NEET Biology Class 9 The Fundamental Unit of Life Question And Answers

Chapter 1 The Fundamental Unit Of Life

Cell

Have you ever seen a cell?

Take an onion bulb. Peel off the skin from its inner side using forceps. Then, place individual layers in a watch glass containing water. Carefully transfer each layer on a clean glass slide using a paint brush. Add one-two drops of iodine solution on the material to stain the cell for visualization. Place a cover slip on the material in such a way that no bubbles are formed. Observe the slide under the microscope.

NEET Foundation Class 9 Biology Cell

What do you observe?

You will observe a number of rectangular chambers under the microscope (as shown in the given figure). Each chamber is a cell here. You will find a similar pattern and structure in each slide.

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What are cells? Who named them so?

All living organisms are made up of cells. The Cell is the structural and functional unit of life. It is the smallest living entity found in living organisms.

The term cell was introduced by Robert Hooke in 1665, while examining a slice of cork through his microscope. Cork is obtained from the bark of a tree. Under a compound microscope, he observed many small compartments resembling a honeycomb. He termed these as cells. The given table lists some properties of cells.

NEET Biology Class 9 The Fundamental Unit of Life Question And Answers

WBBSE Class 9 Fundamental Unit of Life Q&A

Properties of cell

  • The Cell is the smallest living unit of life.
  • It is so small that it is not visible to the naked eye.
  • The shape of the cell varies in different organisms and within an organism.
  • Size of cells also differs.
  • All living cells exhibit certain basic properties like respiration, growth, metabolism etc.
  • Cells originate from a pre-existing cell. A mother cell divides to produce daughter cells. Hence, cells exhibit cell division.

Cell is the basic unit of life. All cells vary in their shape, size, and activity they perform. In fact, the shape and size of the cell is related to the specific functions they perform.

The table given below lists the shape and size of certain cells.

NEET Foundation Class 9 Biology Shape and size of certain cells

Amoeba is a simple, unicellular organism. Larger animals are more evolved than unicellular Amoeba. Do you know the reason for this?

Have you ever tried to know how multicellular organisms evolve?

Multicellular organisms have several advantages over unicellular organisms.

  • As division of labour exists in multicellular organisms, a variety of tasks can be performed efficiently. This gives the organism a wide range of adaptability to survive.
  • In multicellular organisms, dead cells play an important role. For example, dead epidermal cells in the skin of animals protect the underlying cells.

Do you know what division of labour is?

Division of labour suggests the specialized functions of organs. All organs, tissues, or cells cannot carry out all the functions. They are evolved to carry out a specific set of functions. Each organ system coordinates with the other to carry out functions required for life. Therefore, by dividing the work or function, they minimize the load of carrying out all functions and therefore, they work or function efficiently.

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Let us learn more about unicellular and multicellular cells.

Organisms are often grouped as unicellular or multicellular organisms. Unicellular organisms represent a single cell, while multicellular organisms are made up of numerous cells.

Some Interesting Facts:

  • The smallest cell in the universe is the Mycoplasma, a type of bacteria. Its diameter is 0.1 µm.
  • The smallest cell in the human body, in terms of volume, is the sperm cell.

The table given below lists the characteristics of some unicellular and multicellular organisms with a few examples.

NEET Foundation Class 9 Biology Characteristics of unicellular and multicellular organisms

Understanding Cell Structure and Function

Cells can also be classified on the basis of their cellular complexity.

Based on their sub-cellular organization and cellular complexity, cells can be classified as prokaryotes and eukaryotes. Animals, plants, fungi, protozoans, and algae, all are composed of eukaryotic type of cells, while bacteria are prokaryotes in nature. Prokaryotes are unicellular organisms, while eukaryotes are usually multicellular organisms. Yeast is exceptionally a unicellular eukaryote. The table given below lists the characteristic features of both prokaryotes and eukaryotes.

NEET Foundation Class 9 Biology Characteristics of prokaryote and eukaryote

Chapter 1 The Fundamental Unit Of Life Worksheet 1

Question 1. Robert Hooke was the first scientist who coined the term ‘cell’. Which cell did he observe under the microscope?

  1. Fiber
  2. Cork
  3. Root
  4. Leaf

Answer. 2. Cork

Question 2. Which of the following organisms is multi-cellular?

  1. Hydra
  2. Amoeba
  3. Paramecium
  4. Dinoflagellate

Answer. 1. Hydra

Question 3. All living organisms are made up of cells. Cells are often referred to as the ‘building blocks’ of life. Which of the following organisms is not a unicellular organism?

  1. Bacteria
  2. Coral
  3. Yeast
  4. Archaea

Answer. 2. Coral

Question 4. Organisms that are made up of many cells are called multi-cellular organisms; whereas organisms that are made up of only a single cell that performs all functions are called unicellular organisms. Which of the following organisms is unicellular?

  1. Pine
  2. Algae
  3. Sundew
  4. Amoebae

Answer. 4. Amoebae

Step-by-Step Guide to Cell Biology Questions

Question 5. Multicellular organisms are made of a large number of cells, wherein each cell performs a specific function. Which of the following organisms is not multicellular?

  1. Plants
  2. Protists
  3. Monkey
  4. Mushrooms

Answer. 2. Protists

Question 6. Which of the following organisms is not multicellular?

  1. Banyan tree
  2. Pea plant
  3. Diatom
  4. Leech

Answer. 3. Diatom

Question 7. An organism made up of a single cell is known as a unicellular organism. Which of the following organisms is not unicellular?

  1. Bacterium
  2. Mushroom
  3. Paramecium
  4. Dinoflagellate

Answer. 2. Mushroom

Question 8. In a multicellular organism, different cells are specialized to perform different functions. Which of the following organisms is multicellular?

  1. Diatom
  2. Bacteria
  3. Euglena
  4. Hydra

Answer. 4. Hydra

Question 9. In a unicellular organism, the single cell performs all the functions necessary for its survival. Which of the following organisms is unicellular?

  1. Pine
  2. Moss
  3. Amoeba
  4. Earthworm

Answer. 3. Amoeba

Question 10. Prokaryotes are distinguished from eukaryotes by the

  1. presence of cell wall
  2. absence of nucleus
  3. presence of ribosomes
  4. absence of chloroplasts

Answer. 2. absence of nucleus

Question 11. Which of the following statements about prokaryotes is true?

  1. All prokaryotes have a cell wall
  2. Nucleus is absent in all prokaryotes
  3. Prokaryotes are larger than eukaryotes
  4. Ribosomes are larger in prokaryotes as compared to eukaryotes

Answer. 2. Nucleus is absent in all prokaryotes

Practice Questions on The Fundamental Unit of Life

Question 12. Which arrow diagram correctly illustrates the arrangement of cell organelles starting from the outermost layer of plant cells?

  1. Plasma membrane  cell wall  cytoplasm  nucleus
  2. Cell wall  plasma membrane  cytoplasm  nucleus
  3. Cell wall  cytoplasm  plasma membrane  nucleus
  4. Plasma membrane  cytoplasm  cell wall  nucleus

Answer. 2. Cell wall  plasma membrane  cytoplasm  nucleus

Question 13. Living organisms are grouped into eukaryotes and prokaryotes on the basis of

  1. ribosomes
  2. nucleus
  3. plasma membrane
  4. chloroplast

Answer. 2. nucleus

Question 14. In multi-cellular organisms, cells are usually

  1. independent of each other
  2. dependent upon each other
  3. incapable of transporting substances
  4. incapable of multiplication

Answer. 2. dependent upon each other

Question 15. Plant cells can perform certain functions which animal cells cannot perform. The function unique to a plant cell is the

  1. exchange of gases
  2. absorption of water
  3. production of starch
  4. transport of nutrients

Answer. 3. production of starch

Question 16. Cells perform the essential life functions in an animal body. Which of the following functions is not performed by animal cells?

  1. Digestion
  2. Respiration
  3. Protein synthesis
  4. Carbohydrate synthesis

Answer. 4. Carbohydrate synthesis

Question 17. As compared to plant cells, animal cells are found in a variety of shapes. Animal cells are found in a verity of shapes because of the presence of a flexible

  1. vacuole
  2. nucleus
  3. cell wall
  4. cell membrane

Answer. 4. cell membrane

Question 18. Vacuole is cell structure present in both plant and animal cells. Which of the following statements about plant and the animal cell vacuoles is true?

  1. The plant cell has many small vacuoles, but the animal cell has one large vacuole.
  2. The plant cell has one large vacuole, but the animal cell has many small vacuoles.
  3. The plant as well as the animal cell has many small vacuoles.
  4. The plant as well as the animal cell has one large vacuole.

Answer. 2. The plant cell has one large vacuole, but the animal cell has many small vacuoles.

Question 19. Which of the following processes does not occur in animal cells?

  1. Photosynthesis
  2. Respiration
  3. Excretion
  4. Osmosis

Answer. 1. Photosynthesis

Question 20. Animal cells are found in a verity of shapes because of the presence of a flexible

  1. Vacuole
  2. Nucleus
  3. Cell wall
  4. Cell membrane

Answer. 4. Cell membrane

Chapter 1 The Fundamental Unit Of Life Cell Wall, Plasma Membrane, And Cytoplasm

We know that a cell contains a cell wall, a plasma membrane, and a cytoplasm.

Can you identify the plasma membrane and the cytoplasm in a cell?

Collect a small piece of onion. Peel off the skin (also called epidermis) from the concave side of the onion using forceps. Place this thin layer of onion skin in a watch glass containing water. Transfer it on a clean glass slide using a paint brush and add a drop of iodine solution to it. Mount a cover slip on the material in such a way that no bubbles are formed inside. Observe it under the microscope.

NEET Foundation Class 9 Biology Cell

What do you observe?

You will observe cells. There is a clear boundary around cells, which is the plasma membrane. A small, dark coloured, round-shaped structure can be seen inside the cell. This is the nucleus of cells. The entire space (apart from the nucleus) is enclosed by the plasma membrane.

The basic component of cells is the protoplasm and plasma membrane. Protoplasm consists of the cytoplasm and the nucleus. Cytoplasm is the cellular matrix in which the nucleus is suspended. However, in bacteria, cellular materials are surrounded by the bacterial cell wall.

In plant cells, the outermost covering also constitutes the cell wall, beneath which the plasma membrane lies.

Let us study the plasma membrane, the cell wall, and the cytoplasm in detail.

The plasma membrane is the outermost covering in animal cells. However, in plant cells and in certain unicellular organisms, the outermost covering is the cell wall. The plasma membrane is a selectively permeable lipid bilayer.

Lipids and proteins are major components of the cell membrane. However, a small amount of carbohydrates can also be found in the plasma membrane. The plasma membrane is flexible in nature.

The table given below lists the various functions of the plasma membrane.

NEET Foundation Class 9 Biology Functions of plasma membrane

Let us explore the process of diffusion and osmosis in detail.

Diffusion

Do you know how nutrients are absorbed in the digestive tract?

In the digestive tract, food is broken down into simpler products such as glucose. Nutrients are then absorbed by the intestinal cells through a process known as diffusion.

Do you know how oxygen reaches the cells in the human body?

The inhaled air contains oxygen. In the lungs, oxygen diffuses through the blood capillaries and reaches the red blood cells. There, it binds with haemoglobin to form oxy-haemoglobin. Oxy-haemoglobin is then circulated throughout the body. In tissues, where oxygen concentration is lesser than blood or the red blood cells, oxygen diffuses out of it and enters into tissues and then into cells.

Osmosis

Osmosis is the movement of water molecules across a semi-permeable membrane from a higher to a lower concentration.

Plasma membrane acts as a semi-permeable membrane. Water moves in and out of cells through osmosis to maintain the amount of water in cells and in the outside environment.

How does water move from one region to another?

Solutions can be of three types: isotonic, hypotonic, and hypertonic. Let us explore the differences between these solutions.

Let us perform an experiment to understand osmosis using raisins or apricots.

Take raisins in three breakers. Pour pure water in the first beaker, isotonic solution in the second, and a high concentrated salt solution in the third beaker.

What do you observe?

After five minutes, you will observe that the raisins swell up in the first beaker. Pure water does not contain salt. Thus, to maintain equilibrium, water enters into the raisins. This swells up the raisins. In the second beaker, you will see no change in the raisins. An isotonic solution contains similar salt concentration as that of raisins. This produces osmotic balance. Hence, no change can be observed. In the third beaker, you will observe that the raisins shrink. This beaker contains a hypertonic solution. To maintain equilibrium, water moves out of the raisins. This shrinks the raisins. Excessive shrinkage results in the breakdown of the membrane. This phenomenon is called plasmolysis.

NEET Foundation Class 9 Biology Hypertonic solution

Artificial kidney dialysis!

An artificial dialysis must be performed when the kidneys stop functioning. Artificial kidney dialysis uses the cellulose membrane, which acts as a semi-permeable membrane. Such a system filters blood through osmosis and diffusion (as the kidneys do). This keeps the body activity normal.

NEET Foundation Class 9 Biology Artificial Kidney dialysis

Differences between osmosis and diffusion Can you distinguish between diffusion and osmosis?

The table given below lists some distinguishing characteristics of diffusion and osmosis.

NEET Foundation Class 9 Biology Characteristics of diffusion and osmosis

Plasma membrane of cells acts as semi-permeable membrane. It allows the movement of water and gaseous molecules freely (diffusion). However, it does not allow the movement of other larger molecules such as sugar, amino acids, etc. All such molecules are transported across the membrane by facilitated diffusion (with the help of other carrier proteins) and active transport (with the expenditure of energy).

Do you know why brine is used to preserve food?

Brine is a high salt concentration solution. Perishable food items such as fish, meat, etc. are preserved for a longer period of time in such solutions. Brine is hypertonic for bacteria. Therefore, water comes out of bacterial cells, causing dehydration. This kills the bacteria. Thus, bacterial contamination is prevented.

Cell wall

The cell wall is the outermost rigid structure in plant cells. The main component providing structural strength to the cell wall is cellulose. However, the bacterial cell wall is mainly composed of peptideglycan. The table given below lists the various functions of the cell wall.

Functions of cell wall:

  • It protects intracellular organelles from the outside environment.
  • It can withstand dilute hypotonic media and prevents bursting of cells. Therefore, plant cells withstand changes in environmental concentration better than animal cells.
  • Plasma membrane establishes communication between cells.

Cytoplasm

The cytoplasm is the inner content of the cell membrane, which is separated from the nucleus. It includes cytosol, organelles, and inclusions. Cytosol is a soft and sticky, semi-transparent fluid in which various cell organelles are suspended. Inclusions are stored nutrients.

The table given below lists various functions of the cytoplasm.

Functions of Cytoplasm:

  • It is the region where many cellular activities take place.
  • It mostly consists of water and it balances the water content in the cell.
  • It contains cytoskeleton, which maintains the shape and movement of cells.
  • Cytoplasmic streaming or circulation of the cytoplasm helps in the proper distribution of cellular organelles during cell division, growth, etc.

Do you know what cybrid is?

Cybrids are cytoplasmic hybrids. Plasma membrane of cells (of different origins) is broken down to obtain cytoplasm. These naked cells are then fused to obtain hybrid cells called cybrids. Cybrids are often known as heterokaryon as they contain the nucleus from different origins. Cybrids are important for research purposes.

Chapter 1 The Fundamental Unit Of Life Worksheet 2

Question 1. Which of the following functions holds true for plasma membrane?

  1. It protects and gives structural support to cells
  2. It contains the genetic material
  3. It regulates substances moving in and out of cells
  4. It maintains the shape of cells

Answer. 3. It regulates substances moving in and out of cells

Question 2. The nucleus of a cell is a membrane-bound organelle that contains the genetic material i.e., DN(A) The cellular material present outside the nucleus is called cytoplasm. Which membrane separates the components of nucleus and cytoplasm?

The Fundamental Unit Of Life Nuclear envelope

  1. Protoplasm
  2. Nucleolus
  3. Plasma membrane
  4. Nuclear envelope

Answer. 4. Nuclear envelope

Question 3. Which organelle forms the outermost layer in animal cells?

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

Answer. 2. Plasma membrane

Question 4. The flow of molecules in and out of a cell is regulated by

  1. cell membrane
  2. mitochondria
  3. golgi body
  4. nucleus

Answer. 1. cell membrane

Question 5. Emily reads about a cell structure made up of proteins and lipids. This structure holds the constituents of the cell together. Which cell structure is described here?

  1. Golgi apparatus
  2. Cell membrane
  3. Cytoplasm
  4. Lysosome

Answer. 2. Cell membrane

Question 6. Osmosis is the movement of molecules from a region of higher concentration to a region of lower concentration. Which of the following processes does not involve osmosis?

  1. Turgidity of living cells
  2. Exchange of gases through stomata
  3. Absorption of water by roots
  4. Opening and closing of stomata

Answer. 2. Exchange of gases through stomata

Question 7. A hypotonic solution is one that contains a low concentration of the solute relative to the comparative solution. A hypertonic solution is one that contains a high concentration of the solute relative to the comparative solution. Isotonic solution is a solution whose solute concentration is equal for both the solutions under comparison. Osmosis occurs when a cell is placed in a solution hypertonic to it. Which of the following observations would be recorded if an animal cell is placed in a solution hypotonic to it?

  1. There would be a drop in the intercellular pressure
  2. There would be a gain in the extra cellular pressure
  3. There would be a movement of contents from the solution to the cell
  4. There would be a movement of contents from the cell to the solution

Answer. 3. There would be a movement of contents from the solution to the cell

Question 8. Cell bursting occurs when cell is immersed in a solution.(x is isotonic to cells) Which alternative completes the given sentence?

  1. The Fundamental Unit Of Life Cell bursting 1
  2. The Fundamental Unit Of Life Cell bursting 2
  3. The Fundamental Unit Of Life Cell bursting 3
  4. The Fundamental Unit Of Life Cell bursting 4

Answer.

3. The Fundamental Unit Of Life Cell bursting 3

Question 9. Human cells are observed to be spherical when placed in an isotonic solution that has 0.9% salt concentration.

The Fundamental Unit Of Life Spherical

What will be the effect of the solution on the cells?

  1. They will shrink in size
  2. They will increase in size
  3. They will burst because of pressure
  4. They will neither increase nor decrease in size

Answer. 4. They will neither increase nor decrease in size

Question 10. A red blood cell is placed in a hypotonic solution. It is observed that

  1. water enters the cell
  2. oxygen enters the cell
  3. water moves out of the cell
  4. oxygen moves out of the cell

Answer. 1. water enters the cell

Question 11. Which of the following biomolecules is not a component of animal cells?

  1. Lipid
  2. Protein
  3. Glucose
  4. Cellulose

Answer. 4. Cellulose

Question 12. A cell structure in the plant cell is made up of cellulose and protects the cell from physical injury. The described cell structure is the

  1. cell wall
  2. chloroplast
  3. mitochondrion
  4. cell membrane

Answer. 1. cell wall

Question 13. In the given figure, label X represents the

The Fundamental Unit Of Life Cell wall

  1. cell membrane
  2. cytoplasm
  3. cell wall
  4. nucleus

Answer. 3. cell wall

Question 14. Cell wall is the outermost covering of the plant cell. Its main function is to

  1. provide support to the cell
  2. provide energy for the cell
  3. take part in lipid synthesis
  4. take part in protein synthesis

Answer. 1. provide support to the cell

Examples of Questions on Cell Organelles

Question 15. The presence of a thick cell wall is one of the important factors that differentiate plant cells from animal cells. The cell wall surrounds the cell or plasma membrane. The presence of cell wall allows plant cells to

 

  1. exhibit mobility
  2. synthesize their own food
  3. separate internal contents of the cell
  4. withstand changes in their surroundings

Answer. 4. withstand changes in their surroundings

Question 16. The given figure shows a labeled plant cell. In the given figure, the cytoplasm is labeled as

The Fundamental Unit Of Life Cell wall 2

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

Answer. 4. 4

Question 17. Cell wall is the most distinguishing feature of plant cells. Which of the following functions is not performed by plant cell wall?

  1. Manufacturing proteins
  2. Giving support to the cell
  3. Providing shape to the cell
  4. Protecting cellular contents

Answer. 4. Protecting cellular contents

Question 18. The cells of which of the following organisms have a cell wall, chloroplast, and a prominent vacuole?

  1. Sea kelp
  2. Sting ray
  3. Star fish
  4. Sea urchin

Answer. 1. Sea kelp

Question 19. Cytoplasm is composed of all cell organelles except nucleus. The contents of nucleus are separated from cytoplasm by the nuclear membrane. Nucleus and nuclear membrane together form nucleoplasm. Cytoplasm and nucleoplasm are together referred to as

  1. protoplast
  2. cytonucleus
  3. protoplasm
  4. nucleolus

Answer. 3. protoplasm

Question 20. Cytoplasm is a water-like substance that is present outside the nucleus and contains all cellular organelles. In animal cells, it occupies nearly half of a cell’s volume. It occupies less space in plant cells. Cytoplasm occupies less space in plant cells because of the

  1. presence of cell wall
  2. presence of vacuoles
  3. absence of cell wall
  4. absence of vacuoles

Answer. 2. presence of vacuoles

Chapter 1 The Fundamental Unit Of Life Nucleus: Structure And Function

We often hear of scientists producing clones.

Do you know what clones are? Do you know how clones are created?

Cloning refers to an identical copy of something. In biology, clones signify genetically identical organisms. The nucleus holds the genetic material. Therefore, if the nucleus is similar in two cells, then they would be similar. Hence, clones are produced by obtaining the nucleus from the cells of donor organisms.

The nucleus, thus obtained, is reintroduced inside the cell whose nucleus is removed. These cells are allowed to grow by providing all the required conditions. Some of these cells divide, producing a zygote. This zygote is then placed inside the uterus of a female recipient to give birth to a baby. Thus, the baby born is identical to the donor organism (whose nucleus is used) and is said to be a clone of the donor.

Have you ever seen a nucleus?

Nucleus is visible under a light microscope. It is acidic in nature. Any basic stain can be used to see the nucleus. Take a toothpick and spool out the materials gently from the inner surface of your cheek. Spread the materials on a clean glass slide and dry it. Add a few drops of methylene-blue solution to the material for staining. After staining, place a cover slip on the material and observe under the microscope.

What do you observe?

You will observe numerous round-shaped cells, which are light blue in colour. Inside each cell, a nucleus can be observed as a dark blue coloured structure.

The nucleus is the largest organelle present in the eukaryotic cells. In mammalian cells, the size of the nucleus typically varies from 11 to 22 µm in diameter. It is spherical in shape.

NEET Foundation Class 9 Biology Structural components and features

How are chromosomes and genetic material present in cells?

Thus, the nucleus controls all life activities. The entire segment of the DNA present is not always functional. The functional regions are calledgenes.

Role of the nucleus in cellular reproduction and heredity

Genetic material is present inside the nucleus. The nucleus plays an important role in cellular reproduction as it divides and passes the genetic material to the offspring. The genetic material decides both the appearance and the function of cells. Therefore, heredity depends upon the division of nucleus.

Chapter 1 The Fundamental Unit Of Life Vacuoles

Do you know what vacuoles are?

Vacuoles are membrane-bound structures, which are believed to store ergastic substances of cells. In plant cells, vacuoles are large in size, while in animal cells vacuoles are small. The table given below lists some functions of vacuoles.

Functions of vacuoles:

  • They help in the removal of unwanted structural debris.
  • They store all the waste products of cells.
  • They maintain the turgor pressure within cells.
  • In Amoeba, food vacuoles store food.

Chapter 1 The Fundamental Unit Of Life Endoplasmic Reticulum

Endoplasmic reticulum, or ER, is an interconnected network of membranous structureslike tubules, vesicles, and cisternae. Cisternae are the flattened disk-like membranous structures. Tubules are tubular in shape, while vesicles are sac-like structures.

There are two types of endoplasmic reticulum, namely smooth endoplasmic reticulum (SER) and rough endoplasmic reticulum (RER). When ribosomes get attached to the surface of smooth endoplasmic reticulum, it becomes rough endoplasmic reticulum.

NEET Foundation Class 9 Biology Endoplasmic reticulum

Functions of smooth endoplasmic reticulum

  • Smooth ER synthesizes fats and lipids.
  • It also takes part in the metabolism of carbohydrates.
  • It actively participates in drug detoxification.
  • It maintains the calcium ion concentration in the cytosol.

Functions of rough endoplasmic reticulum

  • Most of the lysosomal proteins are produced in the rough ER.
  • It transports proteins to various destinations like the plasma membrane.
  • This is the major site of glycosylation (addition of carbohydrates in proteins).

Chapter 1 The Fundamental Unit Of Life Worksheet 3

Question 1. Endoplasmic reticulum forms a tubular network throughout the cell. The main function of the endoplasmic reticulum is to

  1. synthesize glucose in the cell
  2. synthesize lipids in the cell
  3. store water in the cell
  4. store food in the cell

Answer. 2. synthesize lipids in the cell

Question 2. Lysosomes are involved in the autolysis of cells and cell organelles. They also digest themselves when worn out. They disintegrate or fuse with other vacuoles to release lytic enzymes at the site of action. Lysosomes are also known as

  1. power generators
  2. recycling centres
  3. suicidal bags
  4. dictyosomes

Answer. 3. suicidal bags

Question 3. A certain cell organelle controls various activities of the cell such as protein synthesis. It also contains the hereditary information of an organism. The described cell organelle is the

  1. nucleus
  2. ribosome
  3. chloroplast
  4. mitochondrion

Answer. 1. nucleus

Question 4. Which cell organelle does the highlighted region represent?

The Fundamental Unit Of Life Golgi apparatus

  1. Endoplasmic reticulum
  2. Golgi apparatus
  3. Lysosome
  4. Centriole

Answer. 1. Endoplasmic reticulum

Question 5. Nucleus is one of the most important cell organelles in the cell. It performs the function of

  1. controlling the activities of the cell
  2. protecting the cell from physical injury
  3. forming spindle fibers during cell division
  4. removing old cell organelles from the cell

Answer. 1. controlling the activities of the cell

Question 6. The vacuoles present in animal cells are

  1. small, centrally located, and a few in number
  2. large, centrally located, and a few in number
  3. small, scattered, and more in number
  4. large, scattered, and more in number

Answer. 3. small, scattered, and more in number

Question 7. Joshua draws the diagram of a cell organelle. The function of this organelle is to carry out the transport of substances within the cell. Which cell organelle is drawn by Joshua?

  1. Endoplasmic reticulum
  2. Cell membrane
  3. Ribosome
  4. Vacuole

Answer. 1. Endoplasmic reticulum

Question 8. Michael reads about a cell structure in his science book. This structure stores the waste material of the cell. This cell structure is the

  1. vacuole
  2. lysosome
  3. chloroplast
  4. mitochondrion

Answer. 1. vacuole

Question 9. Lysosomes are responsible for the destruction of foreign bodies and dead and worn-out cell organelles. They also digest themselves when worn out.Which of the following substances is present in lysosomes?

  1. Proteins
  2. Fatty acids
  3. Hydrolyses
  4. Nucleic acids

Answer. 3. Hydrolyses

Question 10. Which cell structures are present on the surface of the endoplasmic reticulum as well as scattered throughout the cytoplasm?

  1. Centrioles
  2. Ribosomes
  3. Lysosomes
  4. Mitochondria

Answer. 2. Ribosomes

Conceptual Questions on Applications of Cell Biology

Question 11. The old and worn out cell organelles are removed by the

  1. lysosome
  2. ribosome
  3. nucleus
  4. vacuole

Answer. 1. lysosome

Question 12. A certain cell organelle is surrounded by a single membrane and contains enzymes. This organelle is the

  1. nucleus
  2. lysosome
  3. chloroplast
  4. mitochondria

Answer. 2. lysosome

Question 13. Vacuoles are cell structures present in both plant and animal cells. Vacuoles perform the function of

  1. storing genetic information of the organism
  2. storing water, food, and waste
  3. producing proteins
  4. producing lipids

Answer. 2. storing water, food, and waste

Question 14. The membranous system which helps in the synthesis of fat and proteins and forms vacuoles and vesicles is considered to be the extension of infolded plasmalemma. The given membrane system is known as

  1. endoplasmic reticulum
  2. Golgi apparatus
  3. mitochondria
  4. microtubules

Answer. 1. endoplasmic reticulum

Question 15. The intracellular digestion of macromolecules in a cell is performed by a membranous bag which contains hydrolases. This bag is known as a

  1. chromosome
  2. nucleosome
  3. phagosome
  4. lysosome

Answer. 4. lysosome

Chapter 1 The Fundamental Unit Of Life Golgi apparatus

Golgi apparatus are the membrane-bound, sac-like structures called cisternae. They are arranged parallel to each other in stacks. They were discovered by Camillo Golgi in 1898. Golgi body is usually composed of five-eight cisternae in stacks. Vesicles leave the Golgi body from one end known as the cis face. The other end is known as the trans face. The table given below lists some functions of the Golgi apparatus.

NEET Foundation Class 9 Biology Golgi apparatus 1

Functions of Golgi apparatus:

  • It involves the transport of lipids in cells.
  • It involves the formation of lysosomes.
  • It also takes part in glycosylation and phosphorylation of certain proteins.
  • It plays an important role in the production of proteoglycans. Proteoglycans are the molecules present in the extra cellular matrix of animal cells.

Chapter 1 The Fundamental Unit Of Life Mitochondria And Lysosomes

Mitochondrion is a membrane-enclosed organelle found in eukaryotic cells.

Mitochondria are responsible for the production of most of the energy (or ATP) in cells. Therefore, mitochondria are also known as the power house of cells. A mitochondrion is composed of two lipid membranes, enclosing the matrix. The inner membrane gets folded to form numerouscristae. Cristae are the main site for ATP production. Mitochondrial matrix contains mitochondrial DNA and ribosomes.

NEET Foundation Class 9 Biology mithochondria and lysosomes

Functions of mitochondria:

  • They produce energy required for cells in the form of ATP.
  • They also regulate the free calcium ion concentration in the cytosol.
  • They participate in apoptosis or programmed cell death.

Lysosomes are the membrane-bound vesicles, which contain digestive (hydrolytic) enzymes like acid hydrolase. They digest a variety of substances including worn out organelles, food particles, viruses, and bacteria. They are also known as ‘suicide-bags’ of cells as they burst out and release hydrolytic enzymes in the cytosol, where cells are heavily injured.

Functions of lysosomes:

  • They digest macromolecules by phagocytosis, endocytosis, or autophagy
  • They also take part in auto-cell lysis.

Chapter 1 The Fundamental Unit Of Life Plastids

Do you know what plastids are?

Plastids are major organelles found in plant cells and algae. There are two major types of plastids, namely chromoplasts and leucoplasts.

Chromoplasts are coloured plastids, while leucoplasts are white or colourless plastids. Chromoplasts contain coloured pigments like carotene (orange), xanthophylls (yellow) etc. These pigments are responsible for the colour of plants. Unlike chromoplasts, leucoplasts lack pigments.

Chloroplasts are plastids containing the pigment called chlorophyll. A chloroplast is enclosed by two lipid membranes.

The inner matrix is called the stroma. Thylakoids are the sub-organelles arranged in stacks within the stroma to form grana. The thylakoids are believed to be the main site for photosynthesis. Plastids also contain their own DNA and ribosomes.

NEET Foundation Class 9 Biology Plastids

Functions of plastids:

  • They carry out the process of photosynthesis.
  • They contribute to the colour of leaves, flowers etc.

Chapter 1 The Fundamental Unit Of Life Worksheet 4

Question 1. 

The Fundamental Unit Of Life Cell organelle 1 The Fundamental Unit Of Life Cell organelle 2 The Fundamental Unit Of Life Cell organelle 3 The Fundamental Unit Of Life Cell organelle 4

The cell organelle that is the site for cellular respiration is labeled

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

Answer. 2. 2

Question 2. Which cell organelle does the highlighted region represent?

  1. Plasma membrane
  2. Golgi apparatus
  3. Ribosome
  4. Nucleus

Answer. 2. Golgi apparatus

Question 3. Mitochondria contain their own genetic material for replication. They are also known as semi-autonomous organelles. Which other cell organelle is semi-autonomous?

The Fundamental Unit Of Life Golgi apparatus

  1. Plastids
  2. Ribosomes
  3. Golgi complex
  4. Endoplasmic reticulum

Answer. 1. Plastids

Question 4. Golgi apparatus is made up of stacks of flattened sacs that resemble the endoplasmic reticulum in structure. The main function of the Golgi apparatus is to

  1. package materials for transport outside the cell
  2. produce lipids and proteins in the cell
  3. perform cellular respiration
  4. perform photosynthesis

Answer. 1. package materials for transport outside the cell

Question 5. A certain cell organelle stores and modifies the substances produced by the cell. The change makes the produced substances active. Which cell organelle is described here?

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

Answer. 2. Golgi apparatus

Question 6. Chloroplast is the cell organelle present only in the plant cell. Chloroplast is involved in the production of

  1. glucose
  2. proteins
  3. lipids
  4. water

Answer. 1. glucose

Question 7. Which of the following functions is performed by the mitochondria?

  1. Synthesizes proteins
  2. Cellular respiration
  3. Cellular transport
  4. Stores genes

Answer. 2. Cellular respiration

Question 8. Which of the following structures is not found in animal cells?

  1. Lysosome
  2. Ribosome
  3. Vacuole
  4. Plastid

Answer. 4. Plastid

Question 9. Which of the following statements about mitochondrial respiration is false?

  1. Energy is produced by the mitochondria.
  2. Glucose is utilized by the mitochondria.
  3. CO2 is released by the mitochondria.
  4. O2 is released by the mitochondria.

Answer. 4. O2 is released by the mitochondria.

Question 10. Annie sees a plant which has green leaves as well as leaves with white patches. Annie analyses that photosynthesis is affected in the white patches of the leaves. The white patches appear as a result of the damage to the

  1. mitochondria
  2. chloroplast
  3. ribosome
  4. vacuole

Answer. 2. chloroplast

Question 11. Mitochondria are double membrane bound cell organelles. Mitochondria are involved in the production of

  1. glucose
  2. oxygen
  3. energy
  4. proteins

Answer. 3. energy

Question 12. Semi-autonomous organelles are those which can replicate on their own. These organelles contain the genetic information to carry out protein synthesis required for replication. Which of the following organelles is semi-autonomous?

  1. Ribosomes
  2. Golgi bodies
  3. Mitochondria
  4. Endoplasmic Reticulum

Answer. 3. Mitochondria

Question 13.

The Fundamental Unit Of Life Cell organelle 1 The Fundamental Unit Of Life Cell organelle 2 The Fundamental Unit Of Life Cell organelle 3 The Fundamental Unit Of Life Cell organelle 4

The cell organelle that performs photosynthesis is labeled

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

Answer. 3. 3

Question 14. Chloroplasts perform the function of

  1. osmosis
  2. respiration
  3. transpiration
  4. photosynthesis

Answer. 4. photosynthesis

Key Terms Related to Cell Biology for Class 9

Question 15. Which of the following processes does not occur in animal cells?

  1. Photosynthesis
  2. Respiration
  3. Excretion
  4. Osmosis

Answer. 1. Photosynthesis

Question 16. Which of the following statements about mitochondria is true?

  1. Glucose is prepared by the mitochondria.
  2. Glucose is utilized by the mitochondria.
  3. CO2 is utilized by the mitochondria.
  4. O2 is produced by the mitochondria.

Answer. 2. Glucose is utilized by the mitochondria.

Chapter 1 The Fundamental Unit Of Life Competitive Worksheet

Question 1. The first person to observe a cell under microscope was

  1. M. Schleiden
  2. T. Schwann
  3. Robert Hook
  4. A.V.Leeuwenhoek

Answer. 3. Robert Hook

Question 2. Cell theory was propounded by

  1. Morgan
  2. Halden
  3. Schleiden and Schwann
  4. Robert Hooke

Answer. 3. Schleiden and Schwann

Question 3. The word cell was coined by

  1. Robert hooke
  2. Weismann
  3. Cuvier
  4. Darwin

Answer. 1. Robert hooke

Question 4. Nucleus discovered by

  1. Robert Hooke
  2. Robert Brown
  3. Dujardin
  4. Purkinje

Answer. 2. Robert Brown

Question 5. Smallest cells so far known are

  1. Bacteria
  2. blue green algae
  3. PPLOs
  4. human egg

Answer. 3. PPLOs

Question 6. Which of the following is the longest cell of animal kingdom?

  1. Bacteria
  2. Nerve cell
  3. Virus
  4. Muscle cell

Answer. 2. Nerve cell

Question 7. Which one of the following is an example of prokaryotic cell?

  1. Typical plant cell
  2. Typical animal cell
  3. Bacteria
  4. None of these

Answer. 3. Bacteria

Question 8. What is cytology?

  1. Study of cytoplasm
  2. Study of structure and composition of cell
  3. Study of animal cell only
  4. Study of cell only

Answer. 2. Study of structure and composition of cell

Question 9. Who coined term protoplasm?

  1. Leeuwenhoek
  2. Purkinje
  3. Robert hooke
  4. Robert Brown

Answer. 2. Purkinje

Question 10. Cell is

  1. Functional unit of life
  2. Structural unit of life
  3. Hereditary unit of life
  4. all of the above

Answer. 4. all of the above

Question 11. Plasma membrane is made up of

  1. Proteins and carbohydrates
  2. Proteins and lipids
  3. Proteins and nucleic acids
  4. Proteins, some nucleic acids and lipids

Answer. 2. Proteins and lipids

Question 12. Plant cell wall is mainly composed of

  1. Sugars
  2. Cellulose
  3. Proteins
  4. lipids

Answer. 2. Cellulose

Question 13. Nucleus was discovered of

  1. Robert Brown
  2. Robert Hooke
  3. A.V. Leeuwenhoek
  4. Schwann

Answer. 1. Robert Brown

Question 14. A solution is said to be hypotonic when

  1. Concentration of medium is higher than that of the cell
  2. Concentration of medium is equal to that of the cell
  3. Concentration of medium is lower than that of the cell
  4. None of the above are correct.

Answer. 3. Concentration of medium is lower than that of the cell

Question 15. Cell wall shows

  1. Complete permeability
  2. semipermeability
  3. Differential permeability
  4. impermeability

Answer. 1. Complete permeability

Question 16. Plasma membrane is

  1. Impermeable
  2. formed of cellulose
  3. selectively permeable
  4. nonselective

Answer. 3. selectively permeable

Question 17. Ribosome was named by

  1. Palade
  2. Porter
  3. de Duve
  4. Koliker

Answer. 1. Palade

Question 18. Ribosome consist of

  1. DNA and protein
  2. RNA and protein
  3. RNA and amino acids
  4. RNA and DNA

Answer. 2. RNA and protein

Question 19. The solution having concentration equal to the concentration of solution of inside the cell is called as

  1. Isotonic solution
  2. hypotonic solution
  3. Hypertonic solution
  4. all of the above

Answer. 1. Isotonic solution

Question 20. If a cell will be placed in hypotonic solution what will happen to it ?

  1. The cell will swell and burst
  2. The cell will become flaccid
  3. It will remain unchanged
  4. None of the above

Answer. 1. The cell will swell and burst

Question 21. What is more abundant in smooth endoplasmic reticulum?

  1. Cistemae and vesicle
  2. Tubules
  3. Tubules and vesicles
  4. Cistemae

Answer. 2. Cistemae and vesicle

Question 22. Mitochondria are concerned with

  1. Kreb cycle
  2. C, cycle
  3. glycolysis
  4. none of the above

Answer. 1. Kreb cycle

Question 23. Which of the following organelle is the site of Kreb cycle?

  1. Ribosome’s
  2. Lysosomes
  3. eukaryotic cells
  4. Nucleus

Answer. 3. eukaryotic cells

Question 24. Mitochondria are absent in

  1. Prokaryotic cells
  2. RBC of mammals
  3. eukaryotic cells
  4. (A) and (B) Both

Answer. 4. (1) and (2) Both

Question 25. Mitochondria stores energy in from of

  1. Heat energy
  2. ATP
  3. light energy
  4. none of the above

Answer. 2. ATP

Question 26. The ATP synthesizing units of Mitochondria are

  1. Oxysomes
  2. peroxysomes
  3. glyoxysomes
  4. lysosomes

Answer. 1. Oxysomes

Question 27. Lipid synthesis is performed by

  1. Rough ER
  2. smooth ER
  3. both of above
  4. none of the above

Answer. 3. both of above

Question 28. Who observed Mitochondria at first?

  1. Porter
  2. Palade
  3. Koliker
  4. Camilo Golgi

Answer. 3. Koliker

Question 29. Detoxification of body is done by?

  1. Mitochondria
  2. lysosomes
  3. Smooth endoplasmic reticulum
  4. rough endoplasmic reticulum

Answer. 3. Smooth endoplasmic reticulum

Question 30. Golgi apparatus is made of

  1. Cisternae
  2. vesicles
  3. golgian vacuoles
  4. all of the above

Answer. 4. all of the above

Question 31. Which of the following is called as ‘Suicidal bags’ ?

  1. Centrosome
  2. Lysosome
  3. Microsome
  4. Mesosomes

Answer. 2. Lysosome

Question 32. Eukaryotic ribosomes are

  1. 30s
  2. 50s
  3. 80s
  4. 70s

Answer. 3. 80s

Question 33. Plastids that are white in colour (Pigment free)

  1. chloroplast
  2. lysosome
  3. leucoplast
  4. Chromoplast

Answer. 3. leucoplast

Question 34. Striking difference between a plant cell and an animal cell is due to the presence

  1. mitochondria
  2. plasma membrane
  3. cell wall
  4. ribosome

Answer. 3. cell wall

Question 35. Tonoplast is the membrane surrounding the

  1. cytoplasm
  2. vacuole
  3. nucleus
  4. mitochondria

Answer. 2. vacuole

Question 36. Lysosomes are responsible for

  1. protein synthesis
  2. digestion of organic molecules
  3. fat synthesis
  4. fat emulsification

Answer. 2. digestion of organic molecules

Question 37. In prokaryotic cell

  1. nucleus is developed
  2. membrane bounded organelles are present
  3. double membrane bounded organelles are absent
  4. none of these

Answer. 3. double membrane bounded organelles are absent

Question 38. A typical plant cell contains

  1. cell well
  2. plastids
  3. large vacuole
  4. all of the above

Answer. 4. all of the above

Question 39. The waste disposal system of cell is formed by

  1. lysosomes
  2. peroxysomes
  3. mitochondria
  4. glyoxysomes

Answer. 1. lysosomes

Question 40. In which cell Centriole is absent?

  1. plant cell
  2. Animal cell
  3. Both of above
  4. None of above

Answer. 1. plant cell

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