the cytoplasm. Each mitochondrion is enclosed in a double-membrane envelope. Outer membrane is having pores, whereas the inner membrane is thrown into folds called cristae, which are studded with tiny rounded bodies called F1 particles or oxysomes.

The internal cavity of the mitochondria is filled with a proteinaceous gel-like matrix that contains some smallsized ribosomes, a circular DNA molecule and phosphate granules.

Functions

• Mitochondria serve as the sites for cellular respiration. They utilize molecular oxygen from air to oxidize the carbohydrates and fats present in the cell to carbon dioxide and water vapour. Energy is released during oxidation and some part of this energy is used to form ATP (adenosine triphosphate). As mitochondria synthesizes energy-rich compounds hence they are called ’power house’ of the cell.
• Mitochondria can synthesize some of their own proteins, and DNA, due to which they are also considered as semi-autonomous organelles.

Plastids

Plastids are present in most of the plant cells, but absent in animal cells. The plastids have their own DNA and ribosomes and so they are self-replicating organelles similar to mitochondria. Plastids are mainly of three types and they are listed below.

• Chromoplasts: Coloured plastids (excluding green colour)
• Chloroplasts: Green-coloured plastids
• Leucoplasts: Colourless plastids

Functions

• Chloroplasts help in photosynthesis in which they manufacture food for the plant by trapping solar energy. These are called ‘kitchens of the cells’.
• Chromoplasts impart various colours to flowers and some leaves that helps in attracting the insects for pollination.
• Leucoplasts stores food in the form of starch, fats and protein.

Chloroplasts

Chloroplasts consist of a green pigment called chlorophyll, which helps in photosynthesis. Each chloroplast is enveloped by two unit membranes (Fig. 1.23). The two separate regions shown in the chloroplast are as follows.

• Grana are stacks of membrane-bounded, flattened discoid sacs (known as thylakoids) consisting of the chlorophyll molecules. These are the main functional units of chloroplasts. This is the site of light reaction during photosynthesis.
• Stroma is the homogeneous matrix in which grana are embedded. Stroma consists of various photosynthetic enzymes, starch grains, DNA and ribosomes. This is the site of dark reaction during photosynthesis.

Vacuoles

Vacuoles are fluid-filled or solid-filled; usually single membrane-bounded spaces. In animal cells, the vacuoles are rare, small and temporary. They store water, glycogen and proteins. Vacuoles serve as osmoregulatory organelles in protozoans and ingestion of nutrient material in amoeba and paramecium.

In plant cells, the vacuoles are large, distinct and permanent. In mature plant cells, the vacuole occupies almost 90 per cent volume of the cell and takes a central position. Due to this, the nucleus and other cell organelles are pushed near the cell wall. The vacuole is bounded by a membrane known as tonoplast and filled with a water solution called the cell sap.

Functions

• Vacuoles maintain the osmotic pressure in a cell.
• Vacuoles store toxic metabolic by-products or end products of plant cells.
• Vacuoles give turgidity and rigidity to the plant cells.

Peroxisomes

Peroxisomes are minute, single membrane-bounded, spherical organelles consisting of powerful oxidative enzymes. In peroxisomes, the inner contents are finely granular, but at times a crystalline core is visible by transmission electron microscope in the centre of peroxisomes.

This crystalline core is a crystallized protein known as catalase enzyme. Peroxisomes are usually found in kidney and liver cells.

Peroxisomes consists of catalase enzyme that catalyses the decomposition of hydrogen peroxide to water and oxygen. This gives the name ‘peroxisome’. As hydrogen peroxide is a by-product of some cell oxidations and is also highly toxic, so it must be eliminated from the cell.

Functions

Peroxisomes carry out some oxidative reactions like detoxification or removal of toxic substances from the cell.

Centrosome

Centrosome consists of two granule-like centrioles and it is not covered by any membrane. Centrioles are hollow and cylindrical structures that are made up of microtubules. Centrosomes are present only in animal cells. In plant cells, the polar caps perform functions similar to that of the centrioles.

Functions

Centrosome is involved in cell division in animal cells. At the time of cell division, centrioles move to the poles of cells and helps in the formation of spindle.

Chapter 1 The Fundamental Unit Of Life Classroom Corner Fill In The Blanks

Question 1. Scientist credited with the discovery of cell __________.
Answer. Robert Hooke

Question 2. World’s largest single-celled organism __________.
Answer. Caulerpa taxifolia

Question 3. Largest cell in the human body __________.
Answer. Ovum

Question 4. Smallest cell in the human body __________.
Answer. Sperms

Question 5. Proposed cell theory in animals __________.
Answer. Theodor Schwann in 1839

Question 6. Father of microbiology __________.
Answer. Anton van Leeuwenhoek

Question 7. Energy stored in mitochondria is in the form of __________.
Answer. ATP (Adenosine triphosphate)

Question 8. Groups of ribosomes in the cell __________.
Answer. Polysomes

Question 9. Plastids present in flowers and fruits _______.
Answer. Leucoplasts

Question 10. Considered as kitchen of cell __________.
Answer. Chloroplasts

Chapter 1 The Fundamental Unit Of Life Match The Columns

Question 1.

1. A-3, B-5, C-1, D-2, E-4
2. A-1, B-2, C-3, D-4, E-5
3. A-5, B-4, C-3, D-2, E-1
4. A-4, B-1, C-2, D-5, E-3

Answer. 1. A-3, B-5, C-1, D-2, E-4

Question 2.

Select the correct option.

1. A-1, B-2, C-3, D-4, E-5
2. A-5, B-4, C-3, D-2, E-1
3. A-4, B-5, C-1, D-3, E-2
4. A-5, B-3, C-1, D-4, E-2

Answer. 3. A-4, B-5, C-1, D-3, E-2

Question 3.

Select the correct option.

1. A-3, B-2, C-3, D-1, E-5
2. A-5, B-4, C-1, D-2, E-3
3. A-4, B-5, C-1, D-3, E-2
4. A-4, B-3, C-1, D-5, E-2

Answer. 3. A-4, B-5, C-1, D-3, E-2

Question 4.

Select the correct option.

1. A-1, B-2, C-3, D-4, E-5
2. A-5, B-4, C-1, D-2, E-3
3. A-4, B-5, C-1, D-3, E-2
4. A-4, B-5, C-3, D-1, E-2

Answer. 3. A-4, B-5, C-1, D-3, E-2

Question 5.

Select the correct option.

1. A-1, B-2, C-3, D-4
2. A-1, B-4, C-3, D-2
3. A-3, B-4, C-1, D-2
4. A-2, B-4, C-3, D-1

Answer. 3. A-3, B-4, C-1, D-2

Chapter 1 The Fundamental Unit Of Life Long Answer Type Question And Answers

Question 1. Discuss the differences between cell wall and plasma membrane.
Answer.

The differences between cell wall and plasma membrane:

The Fundamental Unit Of Life

Question 2. How does an amoeba obtain its food?
Answer.

An Amoeba Obtain Its Food As Follows:

Amoeba obtains food using temporary fingerlike extensions on the cell surface which fuse over the food particle forming a food-vacuole. Complex substances are broken down into simpler ones inside the food vacuole which then diffuses into the cytoplasm. The remaining undigested material is moved to the surface of the cell and is thrown out resulting in excretion.

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Cell The Fundamental Unit Of Life

Question 3. Discuss the differences between mitochondria and chloroplast.
Answer.

The differences between mitochondria and chloroplast:

Question 4. Explain the functions of lysosomes.
Answer.

The functions of lysosomes:

• Lysosomes act as intracellular digestive system by destroying any foreign material that enters the cell and hence, these are called digestive bags. By doing this, they protect the cells from any harmful effect of foreign material such as from bacterial infection.
• Lysosomes remove the worn out cellular organelles by digesting them so that new replacements are done. By doing this, they remove the cell debris. Thus, lysosomes act as a type of garbage disposal system of the cell. These are also known as demolition squads, scavengers and cellular housekeepers.
• At the time of breakdown of cell structure, lysosomes may burst and the enzymes released eat up their own cells. Thus, lysosomes are also known as suicidal bags of a cell.

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Question 5. Discuss the functions and types of ribosomes.
Answer.

The functions and types of ribosomes:

• Function: Ribosomes play a crucial role in the synthesis of proteins. These are the factories of protein in a cell. One ribosome cannot perform protein synthesis. In 1963, Gric and Hall published the detailed role of polyribosome in protein synthesis and showed that active units are no individual ribosome, instead a group of these units are known as polyribosomes.
• Types of ribosomes: Basically, there are two types of ribosomes, such as 70S and 80S ribosomes. Here, S denotes Svedberg unit, which is the sedimentation coefficient that depicts how fast cell organelle sediments in an ultracentrifuge. Sedimentation coefficients cannot be additive.

Question 6. Discuss the differences between smooth endoplasmic reticulum and rough endoplasmic reticulum.
Answer.

The differences between smooth endoplasmic reticulum and rough endoplasmic reticulum:

Question 7. Discuss the structure of nucleus.
Answer.

The structure of nucleus:

The nucleus is membrane-bounded, centrally located, spherical structure present in the eukaryotic cell. There are two nuclear membranes forming a nuclear envelope. There is a space between two nuclear membranes, which is connected to a system of membranes known as endoplasmic reticulum (ER).

The nuclear envelope makes the nucleus distinct from the cytoplasm. It also contains many pores called nuclear pores and consists of the liquid ground substance called nucleoplasm. Nuclear pores permit the transfer of substances between the nucleoplasm and the cytoplasm.

The nucleoplasm consists of the nucleolus and chromatin material. The nucleolus is not bounded by any membrane, and is rich in protein and RNA (ribonucleic acid), and thus, it acts as the site for ribosome production. Ribosomes help in protein synthesis in the cytoplasm.

Question 8. Discuss the differences between nucleus and nucleoid.
Answer.

The differences between nucleus and nucleoid:

Chapter 1 The Fundamental Unit Of Life Short Answer Type Question And Answers

Question 1. Discuss the structure and function of the plasma membrane.
Answer.

The structure and function of plasma membrane:

Delicate, elastic, and selectively permeable membrane. The membrane is almost made up of 75% phospholipids. It consists of proteins, cholesterol and polysaccharides.

Membrane is a semipermeable or selectively permeable membrane. It gives shape to cell and regulates the movement of molecules in and out of the cell.

Fundamental Unit Of Life Question Answer

Read And Learn More NEET Foundation Short Answer Questions

Question 2. Define diffusion and osmosis.
Answer.

Diffusion And Osmosis:

Diffusion is the net movement of solute particles from a region of high concentration to the region of low concentration. Osmosis is the passage of water or solvent from a region of high solvent concentration through a semipermeable membrane to a region of low solvent concentration.

Question 3. How do substances like CO₂ and water move in and out of the cell? Discuss.
Answer.

Movement Of substances like CO₂ and water move in and out of the cell:

The substances like CO₂ and water move in and out of a cell through the process called diffusion from the region of concentrated region to low concentrated one. When the concentration of carbon dioxide and water is higher in external environment than that inside the cell, CO₂ and water moves inside the cell. When the concentration outside the cell is low but it is high inside the cell, they move outwards.

Question 4. Discuss the difference between endocytosis and exocytosis.
Answer.

The difference between endocytosis and exocytosis:

Question 5. Why the plasma membrane is called a selectively permeable membrane?
Answer.

The plasma membrane is called a selectively permeable membrane:

Plasma membrane is called a selectively permeable membrane because it regulates the movement of substances from within to outside of the cell. This means that the plasma membrane allows the entry of some substances while preventing the movement of some other substance.

Question 6. Discuss the differences between active transport and diffusion.
Answer.

The differences between active transport and diffusion:

Fundamental Unit Of Life Question Answer

Question 7. Discuss the function of Golgi apparatus.
Answer.

The function of Golgi apparatus:

• Golgi apparatus acts as an assembly area for the storage, processing and packaging of various cellular secretions.
• It is involved in the synthesis of cell wall, plasma membrane and lysosomes

Question 8. Discuss why mitochondria is known as the power house of the cell.
Answer.

Mitochondria is known as the power house of the cell:

Mitochondria are known as the powerhouse of cells because the energy required for various chemical activities needed to support life is released by mitochondria in the form of ATP (Adenosine triphosphate) molecules.

Question 9. What are dictyosomes?
Answer.

Dictyosomes:

In plant cells, Golgi apparatus is present in the form of freely distributed subunits called dictyosomes.

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Question 10. Why are lysosomes known as suicide bags?
Answer.

Lysosomes known as suicide bags:

Lysosomes are called suicide bags because in case of any disturbance of their cellular metabolism, they release their own enzymes to digest their own cell.

Question 11. Where are proteins synthesized inside the cell?
Answer.

The proteins are synthesized in the ribosome.

Question 12. Discuss the characteristic features of peroxisomes and lysosomes.
Answer.

The characteristic features of peroxisomes and lysosomes:

Question 13. What are the characteristic differences between nucleus and nucleolus?
Answer.

The characteristic differences between nucleus and nucleolus:

Question 14. What would happen to the life of a cell if there was no Golgi apparatus?
Answer.

Golgi apparatus performs the function of a storage modification and packaging of products. If Golgi apparatus is not there, then the materials synthesized by cell will not be packaged and transported.

Question 15. Why the plasma membrane is called a selectively permeable membrane?
Answer:

The plasma membrane is called a selectively permeable membrane:

Plasma membrane is called a selectively permeable membrane because it regulates the movement of substances from within to outside of the cell. Selectively permeable describes the extreme selective nature of a membrane, wherein it specifically chooses certain molecules to pass. So, plasma membrane allows the entry of some substances while preventing the movement of some solutes.

Question 16. Who proposed the model called fluid mosaic model to explain the structure of functional cell membranes or plasma membranes?
Answer:

The model called fluid mosaic model to explain the structure of functional cell membranes or plasma membranes is proposed by

S. J. Singer and G. L. Nicolson (1972).

Question 17. Can you name the two organelles we have studied that contain their own genetic material?
Answer:

Mitochondria and plastids.

Question 18. If the organization of a cell is destroyed due to some physical or chemical influence, then what will happen?
Answer:

The organization of a cell is destroyed due to some physical or chemical influence:

If the organization of a cell is destroyed due to some physical or chemical influence then the cell will not be able to perform its basic functions, like digestion, excretion, respiration, etc. This may stop all the life activities and may come to an end.

Question 19. What is diffusion?
Answer:

Diffusion:

Diffusion is the net movement of solute particles from a region of high concentration to the region of low concentration.

Question 20. What would happen if the plasma membrane ruptures or breaks down?
Answer:

The plasma membrane ruptures or breaks down then

The cell will not be able to exchange material from its surroundings by diffusion. Due to this process, the protoplasmic material will disappear and the cell will die.

Chapter 1 The Fundamental Unit Of Life Multiple Choice Question And Answers

Direction: Choose the correct option for each questions. There is only one correct response for each question.

Question 1. The study of cell structure under microscope is

1. Cytology
2. Cell biology
3. Cytochemistry
4. Anatomy

Answer. 1. Cytology

Question 2. Which of the following does not have cellular structure?

1. PPLO
2. Rickettsia
3. Viruses
4. Archaebacteria

Answer. 3. Viruses

Question 3. The smallest animal egg is of

1. Ostrich
2. Duck
3. Human female
4. Hen

Answer. 3. Human female

Read and Learn More NEET Foundation Multiple Choice Questions

Question 4. Protoplasm without nucleus is called

1. Cytoplasm
2. Ectoplasm
3. Protoplasm
4. Endoplasm

Answer. 1. Cytoplasm

Question 5. Hardness of woody tissue is due to

1. Cellulose
2. Silica
3. Lignin
4. Suberin

Answer. 3. Lignin

Question 6. A well-organized nucleus is present in

1. Prokaryotes
2. Eukaryotes
3. Bacteria
4. Both (a) and(c)

Answer. 2. Eukaryotes

Question 7. Human egg is larger than human sperm because it has

1. Larger nucleus
2. More membrane
3. More cytoplasm
4. All of these

Answer. 3. More cytoplasm

Question 8. Within a cell, the site of respiration (oxidation) is the

1. Ribosome
2. Golgi apparatus
3. Mitochondria
4. Endoplasmic reticulum

Answer. 3. Mitochondria

Question 9. Which of the following is called ‘Suicidal bag’?

1. Centrosome
2. Lysosome
3. Mesosome
4. Chromosome

Answer. 2. Lysosome

Question 10. Double membrane is absent in

1. Mitochondrion
2. Chloroplast
3. Nucleus
4. Lysosome

Answer. 4. Lysosome

Question 11. The cell organelle found only in plant is

1. Golgi apparatus
2. Mitochondria
3. Plastids
4. Ribosomes

Answer. 3. Plastids

Question 12. Organisms lacking nucleus and membrane-bound organelles are called

1. Diploids
2. Prokaryotes
3. Haploids
4. Eukaryotes

Answer. 2. Prokaryotes

Question 13. Animal cell is limited by

1. Plasma membrane
2. Shell membrane
3. Cell wall
4. Basement membrane

Answer. 1. Plasma membrane

Question 14. The network of endoplasmic reticulum is present in the

1. Nucleus
2. Nucleolus
3. Cytoplasm
4. Chromosome

Answer. 3. Cytoplasm

Question 15. Lysosome are reservoirs of

1. Fat
2. RNA
3. Secretory glycoprotein
4. Hydrolytic Enzymes

Answer. 4. Hydrolytic Enzymes

Question 16. The membrane surrounding the vacuole of a plant cell is called

1. Tonoplast
2. Plasma membrane
3. Nuclear membrane
4. Cell wall

Answer. 1. Tonoplast

Question 17. Cell secretion is done by

1. Plastids
2. ER
3. Golgi apparatus
4. Nucleolus

Answer. 3. Golgi apparatus

Question 18. Centrioles are associated with

1. DNA synthesis
2. Reproduction
3. Respiration
4. Spindle formation

Answer. 4. Spindle formation

Question 19. Ribosomes are the centre for

1. Respiration
2. Photosynthesis
3. Protein synthesis
4. Fat synthesis

Answer. 3. Protein synthesis

Question 20. Plastid which can form all other types of plastids is

1. Leucoplast
2. Amyloplast
3. Chloroplast
4. Chromoplast

Answer. 1. Leucoplast

Question 21. A plant cell becomes turgid due to

1. Plasmolysis
2. Exosmosis
3. Endosmosis
4. Electrolysis

Answer. 3. Endosmosis

Question 22. Solute concentration is higher in the external solution

1. Hypotonic
2. Hypertonic
3. Isotonic
4. None of these

Answer. 2. Hypertonic

Question 23. A cell placed in hypertonic solution will

1. Shrink
2. Show plasmolysis
3. Swell up
4. No change in shape or size.

Answer. 3. Swell up

Question 24. The radiant energy of sunlight is converted to chemical energy and is stored as

1. AMP
2. ATP
3. ADP
4. APP

Answer. 2. ATP

Question 25. Which of the following organelle does not have membrane?

1. Ribosome
2. Nucleus
3. Chloroplast
4. Mitochondria

Answer. 1. Ribosome

Question 26. Root hair absorbs water from soil through

1. Osmosis
2. Active transport
3. Diffusion
4. Endocytosis

Answer. 1. Osmosis

Question 27. The number of lenses in compound light microscope is

1. 3
2. 2
3. 4
4. 1

Answer. 2. 2

Question 28. Identify the human cells which lack nucleus

1. Platelets
2. WBC
3. RBC
4. Nerve cells

Answer. 3. RBC

Question 29. Which of the following cellular part possess a double membrane?

1. Nucleus
2. Chloroplast
3. Mitochondrion
4. All of the above

Answer. 4. All of the above

Question 30. Cristae and oxysomes are associated with

1. Mitochondria
2. Plastids
3. Golgi apparatus
4. Plasma membrane

Answer. 1. Mitochondria

Question 31. Genetic information is stored in

1. RNA
2. DNA
3. Ribosomes
4. Lysosomes

Answer. 2. DNA

Question 32. Animal cells have

1. Either few small vacuoles or may be absent
2. One large vacuole
3. Many large vacuoes
4. Few small vacuoles

Answer. 1. Either few small vacuoles or may be absent

Question 33. Cell organelle that acts as supporting skeletal framework of the cell is

1. Golgi apparatus
2. Nucleus
3. Mitochondria
4. ER

Answer. 4. ER

Question 34. What would happen if lysosomes get ruptured inside the cells in which they are present?

1. Cells will swell
2. Cells will die
3. Cells will shrink
4. Nothing would happen

Answer. 2. Cells will die

Question 35. The cell wall of plant is chiefly composed of

1. Hemicellulose
2. Phospholipids
3. Cellulose
4. Proteins

Answer. 3. Cellulose

Question 36. Which of the following are characteristics of unicellular organisms?

(1) There is no division of labour.

(2) Life span of organism is long.

(3) Reproduction consumes the whole cell.

(4) Single cell performs one or few activities of the organism.

Select the correct option.

1. (1) and (2)
2. (2) and (3)
3. (1) and (3)
4. (4) and (1)

Answer. 3. (1) and (3)

Question 37. Which of the following are properties of a light microscope?

(1) It uses beams of electrons to illuminate objects.

(2) It uses beams of light to illuminate the object.

(3) Internal vacuum is not required.

(4) It uses glass lenses.

Select the correct option.

1. (1) and (2)
2. (2) and (3)
3. (2), (3) and (4)
4. (1), (3) and (4)

Answer. 3. (2), (3) and (4)

Question 38. Which of the following are characteristics of prokaryotic cells?

(1) Nucleolus is absent.

(2) It contains single chromosome.

(3) Cell division occurs by mitotic or meiotic cell division.

(4) Size of cell is generally large (5.100 mm).Select the correct option.

1. (1) and (4)
2. (1) and (2)
3. (1), (2) and (3)
4. (3) and (4)

Answer. 2. (1) and (2)

Question 39. Which of these are not the features of organelles?

(1) They may be external or internal to body of an organism.

(2) They coordinate to produce the cell.

(3) They are found in all eukaryotic cells.

(4) They are macroscopic.

Select the correct option.

1. (1) and (2)
2. (4) and (3)
3. (1) and (4)
4. (2) and (3)

Answer. 3. (1) and (4)

Question 40. Which of these options are not functions of ribosomes?

(1) It helps in the manufacture of protein molecules.

(2) It helps in the manufacture of enzymes.

(3) It helps in the manufacture of hormones.

(4) It helps in the manufacture of starch molecules.

Select the correct option:

1. (1) and (2)
2. (2) and (3)
3. (3) and (4)
4. (4) and (1)

Answer. 3. (3) and (4)

Question 41. Osmosis __________________

(1) is the spontaneous movement of water molecules through a selective permeable membrane (for example, plasma membrane).

(2) can occur in any medium.

(3) occurs only in liquid medium.

(4) does not require semipermeable membrane.

Select the correct option.

1. (1) and (2)
2. (2) and (3)
3. (3) and (4)
4. (4) and (1)

Answer. 4. (4) and (1)

Question 42. Endocytosis is __________________

(1) intake of extra-cellular fluid, droplets and macromolecules.

(2) intake of extracellular particles.

(3) growth of plasma membrane around the particle as pseudopodia.

(4) a nutritive process.

Select the correct option.

1. (1) and (2)
2. (2) and (3)
3. (3) and (4)
4. (4) and (1)

Answer. 4. (4) and (1)

Question 43. Nucleus __________________

(1) is without a covering membrane.

(2) represents the whole eukaryotic complex that contains the genetic information.

(3) is covered by a two membrane envelope.

(4) is a component of nucleoid.

Select the correct option.

1. (1) and (2)
2. (2) and (3)
3. (3) and (4)
4. (4) and 1

Answer. 2. (2) and (3)

Question 44. Chloroplasts __________________

(1) are green plastids

(2) are sites of photosynthesis

(3) are non-green coloured plastids

(4) do not contain lamellae

Select the correct option.

1. (1) and (2)
2. (2) and (3)
3. (3) and (4)
4. (4) and (1)

Answer. 1. (1) and (2)

Question 45. Chromosomes are made up of ______________

(1) DNA

(2) Protein

(3) O₂

(4) CO₂

Select the correct option.

1. (1) and (2)
2. (2) and (3)
3. (3) and (4)
4. (4) and (1)

Answer. 1. (1) and (2)

Question 46. Find out the false statement from the following.

(1) Cytoplasm is also called protoplasm.

(2) Mitochondria is the powerhouse of the cell.

(3) Golgi apparatus is involved with the formation of lysosomes.

(4) Ribosomes do not help in protein synthesis.

Select the correct option.

1. (1) and (2)
2. (1) and (3)
3. (3) and (4)
4. (1) and (4)

Answer. 4. (1) and (4)

Question 47. Who amongst the following were contributors to the cell theory?

(1) Theodor Schwann

(2) Matthias Schleiden

(3) Robert Hooke

(4) Robert Brown

Select the correct option.

1. (1) and (2)
2. (2) and (3)
3. (3) and (4)
4. (1) and (4)

Answer. 1. (1) and (2)

Question 48. Elephants eat grass and both have cells.

Read the following sentences regarding cells, and identify the correct ones.

(1) Grass cells have cell walls and vacuoles.

(2) Glass cells have cilia and chloroplast.

(3) Elephant cells are bigger than grass cells.

(4) Elephant cells have cell membrane and mitochondria.

Select the correct option.

1. (1) and (2)
2. (2) and (3)
3. (3) and (4)
4. (1) and (4)

Answer. 4. (1) and (4)

Question 49. A mature plant cell has

(1) Cell wall

(2) Plastids

(3) Centrioles

(4) Prominent golgi apparatus

Select the correct option.

1. (1) and (2)
2. (2) and (3)
3. (3) and (4)
4. (1) and (4)

Answer. 1. (1) and (2)

Question 50. Mitochondria

(1) Powerhouse of the cell

(2) Green in colour

(3) Performs oxidation of food.

(4) Consumes CO₂ and liberates O₂.

Select the correct option.

1. (1) and (2)
2. (2) and (3)
3. (1) and (3)
4. (1) and (4)

Answer. 3. (1) and (3)

Question 51. A major site for synthesis of lipids is

1. Rough endoplasmic reticulum
2. Smooth endoplasmic reticulum
3. Symplast
4. Nucleoplasm

Answer. 2. Smooth endoplasmic reticulum

Question 52. Which structure perform the function of mitochondria in bacteria?

1. Nucleoid
2. Ribosomes
3. Cell wall
4. Mesosomes

Answer. 4. Mesosomes

Question 53. The important site for the formation of glycoproteins and glycolipids is

1. Golgi apparatus
2. Plastid
3. Lysosome
4. Vacuole

Answer. 1. Golgi apparatus

Question 54. In eubacteria, cellular component that resembles eukaryotic cells is

1. Nucleus
2. Ribosomes
3. Cell wall
4. Plasma membrane

Answer. 4. Plasma membrane

Question 55. Peptide synthesis inside a cell takes place in

1. Mitochondria
2. Chromoplast
3. Ribosomes
4. Chloroplast

Answer. 3. Ribosomes

Question 56. Ribosomal RNA is actively synthesized in

1. Lysosomes
2. Nucleolus
3. Nucleoplasm
4. Ribosomes

Answer. 2. Nucleolus

Question 57. Nuclear membrane is absent in

1. Penicillium
2. Agaricus
3. Volvox
4. Nostoc

Answer. 4. Nostoc

Question 58. True nucleus is absent in

1. Anabaena
2. Mucor
3. Vaucheria
4. Volvox

Answer. 1. Anabaena

Question 59. Which of the following is not an inclusion body found in prokaryotes?

1. Phosphate granule
2. Cyanophycean granule
3. Glycogen granule
4. Polysome

Answer. 4. Polysome

Question 60. Which of the following are not membrane-bound?

1. Ribosome
2. Lysosome
3. Mesosomes
4. Vacuole

Answer. 1. Ribosome

Question 61. Which of the following structures is not found in prokaryotic cell?

1. Ribosomes
2. Mesosomes
3. Plasma membrane
4. Nuclear envelope

Answer. 4. Nuclear envelope

Question 62. Cell organelle containing hydrolytic enzymes is

1. Microsome
2. Ribosome
3. Mesosome
4. Lysosome

Answer. 4. Lysosome

Question 63. Who proposed the fluid mosaic model of plasma membrane?

1. Camillo Golgi
2. Schleiden and Schwann
3. Singer and Nicolson
4. Robert Brown

Answer. 3. Singer and Nicolson

Question 64. What is a tonoplast?

1. Outer membrane of mitochondria.
2. Inner membrane of chloroplast.
3. Membrane boundary of the vacuole of plant cells.
4. Cell membrane of plant cell.

Answer. 3. Membrane boundary of the vacuole of plant cells.

Question 65. Satin used to visualize mitochondria is

1. Fast green
2. Safranin
3. Acetocarmine
4. Janus green

Answer. 4. Janus green

Question 66. Who refined the cell theory?

1. Schleiden
2. Schwann
3. Rudolf Virchow
4. Robert Hooke

Answer. 3. Rudolf Virchow

Question 67. Example/s of prokarotic cells is/are

1. Bacteria
2. Kidney cells
3. Interstitial cells
4. Cork cells

Answer. 1. Bacteria

Question 68. In prokaryotic cells, ______ is present instead of nucleus.

1. Nucleosome
2. Nuclear pore
3. Nuclear envelope
4. Nucleoid

Answer. 4. Nucleoid

Question 69. A science student wants to view the plasma membrane and other cell organelles of a rabbit cell. Which of the following microscope should the student use?

1. Light microscope
2. Compound microscope
3. Dissecting microscope
4. Electron microscope

Answer. 4. Electron microscope

Question 70. Cell theory states that cells are structural and fundamental units of

1. Plants
2. Animals
3. Both plants and animals
4. Only microorganisms

Answer. 3. Both plants and animals

Question 71. The energy currency of cell is

1. Mitochondria
2. ATP
3. FAD
4. Glucose

Answer. 2. ATP

Question 72. Which of the following organelles is enclosed in a single membrane?

1. Nuclei
2. Lysosomes
3. Chloroplast
4. Mitochondria

Answer. 2. Lysosomes

Question 73. The electron microscope was developed by

1. Huxley
2. Knoll and Ruska
3. Purkinje
4. Robert Hooke

Answer. 2. Knoll and Ruska

Question 74. The idea of ‘Omnis Cellula e Cellula’ was given by

1. Scheiden
2. Rudolf Virchow
3. Purkinje
4. Schwann

Answer. 2. Rudolf Virchow

Question 75. The size of an organism is dependent on

1. Size of the cell
2. Number of cell
3. Both (a) and (b)
4. Shape of cells

Answer. 3. Both (a) and (b)

NEET Foundation Chemistry Notes For Chapter 3 Atoms And Molecules

For ages, ancient Indian and Greek philosophers wondered about the unseen and unknown form of matter. Around 500 bc, India, the idea of divisibility of matter took shape.

Maharishi Kanad, An Indian philosopher, suggested that if we kept on diving matter (padarth), we will get smaller and smaller particles and ultimately, a time will come when the further division will not be possible and we will obtain the smallest particle of the matter.

He called these particles as parmanu. Pakudha Katyayama, another Indian philosopher, postulated that these exists in the combined form which is the reason for the varied forms of matter.

Read and Learn More: NEET Foundation Notes

All matters are made up of atoms. Atoms do not exist independently. Atoms are further divided into ions and molecules. Molecules and ions collectively in large number forms matter.

NEET Foundation Chemistry Notes For Chapter 3 Atoms And Molecules Laws of Chemical Combination

A molecule is a group of atoms that are chemically bonded together and held by intermolecular force. The tiniest particle of an element which exists independently by inheriting all the characteristics of that substance is called a molecule.

Matter transforms from one state to the other under certain circumstances. This phenomenon takes place due to combination of two types of matter. This process of combination of different elements to form compounds takes place under certain rule.

Chemistry is the study of the transformation of matter from one form to the other. These transformations often occur as a result of the combination of two different types of matter. The combination of different elements to form compounds is governed by certain basic rules. These rules are referred to as laws of chemical combination.

The rules are known as laws of chemical combination. The rules that aid the chemical combinations of elements are discussed below.

Law of Conservation of Mass

Law of conservation of mass was given by Antoine Lavoisier and verified by Landolt. According to this law, during a chemical reaction matter is neither created nor destroyed, it may change from one form to other. After a chemical reaction the total mass of materials is same as the total mass before reaction.

Greek Philosopher Democritus (460–370 bc) and Leucippus also worked on the idea of division of matter. According to them sub-division of matter is limited. Democritus named the individual particles as ’atoms’ meaning indivisible.

Law of Constant or Definite Proportion

Law of definite proportion was given by Joseph Proust who was a French chemist. According to the law, in a given compound the proportion of elements by weight will always remain same irrespective of the methods of preparation.

Law of Multiple Proportions

Law of multiple proportions was given by Dalton in 1803 and verified by Berzelius. According to this law, when more than one compound is formed by combining two elements the masses of these elements in the reaction are in the ratio of small whole numbers.

Law of Equivalent Proportion or Law of Reciprocal Proportion

Law of equivalent proportion was given by Ritcher. According to this law, the weights of two or more elements which separately react with same weight of a third element are also the weights of these elements which react with each other or in simple multiple of them.

Gay-Lussac’s Law of Gaseous Volumes

Gay-Lussac’s law of Gaseous volumes was given by Gay–Lussac in 1808 and is applicable only for gases. This law was based on experimental observation done by Gay-Lussac. According to the law, the production of gases takes place in a simple ratio by volume, temperature and pressure being constant.

It can be treated as another form of law of definite proportions. The only difference between these two is that Gay Lussac’s Law is stated with respect to volume while law of definite proportions is stated with respect to mass.

Avogadro’s Law

Avogadro in 1811 gave Avogadro’s law which states that equal volume of gas contains equal number of molecules, temperature and pressure being constant.

Atoms And Molecules Notes

Example: 2 litres of hydrogen contains same number of molecules as 2 litres of oxygen, temperature and pressure being constant of both gases.

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NEET Foundation Chemistry Notes For Modern Periodic Table

In recent times, IUPAC (International Union of Pure and Applied Chemistry) approves names of elements. Many of the symbols are the first one or two letters of the element’s name in English.

The first letterof a symbol is always written as a capital letter (uppercase) and the second letter as a small letter (lowercase).

NEET Foundation Chemistry Notes For Chapter 3 Atoms And Molecules About Molecule

Molecules of elements: A molecule is made up of atoms. Molecules of elements are made up of same types of atoms. Some molecules may be made up of a single atom.

Example: Helium, But in most of the cases the molecules are made up of two or more atoms. The number of atoms needed to make a molecule is called as atomicity of that element.

Molecules of compounds: A compound is a molecule made up of 2 or more different types of atoms.

Example: 1 molecule of water contains 2 molecules of hydrogen and 1 molecule of oxygen. Similarly, 1 molecule hydrochloric acid contains 1 molecule of hydrogen and 1 molecule of chlorine.

Molecules of some compounds

Atomicity

It refers to the number of atoms present in one molecule of an element or substance.

For example one molecule of HCl has one atom of hydrogen and one atom of chlorine. So, the atomicity of HCl is 2. The molecules are called Monatomic, Diatomic or triatomic depending on the number of atoms present in it.

Atomicity of some elements

Ion

An ion is defined as an electrically charged atom or group of atoms formed by the loss or gain of one or more electrons. A positive ion is created by electron loss and a negative ion is created by an electron gain.

Example: Air conditioners, fluorescent lamps and printers, etc., are generators of positive ion or cation, which is very harmful for health.

On the other hand negative ions are in abundance in forests. The natural negative ions neutralize the harmful positive ions in the atmosphere as they attract dust particles and other pollutants.

Positively charged ion is called cation and a negative ion called anion.

Some common, simple and polyatomic ions

NEET Foundation Chemistry Notes For Chapter 3 Atoms And Molecules Writing Chemical Formulae

The chemical formula of a compound represents its chemical composition. A chemical formula essentially indicates 2 things:

• The elements which constitutes that compound and the number of each element in it.
• The number of each constituent.

The atoms of the elements are indicated by the symbols and the number is indicated as a subscript with the symbol.

Example: In CO₂, C and O are the symbols of carbon and oxygen respectively while 2 indicates that 2 atoms of oxygen have been used in the compound.

There are three fundamental rules of writing chemical formula:

• The valencies of the elements must balance.
• When a compound contains both metal and non-metal elements the name of metal comes first.Example: Sodium Chloride (NaCl)
• In polyatomic ion compounds, the ion is enclosed in bracket before writing the formula to indicate the ratio. In case the ion is mono-atomic then bracket is not required.

Formula of Simple Compound

For writing a formula for the simple compound the symbol and the valencies of the atoms are written and then the valencies are crossed with the atom to balance the formula.

Illustration 1: Figure explains that the valency of carbon atom is 4 while that of chlorine is 1. To balance the formula the valency is crossed with the symbol to write the correct formula.

Formulation of Ionic Compounds

When writing a formula with ionized atoms it should be kept in mind that the cation and anion should be balanced.

Illustration 2: The figure explains that the Aluminum atom has 3 positive charges while Oxygen atom has 2 negative charges. To balance this, 2 atoms of Al and 3 atoms of O are used to form neutralized Al₂O₃.

NEET Foundation Chemistry Notes For Chapter 3 Atoms And Molecules Molecular Mass and Mole Concept

The molecular mass is the sum of atomic masses of all the atoms present in the molecule. The relative mass of molecule is expressed in atomic mass unit (u). The formula unit mass is the sum of the atomic masses of all atoms in a formula unit of a compound. It is calculated in the way we calculate the molecular mass. We use formula unit for those substances which are made up of ions.

Atomic Mass Unit (u) is defined as a unit of mass used to express atomic and molecular weights, equal to one twelfth of the mass of an atom of carbon-12.

Example: Atomic mass of carbon is 12.0 u while atomic mass of oxygen atom is 16.0 u, so the molecular mass of 1 molecule of CO₂ will be 44.0 u (12.0 u + 16.0 u + 16.0 u).

Mole Concept

It is not necessary that all the substances are formed by joining of atoms. In practice 2 or more molecules can also be mixed to get new substances.

Example: 2 molecules of hydrogen combine with 1 molecule of oxygen to make 2 molecules of water. It is evident from this example that 2 hydrogen and 1 oxygen is the minimum required unit to create molecule of water.

In other words mole is the number of atoms in 12 grams of C-12. This is the basic counting unit for scientists.

1. The number of atoms in 12 gram of C-12 is 6.022 × 10²³. This is called Avogadro’s number.

2. When Avogadro number is divided by mole it becomes a constant known as Avogadro’s constant denoted by N_A ⋅ N_A = 6.02 × 10²³ mol^-1.

Example: Atomic mass of carbon (C) is 12 u.

This means 12 u C has only 1 atom of carbon.

12 g carbon has 1 mole atoms of carbon

Therefore, 12 gram carbon has 6.02 × 10²³ atoms of carbon.

Similarly, atomic mass of He (Helium) is 4 u

4 u He will have only 1 atom of He.

4 gram of He will have 1 mole atoms of He.

Therefore, 4 grams He has 6.02 × 10²³ atoms of He.

Molar Mass

Mass of 1 mole of substance is called molar mass.

Example: Atomic mass of He is 4 u

So 4 u of He = 1 atom of He

So 4 gram of He = 1 mole atom of He

Therefore, molar mass of He is 4 gram.

NEET Foundation Chemistry Notes For Chapter 3 Atoms And Molecules Fill In the Blanks

Question 1. Ozone is an example of __________ molecule.
Answer. Triatomic

Question 2. In water, the ratio of hydrogen and oxygen is __________.
Answer. 2:1

Question 3. The valency of nitrogen in NH3 is __________.
Answer. 3

Question 4. All noble gas molecules are __________ in nature.
Answer. Monoatomic

Question 5. The __________ is the sum of atomic masses of all the atoms present in the molecule.
Answer. Molecular Mass

Question 6. A __________ is a molecule made up of 2 or more different types of atoms.
Answer. Compound

Question 7. The number of atoms needed to make a molecule is called as __________ of that element.
Answer. Atomicity

Question 8. During a chemical reaction matter is neither created nor destroyed, it may change from one form to other, is explained by___________ law.
Answer. Conservation of Mass

Question 9. When there is more number of electrons than protons, the atom is called ________.
Answer. Anion

Question 10. __________ is a tendency in an atom to achieve the state of stability.
Answer. Valency

Question 11. While writing a chemical formula, brackets are required in case of ____________ ions.
Answer. Polyatomic

Question 12. Atoms of the elements are indicated by the ____________ in a chemical formula.
Answer. Symbols

Question 13. 6.022 × 10²³ is the number of atoms in 12 g of ____________.
Answer. Carbon – 12

Question 14. ___________ is the study of the transformation of matter from one form to the other.
Answer. Chemistry

Question 15. Mass of 1 mole of substance is called ____________.
Answer. Molar mass

Question 16. 6.022 × 10²³ is called the ____________.
Answer. Avogadro’s number

Question 17. Law of definite proportion was given by______________.
Answer. Joseph Proust

Question 18. __________ are basic building blocks of matter.
Answer. Atoms

Question 19. The total number of protons present in the nucleus of an atom is called_________.
Answer. Atomic number

Question 20. Electrons present in the outermost orbit are known as_________.
Answer. Valence electrons

Question 21. A positively charged ion is called ________.
Answer. Cation

Question 22. Air conditioners, fluorescent lamps and printers, etc., are generators of __________.
Answer. Ions

Question 23. ___________ refers to the number of atoms present in one molecule of an element or substance.
Answer. Atomicity

Question 24. When a compound contains both metal and non-metal elements the name of ___________ comes first.
Answer. Metal

NEET Foundation Chemistry Notes For Chapter 3 Atoms And Molecules True Or False

Question 1. Law of conservation of mass was given by Antoine Lavoisier and verified by Landolt. (True/False)
Answer. True

Question 2. Protons revolve around the nucleus of an atom (True/ False).
Answer. False

Question 3. The relative mass of molecule is expressed in atomic mass unit (u). (True/False)
Answer. True

NEET Foundation Chemistry Notes For Chapter 3 Atoms And Molecules Match the Column

Question 1. Match the following and choose the correct code:

Select the correct option:

1. A-4, B-3, C-1, D-2
2. A-2, B-3, C-4, D-1
3. A-3, B-1, C-2, D-4
4. A-1, B-4, C-2, D-3

Answer. 3. A-3, B-1, C-2, D-4

Question 2. Match the following and choose the correct code:

Select the correct option:

1. A-4, B-1, C-2, D-3
2. A-3, B-4, C-1, D-2
3. A-2, B-3, C-4, D-1
4. A-4, B-2, C-1, D-3

Answer. 2. A-3, B-4, C-1, D-2

Question 3. Match the following and choose the correct code:

Select the correct option:

1. A-4, B-3, C-1, D-2
2. A-2, B-4, C-1, D-3
3. A-1, B-3, C-2, D-4
4. A-3, B-2, C-4, D-1

Answer. 1. A-4, B-3, C-1, D-2

Question 4. Match the following and choose the correct code:

Select the correct option:

1. A-4, B-3, C-2, D-1
2. A-2, B-1, C-4, D-3
3. A-3, B-2, C-1, D-4
4. A-3, B-4, C-2, D-1

Answer. 4. A-3, B-4, C-2, D-1

Question 5. Match the following and choose the correct code:

Select the correct option:

1. A-3, B-4, C-2, D-1
2. A-2, B-4, C-1, D-3
3. A-1, B-2, C-4, D-3
4. A-4, B-3, C-2, D-1

Answer. 2. A-2, B-4, C-1, D-3

NEET Foundation Chemistry Notes For Chapter 3 Atoms And Molecules Assertion Reasoning

For the following questions the options will remain the following:

1. Both A and R are correct and R is correct explanation of A.
2. Both A and R are correct but R is not a logical explanation of A.
3. A is correct but R is incorrect.
4. R is correct but A is incorrect.

Question 1. Assertion: The molecular mass expressed in grams is called gram molecular mass.
Reason: The molecular mass is equal to the sum of the masses of all the atoms of a molecule.

Answer. 2. Both A and R are correct but R is not a logical explanation of A.

Question 2. Assertion: Ion is a charged chemical particle.
Reason: An ion that carries a positive charge is called a cation and an ion that carries a negative charge is called an anion.

Answer. 1. Both A and R are correct and R is correct explanation of A.

Question 3. Assertion: Molar volume is the volume occupied by various moles of a gas under any conditions of temperature and pressure.
Reason: It is equal to 22.4 liters.

Answer. Both A and R are correct and R is correct explanation of A.

NEET Foundation Chemistry Notes For Chapter 3 Atoms And Molecules Comprehension Passage

An atom is defined as the smallest particle of an element which may or may not be capable of free existence. Atom of hydrogen, oxygen, nitrogen, etc., are highly reactive and do not exist in the Free State. They exist in the combined state with atoms of the same element one atoms of the other elements. Dalton was the first scientist to suggest specific symbols for different elements.

Symbols used by him also represented the quantity of the element, i.e., one atom of the element. The actual masses of the atoms are so small that it is difficult to determine the actual masses of individual atoms. For example, actual mass of an atom of hydrogen is found to be 1.673 × 10^-24 g which is extremely small.

However, it was found convenient to compare the masses of atoms of different element with some reference atom. The masses thus obtained are called relative atomic masses and the scale on which these masses are expressed is called atomic mass scale.

A molecule is the smallest particle of a compound which can exist freely under ordinary conditions and shows all the properties of that substance. Molecules of some elements are very big in size containing a large number of atoms linked together. For example, graphite and diamond contain an infinite number of carbon atoms linked together.

These elements are simply represented by their atomic symbols. A third crystalline form of carbon discovered recently contains 60 C-atoms linked together. It is represented by C₆₀ and is known as Buckminsterfullerene. Molecules of a compound are two or more atoms of different elements combined together in a definite proportion by mass to form a species that can exist freely.

As molecules are made up of two or more atoms of the same or different elements and each atom has a definite atom mass, therefore, molecular mass of a molecule of a substance can be calculated by adding atomic masses of all the atoms present in one molecule of the substance.

Questions:

Question 1. Molecule of a compound means ________.

1. Atoms are held together by a chemical bond.
2. To attract the shared pair of electrons.
3. Different elements combined together in a definite proportion by mass.
4. Compounds are formed by the combination of two or more non-metal atoms.

Answer. 3. Different elements combined together in a definite proportion by mass.

Question 2. Which of the following is true about Dalton’s symbols of elements?

1. Suggested the specific symbols for different elements.
2. Element is the relative mass of its atoms.
3. Substances made up of the same kind of atoms.
4. Atoms of the same element may have different masses.

Answer. 1. Suggested the specific symbols for different elements.

Question 3. Graphite and diamond contains ________.

1. Fixed number of carbon atoms.
2. Infinite number of carbon atoms.
3. Very small number of carbon atoms.
4. No carbon atoms.

Answer. 2. Infinite number of carbon atoms.

Question 4. How the carbon represents through the structure of Buckminsterfullerene?

1. C-12
2. C_a
3. CI
4. C₆₀

Answer. 4. C₆₀

Question 5. What is relative atomic mass?

1. Masses of atoms of different element with some reference atom.
2. Scale of the masses expressed.
3. Average atomic mass of an element.
4. Short method of representing an element.

Answer. 1. Scale of the masses expressed.

Question 6. Law of equivalent proportion was given by:

1. Ritcher
2. Joseph Proust
3. Gay–Lussac
4. Maharshi Kanad

Answer. 1. Ritcher

Question 7. If one walks to a forest, which type of ion he will find more naturally?

1. Negative
2. Positive
3. Both
4. None

Answer. 1. Negative

Question 8. What does the chemical formula of a compound represent?

1. Physical composition
2. Chemical composition
3. Ions
4. Atomic number

Answer. 2. Chemical composition