Students can practice the best Class 9 Science MCQ and Class 9 Science Exploration Chapter 2 MCQ Online Test with Answers Cell The Building Block of Life for exam preparation.
Class 9 Science Chapter 2 Cell The Building Block of Life MCQ
Cell The Building Block of Life MCQ
Class 9 Science Chapter 2 MCQ Online Test
Question 1.
Who was the first person to observe a cell using a microscope?
A. Anton van Leeuwenhoek
B. Robert Ilooke
C. Matthias Schielden
D. Rudolf Virchow
Solution:
(B) In 1665. Robert Hooke used a self-designed microscope (200 – 300 X) to observe a thin slice of cork and named the compartments cells’.
Question 2.
Choose the incorrect statement from the following options. (Competency-Based Question)
A. All cells arise from pre-existing cells only
B. Rudolf Virchow proposed the cell theory
C. Nucleus was discovered by Robert Brown in 1831
D. Cell wall provides structural rigidity to the cell
Solution:
(B) The cell theory was proposed by Schleiden (1838) and Schwann (1839).
Question 3.
The limit of resolution of the human eye is
A. 1mm
B. 0.1mm
C. 0.01 mm
D. 10mm
Sol.
(B) When viewed from about 25 cm (near point of the human eye), two points separated by 0.1 mm can be seen as distinct. This is the limit of resolution.
Question 4.
Two cells, A and B, are placed in a solution. Cell A allows only water and small molecules to enter, while Cell B allows almost all molecules. Which cell has a plasma membrane closer to normal function?
A. Cell A
B. Cell B
C. Both A and B
D. Neither A nor B
Solution:
(A) Cell A has a plasma membrane closer to normal function. A normal plasma membrane is selectively permeable, meaning it allows only certain substances like water and small molecules to pass through while restricting others. Cell A shows this property, whereas Cell B allows almost all molecules, which is not typical of a normal cell membrane.
Question 5.
Select the odd one out.
A. The movement of water across a semi-permeable membrane is affected by the amount of substances dissolved in it
B. Membrane are made up of organic molecules like proteins and lipids
C. Molecules soluble in organic solvents can easily pass through the membrane
D. Plasma membrane contain chitin sugar in plants
Solution:
(D) Plasma membrane is a selectively permeable membrane that is made up of a lipid bilayer and proteins. It is present inside the cell wall in plant cells. Chitin is present in the cell wall of fungi and algae.
Question 6.
The table lists some functions performed by some cell structures.
P. It separates the content of the cell from the surroundings.
Q. It is a site where many cellular processes occur.
R. It control the process of cell division.
S. It controls the movement of substances in and out of the cells.
Which option shows the organelle correctly matched with the respective function?
A. Cytoplasm -Q and S, nucleus – P, plasma membrane – R
B. Cytoplasm -Q and R, nucleus – P, plasma membrane – R
C. Cytoplasm -Q, nucleus -R, plasma membrane – S and P
D. Cytoplasm R, nucleus – Q, plasma membrane – A and R
Solution:
(C) The plasma membrane separates the cell’s contents from its surroundings and controls the movement of substances in and out. The cytoplasm is where many cellular processes occur, and the nucleus controls cell division and other genetic functions.
Question 7.
The thickness of the cell membrane is approximately
A. 7 to 10 nm
B. 70 to 100 nm
C. 1 to 5 nm
D. 100 to 200nm
Solution:
A. 7 to 10 nm
Question 8.
Following are a few definitions of osmosis. Read carefully and select the correct definition. (NCERT Exemplar)
A. Movement of water molecules from a region of higher concentration to a region of lower concentration through a semipermeable membrane
B. Movement of solvent molecules from its higher concentration to lower concentration
C. Movement of solvent molecules from higher concentration to lower concentration of solution through a permeable membrane
D. Movement of solute molecules from lower concentration to higher concentration of solution through a semi-permeable membrane
Solution:
(A) The correct defInition of osmosis is the movement of water molecules from a region of higher concentration to a region of lower concentration through a semi-permeable membrane.
Question 9.
If a red blood cell is placed in distilled water, what will happen? (NCERT Exemplar)
A. It will shrink
B. It will swell and may burst
C. It will remain unchanged
D It will undergo plasmolysis
Solution:
(B) It will swell and may burst as distilled water is hypotonic, so water enters the RBC by osmosis, causing it to swell and possibly burst (haemolysis).
Question 10.
A cell will swell up if the
A. concentration of water molecules in the cell is higher than the concentration of water molecules in the surrounding medium
B. concentration of water molecules in surrounding medium is higher than the concentration of water molecules in the cell
C. concentration of water molecules is same in the cell and in the surrounding medium
D. concentration of water molecules does not matter
Solution:
(B) Osmosis is a spontaneous process where movement of water molecules occurs from a region of its higher concentration to a region of lower concentration through a selectively permeable membrane.
When movement of the solvent takes place from outside to inside of the cell (inward movement), the process is called endosmosis. It occurs in hypotonic solution and causes swelling of the cell.
Question 11.
A student observes a prokaryotic cell. Which feature confirms it is prokaryotic?
A. Presence of a nucleoid region instead of a true nucleus
B. Membrane-bound organelles
C. Presence of DNA
D. Large central vacuole
Solution:
(A) Presence of a nucleoid region instead of a true nucleus confirms the cell is prokaryotic because prokaryotes lack a membrane-bound nucleus; instead, their DNA is present in a nucleoid.
Question 12.
In which cells did Camillo Golgi first observe the Golgi apparatus?
A. Onion root cells
B. Nerve cells
C. Human RBCs
D. Pancreatic cells
Solution:
B. Nerve cells
Question 13.
The table below describes some of the organelles visible in a cell under a microscope. Identify the type of living organism to which the cell belongs.
| Cell Organelles | Descriptions |
| Cell wall | Present |
| Vacuole | Large |
| Centriole | Not visible |
| Nucleus | Present |
A. It is the cell of an animal
B. It is the cell of a plant
C. It is the cell of a bacterium
D. It is the cell of a virus
Solution:
(B) From the information given in the table above, we can say that the type of living organism to which this cell belongs is plant because a plant cell bears a cell wall and a large central vacuole. Also, the centrioles are not visible.
Question 14.
Choose the group of cell parts that are not found in prokaryotic cells.
A. Ribosomes, nucleus, mitochondria
B. Ribosomes, cell membrane, cytoplasm
C. Nucleus, mitochondria, chloroplasts
D. Cell wall, ribosomes, cytoplasm
Solution:
(C) Prokaryotic cells do not have membrane-bound organelles like the nucleus, mitochondria, or chloroplasts. They only have simple structures like ribosomes, cell membrane, and cytoplasm.
Question 15.
Which of these options are not a function of ribosomes? (NCERT Exemplar)
I. It helps in manufacture of protein molecules.
II. It helps in manufacture of enzymes.
III. It helps in manufacture of hormones.
IV. It helps in manufacture of starch molecules.
A. I and II
B. II and III
C. III and IV
D. IV and I
Solution:
(C) Ribosomes play important role in synthesis of proteins. All enzymes are proteins, but all hormones are not proteins. Therefore, ribosomes synthesise only proteins and enzymes and not hormones and starch.
Question 16.
Which one of the following cellular functions is performed by the endoplasmic reticulum? (CBSE Question Bank)
A. Production of hydrolytic enzymes
B. Supply of energy to cell
C. Formation of lysosomes
D. Production of vacuoles
Solution:
(A) Rough Endoplasmic Reticulum (RER) helps in the production of the digestive or hydrolytic enzymes (proteins).
Question 17.
The proteins and lipids, essential for the building of the cell membrane, are manufactured by
A. rough endoplasmic reticulum and smooth endoplasmic reticulum
B. Golgi apparatus
C. plasma membrane
D. mitochondria
Solution:
(A) The proteins and lipids, essential for the building of the cell membrane, are manufactured by rough endoplasmic reticulum and smooth endoplasmic reticulum, respectively. This process is known as membrane biogenesis.
Question 18.
Which cell organelle plays a crucial role in detoxifying many poisons and drugs in a cell? (NCERT Exemplar)
A. Golgi apparatus
B. Lysosomes
C. Smooth endoplasmic reticulum
D. Vacuoles
Solution:
(C) Smooth endoplasmic reticulum plays a crucial role in detoxifying many poisons and drugs in a cell.
Question 19.
Which of the following is a correct combination of cell organelle and its function?
A. Nucleus – Controls cell activities
B. Mitochondria – Stores genetic material
C. Ribosome – Transports materials inside the cell
D. Cell membrane – Produces energy for the cell
Solution:
(A) The nucleus acts as the control centre of the cell, regulating all its activities. Other parts, like mitochondria, produce energy. Ribosomes make proteins, and the cell membrane controls what enters and leaves the cell.
Question 20.
Which organelle would be more abundant in a cell actively secreting enzymes?
A. Mitochondria
B. Golgi apparatus
C. Lysosomes
D. Vacuole
Solution:
(B) Cells that secrete enzymes have an extensive Golgi apparatus to package and transport the enzymes.
Question 21.
Organelle other than nucleus, containing DNA is (NCERT Exemplar)
A. endoplasmic reticulum
B. Golgi apparatus
C. mitochondria
D. lysosome
Solution:
(C) Organelles other than nucleus containing DNA is mitochondria. It contains its own DNA and ribosomes; hence, is able to make some of its own proteins.
Question 22.
Refer to the given Venn diagram. (Competency-Based Question)
Select the correct option regarding organelle A.
A. Organelle A could be the smallest organelle, which is absent in mature mammalian RBCs
B. Organdile A has outer membrane infolded into finger-like processes called cristae, which bear oxysomes
C. Organelle A is a semi-autonomous organelle, often referred to as kitchen of cells
D. All of the above
Solution:
(C) Chloroplasts are called semi-autonomous organelle and contains green colour pigment called chlorophyll, which helps the cell to prepare their own food by the process of photosynthesis. This is is why chloroplast is known as the kitchen of the cell. Also, chloroplast is enclosed by a double membrane.
Question 23.
Among the listed organelles, identify the one encapsulated by a single layer rather than a double-layer membrane.
A. The cellular ‘powerhouse’ generating AT?.
B. The fluid-filled reservoir that maintains turgidity.
C. The organelle enclosing chromatin and the nucleolus
D. The photosynthetic compartment harboring chlorophyll pigments
Solution:
(B) The fluid-filled reservoir that maintains turgidity is vacuole. It is a single-layered (monolayered) organelle, rest all the organelles mentioned in option (A) (mitochondria), (C) (nucleus), and (D) (chloroplast) are double-membrane (bilayered) bound organelles.
Question 24.
Which out of the following is not a function of vacuole? (NCERT Exemplar)
A. Storage
B. Providing turgidity and rigidity to the cell
C. Vaste excretion
D. Locomotion
Solution:
(D) Vacuoles are the storage sacs which provide turgidity and rigidity to the cell and help in waste excretion. They do not play any role in locomotion.
Question 25.
Select the incorrect statement regarding mitosis. (Competency-Based Question)
A. It helps in growth and repairing of tissues
B. It helps to replace old, dead, and injured cells
C. The mother cell forms two identical daughter cells
D. It occurs in two stages
Solution:
(D) The incorrect statement regarding mitosis is that it occurs in two stages. Mitosis is a single-stage division, while meiotic cell division occurs in two stages, i.e., meiosis-I and meiosis-II.
Question 26.
Choose the location in plant where the meiotic cell division takes place.
A. Leaves and stem
B. Stem and branches
C. In anther and ovary
D. None of these
Solution:
(C) The meiotic cell division occurs in anthers and ovary to form pollen grain (male gamete) and egg cell (female gamete).
Question 27.
Cancer cells divide uncontrollably because they lose
A. their nucleus
B. contact inhibition
C. their cell membrane
D. mitochondna
Solution:
(B) Normal animal cells stop dividing when they touch neighbouring cells (contact inhibition). Cancer cells lose this control, divide uncontrollably, and form tumours.
Question 28.
Which of the following best describes a malignant tumour?
A. It grows slowly and remains confined to one place
B. It spreads rapidly to other parts of the body
C. It does not involve any mutation
D. It helps in normal body growth
Solution:
(B) It spreads rapidly to other parts of the body.
Question 29.
Arun Kumar Sharma is known for his work on
A. mitochondria
B. chromosomes in plants
C. lysosomes
D. cell membranes
Solution:
B. chromosomes in plants
Question 30.
Which of the following statement is correct about history of cell?
A. Rudolf Virchow discovered ccli first time
B. Robert Brown discovered living cell
C. Leeuwenhoek first discovered living cell in pond water
D. Schleiden discovered protoplasm.
Solution:
C. Leeuwenhoek first discovered living cell in pond water.
Antonie van Leeuwenhoek was the first to observe living cells (microorganisms) in pond water using his simple microscope. Robert Hooke only observed cell walls in cork, which were non-living.
Question 31.
Select the group in which all organisms have cells that lack a nucleus
A. bacteria, Amoeba, fungi. plants, animais
B. bacteria, blue-green algae, archaea, fungi, plants
C. bacteria, blue-green algae, archaea
D. Amoeba, Paramecium, bacteria, fungi, plants
Solution:
C. bacteria, blue-green algae, archaea.
All these organisms are prokaryotes, meaning their cells lack a true nucleus. Other groups, like fungi, plants, and animals, are eukaryotes and have a well-defined nucleus.
Question 32.
In the absence of endoplasmic reticulum, which of the following options does not occur in the cell? (Competency-Based Question)
A. Membrane biosynthesis
B. ATP generation
C. Packaging of materials
D. Photosynthesis
Solution:
A. Membrane biosynthesis
The endoplasmic reticulum is responsible for the synthesis of cell membranes and membrane-bound proteins. Without ER, the cell cannot produce new membranes efficiently, though ATP generation and photosynthesis continue normally.
Question 33.
The given below cell organelle involved in forming complex sugars from simple sugars are
A. endoplasmic reticulum
B. ribosomes
C. plastids
D. Golgi apparatus
Solution:
D. Golgi apparatus
(D) The Golgi apparatus modifies and converts simple sugars into complex sugars and other macromolecules. Other organelles like ribosomes, ER, and plastids have different functions such as protein synthesis, lipid synthesis, and photosynthesis/storage.
Question 34.
Programmed Cell Death (PCD) during embryo development helps in
A. Formation of blood cells
B. Forming fingers by eliminating cells between digits
C. Building muscle tissue
D. producing hormones
Solution:
B. Forming fingers by eliminating cells between digits
(B) The root tip contains actively dividing cells in the apical meristem, making it ideal for observing all stages of mitosis under a microscope. Other options have fewer actively dividing cells.
Cell The Building Block of Life Class 9 Assertion and Reason Questions
Direction (Q.Nos. 1 – 9) In each of the following questions, a statement of Assertion (A) is given by the corresponding statement of Reason (R). Of the statements, mark the correct answer as
A. A and R are true, and R is the correct explanation of A
B. A and R are true, but R is not the correct explanation of A
C. A is true, but R is false
D. A is false, but R is true
Question 1.
Assertion (A): Rudolf Virchow proposed cell theory.
Reason (R): Cell theory states that all plants and animals are composed of cells.
Solution:
(D) A is false, but R is true.
A can be corrected as ‘All plant and animals are composed of cells’. This statement was presented as cell theory by Schleiden and Schwann (1838-39). Rudolf Virchow modified and expanded this earlier theory by suggesting that all cells arise from pre-existing cells.
Question 2.
Assertion (A) Chromosomes are constituted by DNA and proteins.
Reason (R): These are thread-like structures present in nucleus.
Solution:
(B) A and R are true, but R is not the correct explanation of A.
Chromosomes are the structures made up of DNA and proteins (i.e., histones). These are thread- like structures present in nucleus of the cell and contain genetic information that is transferred from parents to next generation.
Question 3.
Assertion (A): Prokaryotic cells are primitive and larger than eukaryotic cells.
Reason (R): Prokaryotic cells lack cytoplasmic organelles.
Solution:
(D) A is false, but R is true.
A can be corrected as Prokaryotic cells are smaller in size as compared to eukaryotic cells. These cells also lack cytoplasmic membrane-bound organelles. Thus, most functions are performed by poorly developed parts of cytoplasm.
Question 4.
Assertion (A): Golgi bodies store, modify, and pack products in vesicles.
Reason (R) Golgi bodies are involved in the formation of lysosomes.
Solution:
(B) A and R are true, but R is not the correct explanation of A.
Golgi bodies store, modify, and pack products (proteins) in vesicles, which are distributed to various parts of the cell. The Golgi bodies are also involved in the formation of lysosomes (waste disposal system of the cell).
Question 5.
Assertion (A): Mitochondria are known as the powerhouse of a cell.
Reason (R): Mitochondria generate energy (as ATP) for various cellular activities.
Solution:
(A) A and R are true, and R is the correct explanation of A.
Mitochondria are the sites of cellular respiration. The help to generate energy required by the cell in the form of ATP which gets utilised in cellular functions. That is why mitochondria are also known as power house of the cell.
Question 6.
Assertion (A) Robert Brown discovered nucleus.
Reason (R) Nucleoplasm and cytoplasm of a living cell together form the protoplasm.
Solution:
(B) Both A and R are true, but R is not the correct explanation of A.
Robert Brown discovered the nucleus. The fact that the nucleoplasm and cytoplasm together form the protoplasm is true, but it does not explain the discovery of the nucleus.
Question 7.
Assertion (A) Lysosomes are often called as ‘suicidal bags of a cell’.
Reason (R): Lysosomes contain hydrolytic enzymes capable of digesting cellular waste.
Solution:
(A) Both A and R are true, and R is the correct explanation of A.
Lysosomes are called ‘suicidal bags’ because they contain hydrolytic enzymes that can digest worn-out cell parts and cellular waste, explaining their self-destructive potential.
Question 8.
Assertion (A): Chromoplasts are coloured plastids.
Reason (R): Chromoplasts do not take part in photosynthesis.
Solution:
(B) Both A and R are true, but R is not the correct explanation of A.
Chromoplasts are coloured because they have pigments. They do help in pollination and seed dispersal, but that is not the reason they are coloured.
Question 9.
Assertion (A) Vacuoles are large sized in plant cell, but small sized in animal cell.
Reason (R) In plant cell, vacuoles are full of fluid from inside.
Solution:
(B) Both A and R are true, but R is not the correct explanation of A.
Vacuoles are large in plant cells because they store cell sap, which is a fluid containing water, sugars, and other substances from outside the cell. In animal cells, vacuoles are small as they do not store much fluid.