WBBSE Solutions For Class 8 School Science Chapter 6 The Structure of Living Organisms Short Answer Type Questions

Chapter 6 The Structure Of Living Organisms Short Answer Type Questions

Question 1. What is a microscope?
Answer:

Microscope:

Microscopes are instruments which can both magnify and resolve small objects so that they can be used for observing objects which are not visible to the naked eye. The magnification may range from 15 to 20 times (simple microscope) to 107 times (Electron microscope).

Question 2. What is meant by the magnification of a microscope?
Answer:

Magnification of a microscope:-

Magnification is the power of enlargement or ratio of the size of an object observed under the microscope and its actual size seen with the unaided naked eye.

Question 3. What is meant by resolving the power of a microscope?
Answer:

Resolving the power of a microscope:

The ability to distinguish two close points as distinct clear points are called the resolving power or limit of resolution of a microscope.

WBBSE Class 8 Structure of Living Organisms Short Answer Solutions

Question 4. Write the functions of the cell membrane. Important functions are—
Answer:

Functions of the cell membrane:

1. Help in cellular compartmentalization.
2. Bind the semifluid contents of the cell.
3. Protect the cell from injury.
4. Act as a semipermeable membrane between a cell and its environment.

Question 5. Write the functions of mitochondria. Important functions are—
Answer:

Functions of mitochondria:

1. Act as a powerhouse of a cell by forming ATP.
2. Contain several enzymes.
3. Transmit some genetic information from one generation to other.

Read And Learn More WBBSE Solutions For Class 8 School Science Short Answer Type Questions

Question 6. Name the different types of plastids and state their specific roles in the plant body.
Answer:

Three types of plastids and their roles are—

1. Chloroplastid—helps photosynthesis.
2. Chromoplastid—Produce the colour of the flower.
3. Leucoplastid—Store food materials.

Question 7. Write the common function of RER and SER.
Answer:

Common function of RER and SER:

1. Provide a large surface area inside a cell for performing biochemical reactions.
2. Act as a cytoskeletal framework.

Question 8. What is autolysis? State the cell organelle associated with it.
Answer:

Autolysis:

Autolysis is the self-destruction of a cell, tissue or organ with the help of lysosomes. It occurs in ageing, dead and diseased cells.

Question 9. What are vacuoles? How they are formed?
Answer:

Vacuoles:

Vacuoles are non-cytoplasmic areas present inside the cytoplasm. They are believed to be formed by expansion and pinching off from the endoplasmic reticulum.

Chapter 6 Living Organisms Short Answer Questions WBBSE

Question 10. What are cell inclusions or orgastic substances?
Answer:

Cell Inclusions or Orgastic substances:

These are non-living substances present in the cell. They may be organic or inorganic and may be present inside cell in soluble or insoluble states. Cell inclusions are generally of three categories—reserve food, excretory or secretory products and mineral matters.

Question 11. What are the principal types of cells?
Answer:

Principal types of cells:-

Cells are generally of two types—prokaryotic cells (ex-bacteria) and eukaryotic cells (plant and animal cells with true nuclei).

Question 12. Name the double-membraned and membrane-less cell organelles.
Answer:

Double membrane—Mitochondria and chloroplast. Membrane less—Ribosome and centrosome.

Question 13. What is a unit membrane?
Answer:

Unit membrane:

All cellular membranes (like plasma membrane, mitochondrial membrane, Golgi membrane, etc.), are similar in structure and hence it is called unit membrane. It is composed of protein and lipids.

Question 14. What is nuclear reticulum?
Answer:

Nuclear reticulum:

These are network-like structures found inside the nucleus of non-dividing cells. They are formed of DNA and protein. These structures condense during cell division and form chromosomes.

WBBSE Class 8 Science Short Answer Format

Question 15. What are the characteristics of mammalian RBCs?
Answer:

Characteristics of mammalian RBCs

Mammalian RBCs are biconcave disc-like cells. They lack a nucleus and hence can hold more haemoglobin. This helps in carrying more oxygen to cope with higher metabolic activities.

Question 16. What are the advantages of multicellular organisms?
Answer:

Advantages of multicellular organisms:

1. Different cell types help in the division of labour.
2. Cells can adjust properly to the changing environment and can perform specialized functions.

Question 17. Write the characteristics of eukaryotic cells.
Answer:

Characteristics of eukaryotic cells:

1. The cells have a definite nucleus.
2. Definite chromosomes are present.

Membrane-bound cell organelles like— Mitochondria, Golgi bodies, etc., are found.

Question 18. Write the similarities between animal and plant cells.
Answer:

Similarities between animal and plant cells:

Both types of cells possess—

1. nuclear membrane,
2. true nucleus and
3. membrane-bound cell organelles like- mitochondria, endoplasmic reticulum etc.

Question 19. What is a tissue?
Answer:

Tissue:

A group of cells of similar origin and function constitute a tissue. Every organ consists of many tissues. For example—our stomach contains epithelial, muscular, nervous and connective tissues.

Short Answer Questions for Structure of Living Organisms

Question 20. What is primordial utricle ?
Answer:

Primordial utricle:

In plant cells, due to the presence of a large vacuole, the nucleus and cytoplasm are pushed towards the periphery of the cell forming a thin layer beneath the cell membrane. This layer is known as a primordial utricle.

 

 

Question 21. Write the differences between a Light microscope and an Electron microscope.
Answer:

Differences between a Light microscope and an Electron microscope:

Points of differences	Light microscope	Electron microscope
1. Illumination	Visible light.	A beam of electrons.
2. Lenses	Glass lenses.	Electron lens
3. Electricity	Not required.	Required.
4. Contrast	Achieved by dyes.	Archived by use of heavy metals.
5. Size	Small and portable.	Large and fixed.
6. Magnification	2000-4000X.	50,000-3,00,000X.

 

Question 22. Write the differences between Unicellular and Multicellular organisms.
Answer:

Differences between Unicellular and Multicellular organisms:

Points of differences	Unicellular	Multicellular
1. Number of cells	Single.	Large number.
2. Function	The same cell performs all functions. Not found.	Different cells perform different functions.
3. Division of labour	Not found.	Well observed
4. Size	Microscopic	Generally macroscopic.

 

Living Organisms Chapter 6 Study Guide WBBSE

Question 23. What is protoplasm? What is middle lamella?
Answer:

Protoplasm:

Protoplasm is the physical basis of life within which occurs all the vital functions of life. It is a viscous substance present inside the cell membrane of all living cells. It consists of cytoplasm, nucleus and vacuoles.

In multicellular plants, cells do not move as they are firmly joined together. The common cementing layer present between two adjacent cells is called the middle lamella.

 

 

Question 24. Write the differences between Mitochondria and Chloroplast.
Answer:

Differences between Mitochondria and Chloroplast:

Points of differences	Mitochondria	Chloroplast
1. Colour	Colourless.	Generally green.
2. Occuranee	All eukaryotic cells.	Only in plant cells.
3. inner membrane.	Become folded to form cristae.	Unfolded and remain attached to thylakoids.
4. Energy source	Convert chemical energy.	Convert light energy.

 

Question 25. Write differences among Chloroplastid, Chromoplastid and Leucoplastid.
Answer:

Differences among Chloroplastid, Chromoplastid and Leucoplastid:

Chloroplastid	Chromoplastid	Leucoplastid
1. Green in colour.	Coloured, other than green.	Colourless.
2. Green chlorophyll pigment present.	Non-chlorophyll pigment is present.	Pigments absent.
3. Found in leaves and stem	Found in flowers, fruits etc.	Found in the root.
4. Help in photosynthesis.	Help in pollination and dispersal of seeds.	Help in food storage.

 

Question Who discovered the nucleus? Draw a typical nucleus showing its structures.
Answer:

Robert Brown first discovered the nucleus.

 

Short Answer Resources for Class 8 Structure of Living Organisms

Question 26. Write the differences between the Cell membrane and the Cell wall.
Answer:

Differences between the Cell membrane and the Cell wall:

Points of differences	Cell membrane	Cell wall
1. Location	Both animal and plant cells.	Only in plant cells.
2. Composition	Protein and lipid.	Cellulose, hemicellulose, lignin, etc.
3. Nature	Thin, elastic, living and semipermeable.	Thin, non-elastic, dead and permeable.

 

Question 28. Write the differences between Nucleoid and Nucleus.
Answer:

Differences between Nucleoid and Nucleus:

Points of differences	Nucleoid	Nucleus
1. Covering membrane	Absent.	Present.
2. Component absent	Nucleolus absent.	Nucleolus present.
3. Chromosome	Absent.	Present.
4. Location	Prokaryotic cell.	Eukaryotic cell.

 

Question 29. Name the organelles which are described by the following-

1. transporting channel of the cell
2. A powerhouse of the cell
3. Digestive bag of cell
4. Control room of the cell

What is a prokaryotic cell?
Answer:

1. ER
2. mitochondria
3. Lysosome
4. nucleus

A cell having intermediate characters of prokaryotes and eukaryotes is called a eukaryotic cell. Ex: Marine photosynthetic dinoflagellates

Question 30. Write the differences between Mesosomes and Mitochondria.
Answer:

Differences between Mesosomes and Mitochondria:

Points of differences	Mesosome	Mitochondria
1. Location	Prokaryotic cell.	Eukaryotic cell.
2. Origin/Formation	From the folding of the cell membrane.	From pre-existing mitochondria.
3. Membrane	Single membrane-bound	Double membrane-bound.
4. Cristae	Absent.	Present.

 

Question 31. Write the Difference between Nucleoplasm and Cytoplasm
Answer:

Difference between Nucleoplasm and Cytoplasm:

Points of differences	Cytoplasm	Nucleoplasm
1. Location	In between the cell membrane and nuclear membrane.	Inside the nuclear membrane.
2. Function	Hold cell organelles.	Hold nucleolus and nuclear reticulum.
3. Division	Divisible into ectoplasm and endoplasm.	No such division.

 

Question 32. Meristematic cells have a prominent nucleus and dense cytoplasm but they lack vacuole-why? What happens when

1. The plasma membrane of a cell breaks down
2. Golgi apparatus is removed from a cell?

Answer:

Meristematic cells lack vacuoles to regulate cell division continuously.

1. The cell will die
2. Lysosomes will not be formed.

Question 33. Write the differences between Golgi bodies and the Endoplasmic reticulum.
Answer:

Differences between Golgi bodies and the Endoplasmic reticulum:

Points of differences	Golgi bodies	Endoplasmic reticulum
1. Location	Close to the nucleus.	Scattered throughout the cytoplasm.
2. Types	Only one type.	Two types-rough and smooth.
3. Function	Secretion.	Protein and lipid synthesis. Also, form a cellular skeletal framework.

 

WBBSE Class 8 Science Practice Questions on Living Organisms

Question 34. Write the differences between the Endoplasmic reticulum and the Nuclear reticulum.
Answer:

Differences between the Endoplasmic reticulum and the Nuclear reticulum:

Points of differences	Endoplasmic reticulum	Nuclear reticulum
1. Nature	Cell organelle.	Part of the nucleus.
2. Structure	Tubular.	Network like.
3. Composition	Membrane-bound.	Made up of DNA and protein.
4. Function	Form cellular framework.	Carry hereditary material.

 

Question 35. Write the differences between the Rough endoplasmic reticulum and Smooth endoplasmic reticulum.
Answer:

Differences between the Rough endoplasmic reticulum and Smooth endoplasmic reticulum

Points of differences	Rough ER	Smooth ER
1. Structure	Rough.	Smooth.
2. Ribosomal association	Ribosomes associated.	Ribosomes are not associated.
3. Function	Help in protein synthesis.	Help in the synthesis and storage of lipids.

 

WBBSE Class 8 Science Important Short Answers

Question 36. Write briefly about the structure of the centrosome. Mention its functions.
Answer:

Structure of the centrosome:

Centrosome consists of two parts: centrioles and centrosphere. Centrioles appear as two empty cylinders during cell division. They are situated at right angles to each other. Each cylinder is made up of fine microtubules arranged longitudinally.
The centrosphere is the clear homogeneous cytoplasm present around the centrioles. Functions:

1. Centrioles are necessary for spindle formation during cell division
2. The tail of spermatozoa is formed from one centriole.

 

 

Question 37. Write the differences between nuclei and Nucleolus.
Answer:

Differences between nuclei and Nucleolus:

Points of differences	Nucleus	Nucleolus
1. Location	Important cell organelle, present within the cytoplasm.	Part of the nucleus is present in the nucleoplasm.
2. Membrane association	Membrane-bound structure.	Not bound by a membrane.
3. Function	Control cellular activities and lodge genetic information.	Help in the synthesis of ribosomal RNA.

 

Question 38. Some of the adaptations in animals are given below:

1. White fur
2. Strong tail
3. a layer of fat under the skin
4. thick skin
5. Long beak.

Which of these adaptations are for polar regions? What do you mean by xerophytes?
Name the cells located in gills which can expel excess Na+ and Cl “from the body.
Answer:

Adaptations marked (1), (3) and (4). Plants growing in deserts or situations with a great dearth of water are called Xerophytes Example: Cactus Chloride cells (in gills).