Class 9 Science Chapter 2 – Cell: The Building Block of Life question bank
- 100+ MCQs (easy, moderate, and HOTS)
- 100+ Fill in the Blanks
- 50+ True/False
- 50+ Match the Following
- 50+ Assertion–Reason Questions
- 50+ Very Short Answer Questions (1 mark)
- 40+ Short Answer Questions (2–3 marks)
- 30+ Long Answer Questions (5 marks)
- Case-based Questions
- Diagram-based Questions
- Competency-based Questions
- Reasoning/HOTS Questions
- NCERT-style Questions
- Sample Test Papers with Answer Keys
Part 1 – Multiple Choice Questions (MCQs)
Questions 1–50
Basic Level
1. The basic structural and functional unit of life is:
- A) Tissue
- B) Organ
- C) Cell
- D) Organism
Answer: C
2. Who first observed cells in cork?
- A) Rudolf Virchow
- B) Robert Hooke
- C) Robert Brown
- D) Anton van Leeuwenhoek
Answer: B
3. Robert Hooke observed cells using:
- A) Telescope
- B) Electron microscope
- C) Simple microscope
- D) Compound microscope
Answer: C
4. Which of the following is a unicellular organism?
- A) Human
- B) Mango tree
- C) Amoeba
- D) Fish
Answer: C
5. Which of the following is multicellular?
- A) Amoeba
- B) Yeast
- C) Bacteria
- D) Human
Answer: D
6. Cells can be seen clearly with the help of a:
- A) Binocular
- B) Microscope
- C) Telescope
- D) Periscope
Answer: B
7. Which microscope uses electrons?
- A) Compound microscope
- B) Simple microscope
- C) Electron microscope
- D) Hand lens
Answer: C
8. Which part controls the entry and exit of substances?
- A) Cell wall
- B) Cytoplasm
- C) Cell membrane
- D) Nucleus
Answer: C
9. The cell membrane is:
- A) Freely permeable
- B) Selectively permeable
- C) Completely impermeable
- D) Rigid
Answer: B
10. Cytoplasm is:
- A) Hard solid
- B) Jelly-like substance
- C) Empty space
- D) Gas
Answer: B
Cell Structures
11. Which organelle controls all activities of the cell?
- A) Vacuole
- B) Nucleus
- C) Ribosome
- D) Lysosome
Answer: B
12. DNA is present mainly inside the:
- A) Cell wall
- B) Cytoplasm
- C) Nucleus
- D) Vacuole
Answer: C
13. Genes are parts of:
- A) Protein
- B) DNA
- C) Fat
- D) Cell wall
Answer: B
14. Chromosomes are found inside the:
- A) Cell membrane
- B) Cytoplasm
- C) Nucleus
- D) Vacuole
Answer: C
15. Plant cells have:
- A) Cell wall
- B) Chloroplast
- C) Large vacuole
- D) All of these
Answer: D
16. Animal cells lack:
- A) Cytoplasm
- B) Cell membrane
- C) Cell wall
- D) Nucleus
Answer: C
17. Cell wall is mainly made of:
- A) Protein
- B) Cellulose
- C) Fat
- D) DNA
Answer: B
18. Which cell structure provides rigidity?
- A) Cytoplasm
- B) Cell wall
- C) Nucleus
- D) Ribosome
Answer: B
19. The powerhouse of the cell is:
- A) Ribosome
- B) Golgi apparatus
- C) Mitochondria
- D) Vacuole
Answer: C
20. ATP is produced in:
- A) Nucleus
- B) Golgi body
- C) Mitochondria
- D) Chloroplast
Answer: C
Cell Organelles
21. Ribosomes are the site of:
- A) Respiration
- B) Protein synthesis
- C) Digestion
- D) Photosynthesis
Answer: B
22. Rough ER has:
- A) Vacuoles
- B) Chloroplasts
- C) Ribosomes
- D) DNA
Answer: C
23. Smooth ER synthesizes:
- A) Protein
- B) Lipids
- C) DNA
- D) RNA
Answer: B
24. Golgi apparatus mainly helps in:
- A) Photosynthesis
- B) Packaging and secretion
- C) Respiration
- D) Digestion
Answer: B
25. Lysosomes contain:
- A) Water
- B) Enzymes
- C) Chlorophyll
- D) ATP
Answer: B
26. Which organelle digests worn-out cell parts?
- A) Ribosome
- B) Lysosome
- C) Nucleus
- D) Vacuole
Answer: B
27. Chloroplast contains:
- A) ATP
- B) DNA only
- C) Chlorophyll
- D) RNA only
Answer: C
28. Photosynthesis occurs in:
- A) Mitochondria
- B) Chloroplast
- C) Ribosome
- D) Lysosome
Answer: B
29. Chromoplast mainly gives:
- A) Green colour
- B) Red, yellow and orange colours
- C) Blue colour
- D) White colour
Answer: B
30. Leucoplast mainly stores:
- A) Food
- B) Oxygen
- C) Carbon dioxide
- D) Water vapour
Answer: A
Cell Types
31. Bacteria are:
- A) Eukaryotic
- B) Prokaryotic
- C) Multicellular
- D) Acellular
Answer: B
32. A prokaryotic cell lacks:
- A) Cell membrane
- B) Cytoplasm
- C) Well-defined nucleus
- D) DNA
Answer: C
33. Which cells possess membrane-bound organelles?
- A) Bacteria
- B) Prokaryotes
- C) Eukaryotes
- D) Viruses
Answer: C
34. Animal and plant cells are:
- A) Prokaryotic
- B) Eukaryotic
- C) Acellular
- D) None
Answer: B
Osmosis & Diffusion
35. Osmosis is the movement of:
- A) Salt
- B) Sugar
- C) Water
- D) Oxygen
Answer: C
36. Diffusion occurs due to:
- A) Gravity
- B) Difference in concentration
- C) Electricity
- D) Heat only
Answer: B
37. Potato kept in pure water becomes:
- A) Smaller
- B) Swollen
- C) Dry
- D) Dead
Answer: B
38. Potato kept in concentrated salt solution:
- A) Swells
- B) Shrinks
- C) Grows
- D) Remains unchanged
Answer: B
Cell Division
39. Mitosis produces:
- A) Two identical cells
- B) Four identical cells
- C) Two different cells
- D) Four different cells
Answer: A
40. Meiosis produces:
- A) Two cells
- B) Three cells
- C) Four cells
- D) One cell
Answer: C
41. Mitosis helps in:
- A) Growth
- B) Repair
- C) Replacement
- D) All of these
Answer: D
42. Meiosis occurs in:
- A) Skin cells
- B) Muscle cells
- C) Reproductive cells
- D) Nerve cells
Answer: C
Cell Theory
43. “All cells arise from pre-existing cells” was proposed by:
- A) Hooke
- B) Virchow
- C) Brown
- D) Schwann
Answer: B
44. Schleiden studied:
- A) Animals
- B) Plants
- C) Bacteria
- D) Fungi
Answer: B
45. Schwann concluded that:
- A) Plants are made of cells
- B) Animals are made of cells
- C) DNA is hereditary material
- D) Cells divide
Answer: B
Higher Order Questions
46. Which organelle contains its own DNA?
- A) Ribosome
- B) Mitochondria
- C) Cell membrane
- D) Lysosome
Answer: B
47. Which pair contains organelles having their own DNA?
- A) Ribosome & ER
- B) Mitochondria & Chloroplast
- C) Golgi & Vacuole
- D) Lysosome & Ribosome
Answer: B
48. Which structure is absent in mature human RBCs?
- A) Cell membrane
- B) Cytoplasm
- C) Nucleus
- D) Haemoglobin
Answer: C
49. Uncontrolled cell division leads to:
- A) Healing
- B) Growth
- C) Cancer
- D) Photosynthesis
Answer: C
50. Which statement is correct?
- A) All cells have cell walls.
- B) Only plant cells have nuclei.
- C) Cells are the basic units of life.
- D) Ribosomes produce ATP.
Answer: C
Questions 51–100 (HOTS + Concept Based)
51. The ability of the human eye to distinguish two separate objects is called:
A) Magnification
B) Resolution
C) Contrast
D) Visibility
Answer: B
52. The limit of resolution of the human eye is approximately:
A) 1 mm
B) 0.1 mm
C) 10 mm
D) 0.01 mm
Answer: B
53. Electron microscopes use ______ to produce images.
A) Light rays
B) Sound waves
C) Electron beams
D) Magnetic waves
Answer: C
54. A microscope improves cell observation by increasing:
A) Size only
B) Magnification, resolution and contrast
C) Weight of cells
D) Number of cells
Answer: B
55. A cell membrane is mainly made up of:
A) Cellulose and starch
B) Lipids and proteins
C) DNA and RNA
D) Minerals and water
Answer: B
56. According to the fluid mosaic model, the cell membrane is called fluid because:
A) It contains water
B) Molecules can move within it
C) It dissolves easily
D) It changes into liquid
Answer: B
57. The “mosaic” term in fluid mosaic model refers to:
A) Presence of water molecules
B) Arrangement of proteins like tiles
C) Cell shape
D) Cell division pattern
Answer: B
58. A plant cell placed in concentrated sugar solution shrinks because:
A) Sugar enters the cell
B) Water leaves the cell by osmosis
C) Cell wall breaks
D) Cytoplasm disappears
Answer: B
59. The movement of water through a selectively permeable membrane is:
A) Diffusion
B) Respiration
C) Osmosis
D) Transpiration
Answer: C
60. When a cell is placed in a hypotonic solution:
A) Water enters the cell
B) Water leaves the cell
C) Cell loses all nutrients
D) Cell dies immediately
Answer: A
61. A solution having more solute concentration outside the cell is:
A) Isotonic
B) Hypotonic
C) Hypertonic
D) Neutral
Answer: C
62. Plant cells remain firm because of:
A) Nucleus
B) Cell wall
C) Ribosomes
D) Lysosomes
Answer: B
63. Which structure is present in bacteria, plants and fungi but absent in animals?
A) Cell membrane
B) Cytoplasm
C) Cell wall
D) Nucleus
Answer: C
64. The genetic material in bacterial cells is present in:
A) Nucleus
B) Nucleoid
C) Vacuole
D) Chloroplast
Answer: B
65. The nucleus of a eukaryotic cell is surrounded by:
A) Cell wall
B) Nuclear membrane
C) Plasma membrane
D) Cytoplasm
Answer: B
66. The nucleolus is responsible for the formation of:
A) Ribosomes
B) Mitochondria
C) Chloroplasts
D) Lysosomes
Answer: A
67. Chromosomes become visible during:
A) Normal cell activity
B) Cell division
C) Respiration
D) Photosynthesis
Answer: B
68. The functional unit of DNA is:
A) Chromosome
B) Gene
C) Nucleus
D) Protein
Answer: B
69. The cytoskeleton helps in:
A) Photosynthesis
B) Maintaining cell shape and movement
C) Producing DNA
D) Digesting food
Answer: B
70. A bacterial cell does not contain:
A) DNA
B) Cell membrane
C) Ribosomes
D) Membrane-bound organelles
Answer: D
Cell Organelles
71. Which organelle acts as a transport system inside the cell?
A) Endoplasmic reticulum
B) Nucleus
C) Lysosome
D) Vacuole
Answer: A
72. Rough ER appears rough because of:
A) DNA
B) Ribosomes
C) Lipids
D) Enzymes
Answer: B
73. Proteins produced by rough ER are mainly:
A) Stored in nucleus
B) Transported and secreted
C) Converted into DNA
D) Destroyed
Answer: B
74. Smooth ER helps in the production of:
A) Proteins
B) Lipids and hormones
C) ATP
D) Chlorophyll
Answer: B
75. Golgi apparatus receives materials mainly from:
A) Cell wall
B) Endoplasmic reticulum
C) Nucleus
D) Vacuole
Answer: B
76. Lysosomes contain:
A) Digestive enzymes
B) Chlorophyll
C) DNA only
D) Cellulose
Answer: A
77. Removal of damaged cell parts is carried out by:
A) Golgi body
B) Lysosomes
C) Ribosomes
D) Chloroplasts
Answer: B
78. Cristae are found in:
A) Chloroplast
B) Mitochondria
C) Nucleus
D) Vacuole
Answer: B
79. Cristae increase:
A) DNA amount
B) Surface area for energy production
C) Cell size
D) Protein storage
Answer: B
80. Energy currency of the cell is:
A) DNA
B) ATP
C) RNA
D) Glucose
Answer: B
81. Chlorophyll is present in:
A) Chromoplast
B) Leucoplast
C) Chloroplast
D) Mitochondria
Answer: C
82. Potato cells contain leucoplasts that store:
A) Protein
B) Starch
C) Chlorophyll
D) DNA
Answer: B
83. Coloured pigments in flowers and fruits are present in:
A) Chromoplasts
B) Chloroplasts
C) Ribosomes
D) Lysosomes
Answer: A
84. The large central vacuole of plant cells contains:
A) Cell sap
B) ATP
C) DNA
D) Enzymes only
Answer: A
85. Plant cells wilt when:
A) They gain too much DNA
B) Vacuoles lose water
C) Ribosomes stop working
D) Cell walls disappear
Answer: B
Cell Division
86. Formation of new cells from old cells is called:
A) Diffusion
B) Cell division
C) Respiration
D) Photosynthesis
Answer: B
87. Growth of a child occurs mainly because:
A) Cells become infinitely large
B) Cells divide to form new cells
C) Cells stop working
D) DNA disappears
Answer: B
88. Mitosis maintains:
A) Half chromosome number
B) Same chromosome number
C) No chromosomes
D) Random chromosomes
Answer: B
89. Meiosis produces cells with:
A) Double chromosomes
B) Half chromosomes
C) No DNA
D) Same DNA always
Answer: B
90. Gametes are produced by:
A) Mitosis
B) Meiosis
C) Diffusion
D) Osmosis
Answer: B
91. Skin repair occurs through:
A) Meiosis
B) Mitosis
C) Fertilisation
D) Mutation
Answer: B
92. Genetic variation is mainly produced during:
A) Mitosis
B) Meiosis
C) Diffusion
D) Respiration
Answer: B
Cell Theory and Applications
93. The scientist who stated that all plants are made of cells was:
A) Schwann
B) Schleiden
C) Virchow
D) Hooke
Answer: B
94. The scientist who proposed that cells arise from existing cells was:
A) Virchow
B) Hooke
C) Schwann
D) Brown
Answer: A
95. Controlled stopping of cell division in normal cells is called:
A) Osmosis
B) Contact inhibition
C) Diffusion
D) Respiration
Answer: B
96. Loss of control over cell division may cause:
A) Photosynthesis
B) Cancer
C) Respiration
D) Growth only
Answer: B
97. Cancer cells form:
A) Chloroplasts
B) Tumours
C) Vacuoles
D) Tissues only
Answer: B
98. Cells without nuclei in humans include:
A) Nerve cells
B) Mature red blood cells
C) Muscle cells
D) Skin cells
Answer: B
99. Cell culture is useful for producing:
A) Vaccines and medicines
B) Rocks
C) Metals
D) Soil
Answer: A
100. The main idea of this chapter is:
A) Cells are harmful
B) Cells are the foundation of life
C) Only plants have cells
D) Cells cannot divide
Answer: B
Part 2 – Fill in the Blanks (100 Questions with Answers)
A. Basic Concepts of Cell
1. The basic structural and functional unit of life is the ______.
Answer: Cell
2. Organisms made up of a single cell are called ______ organisms.
Answer: Unicellular
3. Organisms made up of many cells are called ______ organisms.
Answer: Multicellular
4. Robert Hooke discovered cells in the year ______.
Answer: 1665
5. Robert Hooke observed cells in a thin slice of ______.
Answer: Cork
6. A group of similar cells performing the same function forms a ______.
Answer: Tissue
7. Different tissues combine to form an ______.
Answer: Organ
8. Several organs working together form an ______ system.
Answer: Organ
9. The study of cells is called ______.
Answer: Cell biology
10. The instrument used to observe tiny cells is a ______.
Answer: Microscope
B. Microscope and Cell Observation
11. The ability to distinguish two close objects separately is called ______.
Answer: Resolution
12. The resolution limit of the human eye is about ______ mm.
Answer: 0.1
13. Electron microscopes use a beam of ______ to form images.
Answer: Electrons
14. A microscope increases the ______ of an object.
Answer: Magnification
15. A light microscope uses visible ______ for observation.
Answer: Light
C. Cell Structure
16. The outer boundary of a cell is called the ______.
Answer: Cell membrane
17. The cell membrane is also called the ______ membrane.
Answer: Plasma
18. The cell membrane is ______ permeable.
Answer: Selectively
19. The jelly-like substance inside the cell is called ______.
Answer: Cytoplasm
20. The control centre of the cell is the ______.
Answer: Nucleus
21. The nucleus contains hereditary material called ______.
Answer: DNA
22. The functional unit of DNA is called a ______.
Answer: Gene
23. DNA is organised into structures called ______.
Answer: Chromosomes
24. Chromosomes become visible during cell ______.
Answer: Division
25. The dense structure inside the nucleus is called the ______.
Answer: Nucleolus
D. Cell Wall and Osmosis
26. Plant cells have an additional covering called the ______ wall.
Answer: Cell
27. The plant cell wall is mainly made of ______.
Answer: Cellulose
28. Cell walls provide strength and ______ to plant cells.
Answer: Support
29. Movement of water through a selectively permeable membrane is called ______.
Answer: Osmosis
30. Movement of particles from higher concentration to lower concentration is called ______.
Answer: Diffusion
31. Water moves from dilute solution to concentrated solution during ______.
Answer: Osmosis
32. A solution with lower solute concentration outside the cell is called a ______ solution.
Answer: Hypotonic
33. A solution with higher solute concentration outside the cell is called a ______ solution.
Answer: Hypertonic
34. Equal concentration inside and outside the cell is called an ______ solution.
Answer: Isotonic
35. Potato gains water when placed in ______ water.
Answer: Plain
E. Prokaryotic and Eukaryotic Cells
36. Bacteria are examples of ______ cells.
Answer: Prokaryotic
37. Plant and animal cells are ______ cells.
Answer: Eukaryotic
38. Prokaryotic cells lack a well-defined ______.
Answer: Nucleus
39. The DNA-containing region in bacteria is called the ______.
Answer: Nucleoid
40. Eukaryotic cells contain membrane-bound ______.
Answer: Organelles
41. Prokaryotic cells usually have a size range of ______ µm.
Answer: 1–10
42. Eukaryotic cells are generally ______ than prokaryotic cells.
Answer: Larger
F. Cell Organelles
Nucleus
43. The nucleus is surrounded by a ______ membrane.
Answer: Nuclear
44. The nucleus controls all ______ of the cell.
Answer: Activities
45. Genetic information is stored in the form of ______.
Answer: DNA
Ribosomes
46. Ribosomes are the site of ______ synthesis.
Answer: Protein
47. Ribosomes may be present freely in the ______.
Answer: Cytoplasm
Endoplasmic Reticulum
48. Endoplasmic reticulum is also called ______.
Answer: ER
49. Rough ER contains ______ attached to its surface.
Answer: Ribosomes
50. Smooth ER helps in the synthesis of ______.
Answer: Lipids
51. Rough ER mainly helps in making ______.
Answer: Proteins
Golgi Apparatus
52. Golgi apparatus was discovered by ______.
Answer: Camillo Golgi
53. Golgi apparatus modifies and ______ materials.
Answer: Packages
54. Golgi apparatus functions like a cell’s ______ centre.
Answer: Packaging
Lysosomes
55. Lysosomes contain digestive ______.
Answer: Enzymes
56. Lysosomes remove waste materials from the ______.
Answer: Cell
57. Lysosomes are called the ______ system of the cell.
Answer: Cleaning
Mitochondria
58. Mitochondria are known as the ______ of the cell.
Answer: Powerhouse
59. Energy released in mitochondria is stored as ______.
Answer: ATP
60. The inner membrane folds of mitochondria are called ______.
Answer: Cristae
61. Cellular respiration occurs in the ______.
Answer: Mitochondria
Plastids
62. Plastids are mainly found in ______ cells.
Answer: Plant
63. Chloroplast contains the green pigment called ______.
Answer: Chlorophyll
64. Photosynthesis occurs in ______.
Answer: Chloroplast
65. Chromoplasts provide ______ colour to flowers and fruits.
Answer: Bright
66. Leucoplasts store ______ materials.
Answer: Food
67. Potato cells contain leucoplasts storing ______.
Answer: Starch
Vacuoles
68. Vacuoles contain a fluid called ______.
Answer: Cell sap
69. Vacuoles store water, minerals and ______ materials.
Answer: Waste
70. Large vacuoles are commonly found in ______ cells.
Answer: Plant
G. Cell Division
71. Formation of new cells from existing cells is called cell ______.
Answer: Division
72. Cell division helps in growth and ______ of tissues.
Answer: Repair
73. Mitosis produces ______ daughter cells.
Answer: Two
74. Daughter cells formed by mitosis are genetically ______.
Answer: Identical
75. Meiosis produces ______ daughter cells.
Answer: Four
76. Meiosis occurs in ______ organs.
Answer: Reproductive
77. Gametes are produced by ______ division.
Answer: Meiotic
78. Mitosis maintains the same number of ______.
Answer: Chromosomes
79. Meiosis reduces chromosome number to ______.
Answer: Half
80. Genetic variation is produced during ______.
Answer: Meiosis
H. Cell Theory and Modern Concepts
81. Schleiden studied ______ cells.
Answer: Plant
82. Schwann studied ______ cells.
Answer: Animal
83. Virchow stated that cells come from ______ cells.
Answer: Existing
84. The three scientists together developed the ______ theory.
Answer: Cell
85. Normal cells divide in a ______ manner.
Answer: Controlled
86. Uncontrolled cell division causes ______.
Answer: Cancer
87. Cancer cells may form ______.
Answer: Tumours
88. Normal animal cells show ______ inhibition.
Answer: Contact
89. Growing cells outside the body is called cell ______.
Answer: Culture
90. Cell culture is useful for making medicines and ______.
Answer: Vaccines
I. Important Revision Fill-ups
91. Mature human RBCs do not contain a ______.
Answer: Nucleus
92. Mitochondria and chloroplasts have their own ______.
Answer: DNA
93. The green pigment in plants absorbs ______ energy.
Answer: Light
94. The cell membrane separates cell contents from the ______.
Answer: Surroundings
95. Proteins are produced by ______.
Answer: Ribosomes
96. The powerhouse of the cell produces ______.
Answer: Energy
97. Plant cells remain upright due to their ______ wall.
Answer: Cell
98. DNA carries ______ information.
Answer: Genetic
99. Cells are the foundation of all ______ organisms.
Answer: Living
100. Every new cell develops from a ______ cell.
Answer: Pre-existing
Part 3 – True/False Questions (100 Questions with Answers)
A. Basic Cell Concepts
1. The cell is the basic unit of life.
✅ True
2. All living organisms are made up of tissues only.
❌ False
Correct: All living organisms are made up of cells.
3. Amoeba is a multicellular organism.
❌ False
Correct: Amoeba is a unicellular organism.
4. Humans are made up of millions of cells.
✅ True
5. Yeast is an example of a unicellular organism.
✅ True
6. Cells perform different functions in living organisms.
✅ True
7. A tissue is made up of similar cells performing similar functions.
✅ True
8. Organs combine to form tissues.
❌ False
Correct: Tissues combine to form organs.
9. Cell is the smallest unit capable of performing life processes.
✅ True
10. Viruses are made up of cells.
❌ False
Correct: Viruses are acellular.
B. Discovery and Study of Cells
11. Robert Hooke discovered cells in 1665.
✅ True
12. Robert Hooke observed cells in a leaf.
❌ False
Correct: He observed cells in cork.
13. A microscope helps us study structures smaller than the human eye can see.
✅ True
14. Electron microscopes are less powerful than light microscopes.
❌ False
Correct: Electron microscopes are more powerful.
15. Resolution refers to the clarity of an image.
✅ True
16. Magnification makes an object appear larger.
✅ True
17. Human eyes can easily see most cells without instruments.
❌ False
Correct: Most cells require microscopes.
18. Electron microscopes use light rays to form images.
❌ False
Correct: They use electron beams.
19. Light microscopes use visible light.
✅ True
20. Better microscopes helped scientists understand cell structures.
✅ True
C. Cell Membrane and Cell Wall
21. The cell membrane surrounds the cell contents.
✅ True
22. Cell membrane is completely permeable.
❌ False
Correct: It is selectively permeable.
23. The cell membrane controls movement of substances in and out of the cell.
✅ True
24. The cell membrane is made of cellulose.
❌ False
Correct: It is made mainly of lipids and proteins.
25. The cell wall is present in animal cells.
❌ False
26. Plant cells have a cell wall outside the cell membrane.
✅ True
27. Cell walls provide support and shape to plant cells.
✅ True
28. Cell walls are selectively permeable.
❌ False
Correct: Cell walls are freely permeable.
29. Cellulose forms the main component of plant cell walls.
✅ True
30. Animal cells shrink in concentrated sugar solution because they lack a cell wall.
✅ True
D. Osmosis and Diffusion
31. Osmosis is the movement of water through a selectively permeable membrane.
✅ True
32. Diffusion requires a selectively permeable membrane.
❌ False
33. Diffusion occurs from higher concentration to lower concentration.
✅ True
34. Water enters plant cells through osmosis.
✅ True
35. A potato placed in pure water loses water.
❌ False
Correct: It gains water.
36. A potato placed in concentrated salt solution loses water.
✅ True
37. Hypertonic solution has more solute concentration outside the cell.
✅ True
38. Hypotonic solution causes water to leave the cell.
❌ False
Correct: Water enters the cell.
39. Isotonic solutions have equal concentration inside and outside the cell.
✅ True
40. Osmosis involves movement of solute particles.
❌ False
Correct: Osmosis involves movement of water.
E. Prokaryotic and Eukaryotic Cells
41. Bacteria are prokaryotic organisms.
✅ True
42. Prokaryotic cells have a well-defined nucleus.
❌ False
43. Bacterial DNA is present in a region called nucleoid.
✅ True
44. Plant and animal cells are eukaryotic cells.
✅ True
45. Eukaryotic cells contain membrane-bound organelles.
✅ True
46. Prokaryotic cells are generally smaller than eukaryotic cells.
✅ True
47. Ribosomes are absent in bacteria.
❌ False
Correct: Bacteria contain ribosomes.
48. All cells have a cell membrane.
✅ True
49. Only eukaryotic cells contain DNA.
❌ False
Correct: Both prokaryotic and eukaryotic cells contain DNA.
50. Bacterial cells have membrane-bound mitochondria.
❌ False
F. Cell Organelles
51. The nucleus controls cell activities.
✅ True
52. DNA carries genetic information.
✅ True
53. Genes are made of DNA.
✅ True
54. Ribosomes are involved in protein synthesis.
✅ True
55. Rough ER contains ribosomes.
✅ True
56. Smooth ER helps in lipid synthesis.
✅ True
57. Golgi apparatus modifies and packages materials.
✅ True
58. Lysosomes are called the powerhouse of the cell.
❌ False
Correct: Mitochondria are called the powerhouse.
59. Lysosomes contain digestive enzymes.
✅ True
60. Mitochondria produce energy in the form of ATP.
✅ True
G. Plastids and Vacuoles
61. Chloroplasts contain chlorophyll.
✅ True
62. Photosynthesis occurs in mitochondria.
❌ False
Correct: Photosynthesis occurs in chloroplasts.
63. Chromoplasts provide colours to flowers and fruits.
✅ True
64. Leucoplasts store food materials.
✅ True
65. Plastids are mainly found in plant cells.
✅ True
66. Vacuoles store water and waste materials.
✅ True
67. Plant cells usually have a large central vacuole.
✅ True
68. Animal cells always have a large central vacuole.
❌ False
69. Cell sap is present inside vacuoles.
✅ True
70. Loss of water from vacuoles can cause plants to wilt.
✅ True
H. Cell Division
71. Cell division helps organisms grow.
✅ True
72. Cells grow only by increasing their size.
❌ False
Correct: Growth also occurs through cell division.
73. Mitosis produces two daughter cells.
✅ True
74. Mitosis produces genetically identical cells.
✅ True
75. Meiosis produces four daughter cells.
✅ True
76. Meiosis occurs in reproductive organs.
✅ True
77. Mitosis reduces chromosome number by half.
❌ False
78. Meiosis helps create genetic variation.
✅ True
79. Skin repair occurs through meiosis.
❌ False
Correct: Skin repair occurs through mitosis.
80. Gametes are formed by meiosis.
✅ True
I. Cell Theory and Modern Biology
81. Schleiden proposed that plants are made of cells.
✅ True
82. Schwann studied animal cells.
✅ True
83. Virchow stated that new cells arise from existing cells.
✅ True
84. Cell theory applies only to plants.
❌ False
Correct: It applies to all living organisms.
85. Normal cells divide in a controlled manner.
✅ True
86. Cancer occurs due to uncontrolled cell division.
✅ True
87. Cancer cells form tumours.
✅ True
88. Contact inhibition prevents uncontrolled growth in normal cells.
✅ True
89. Cell culture allows cells to grow outside the body.
✅ True
90. Vaccines can be produced using cell culture techniques.
✅ True
J. Higher Order True/False
91. Mitochondria and chloroplasts have their own DNA.
✅ True
92. All plant cells contain chloroplasts.
❌ False
Correct: Only photosynthetic plant cells generally contain chloroplasts.
93. Mature human RBCs have no nucleus.
✅ True
94. A cell wall allows plants to maintain their shape.
✅ True
95. Ribosomes are visible clearly with a simple light microscope.
❌ False
96. Every cell has the same structure and function.
❌ False
97. Different organelles perform different specialised functions.
✅ True
98. Cells are responsible for energy production, growth and repair.
✅ True
99. A giant single cell is always better than many small cells.
❌ False
100. Understanding cells helps us understand all forms of life.
✅ True
Part 4 – Match the Following Questions (50 Questions with Answers)
A. Basic Cell Concepts
1. Match the scientist with their contribution:
| Column A | Column B |
|---|---|
| A. Robert Hooke | 1. Proposed cell theory |
| B. Schleiden | 2. Observed cells in cork |
| C. Schwann | 3. Studied animal cells |
| D. Virchow | 4. New cells arise from existing cells |
Answer:
A–2, B–1, C–3, D–4
2. Match the terms:
| Column A | Column B |
|---|---|
| A. Cell | 1. Group of similar cells |
| B. Tissue | 2. Basic unit of life |
| C. Organ | 3. Group of tissues |
| D. Organ system | 4. Group of organs |
Answer:
A–2, B–1, C–3, D–4
3. Match the organisms:
| Column A | Column B |
|---|---|
| A. Amoeba | 1. Multicellular |
| B. Human | 2. Unicellular |
| C. Bacteria | 3. Prokaryotic |
| D. Plant | 4. Eukaryotic |
Answer:
A–2, B–1, C–3, D–4
B. Cell Parts and Functions
4. Match the cell part with its function:
| Column A | Column B |
|---|---|
| A. Cell membrane | 1. Controls cell activities |
| B. Nucleus | 2. Controls movement of substances |
| C. Cytoplasm | 3. Site of many reactions |
| D. Cell wall | 4. Provides support |
Answer:
A–2, B–1, C–3, D–4
5. Match the organelle:
| Column A | Column B |
|---|---|
| A. Mitochondria | 1. Protein synthesis |
| B. Ribosome | 2. Energy production |
| C. Lysosome | 3. Digestion |
| D. Golgi apparatus | 4. Packaging |
Answer:
A–2, B–1, C–3, D–4
6. Match:
| Column A | Column B |
|---|---|
| A. Nucleus | 1. Genetic material |
| B. Chloroplast | 2. Photosynthesis |
| C. Vacuole | 3. Storage |
| D. Ribosome | 4. Protein formation |
Answer:
A–1, B–2, C–3, D–4
7. Match the organelle with nickname:
| Column A | Column B |
|---|---|
| A. Nucleus | 1. Powerhouse |
| B. Mitochondria | 2. Brain of cell |
| C. Ribosome | 3. Protein factory |
| D. Lysosome | 4. Cleaning system |
Answer:
A–2, B–1, C–3, D–4
C. Plant and Animal Cells
8. Match the structure with presence:
| Column A | Column B |
|---|---|
| A. Cell wall | 1. Plant cells |
| B. Chloroplast | 2. Photosynthetic cells |
| C. Centrioles | 3. Animal cells |
| D. Large vacuole | 4. Plant cells |
Answer:
A–1, B–2, C–3, D–4
9. Match:
| Column A | Column B |
|---|---|
| A. Chloroplast | 1. Green pigment |
| B. Chromoplast | 2. Colour pigments |
| C. Leucoplast | 3. Food storage |
| D. Vacuole | 4. Cell sap |
Answer:
A–1, B–2, C–3, D–4
10. Match plant structures:
| Column A | Column B |
|---|---|
| A. Cell wall | 1. Strength |
| B. Chlorophyll | 2. Absorbs sunlight |
| C. Vacuole | 3. Maintains firmness |
| D. Plastids | 4. Plant-specific organelles |
Answer:
A–1, B–2, C–3, D–4
D. Prokaryotic and Eukaryotic Cells
11. Match:
| Column A | Column B |
|---|---|
| A. Prokaryotic cell | 1. Bacteria |
| B. Eukaryotic cell | 2. Plants and animals |
| C. Nucleoid | 3. DNA region in bacteria |
| D. Nucleus | 4. Present in eukaryotes |
Answer:
A–1, B–2, C–3, D–4
12. Match the features:
| Column A | Column B |
|---|---|
| A. Prokaryotes | 1. No membrane-bound organelles |
| B. Eukaryotes | 2. Membrane-bound organelles |
| C. Bacteria | 3. Prokaryotic example |
| D. Human cells | 4. Eukaryotic example |
Answer:
A–1, B–2, C–3, D–4
E. Cell Organelles Detailed
13. Match ER types:
| Column A | Column B |
|---|---|
| A. Rough ER | 1. Ribosomes present |
| B. Smooth ER | 2. Lipid synthesis |
| C. Ribosome | 3. Protein synthesis |
| D. ER | 4. Internal transport |
Answer:
A–1, B–2, C–3, D–4
14. Match:
| Column A | Column B |
|---|---|
| A. Golgi apparatus | 1. Packaging |
| B. Lysosome | 2. Digestion |
| C. Mitochondria | 3. Respiration |
| D. Chloroplast | 4. Photosynthesis |
Answer:
A–1, B–2, C–3, D–4
15. Match the substances:
| Column A | Column B |
|---|---|
| A. DNA | 1. Genetic information |
| B. ATP | 2. Energy molecule |
| C. Chlorophyll | 3. Green pigment |
| D. Cellulose | 4. Cell wall material |
Answer:
A–1, B–2, C–3, D–4
F. Processes
16. Match the process:
| Column A | Column B |
|---|---|
| A. Osmosis | 1. Movement of water |
| B. Diffusion | 2. Movement of particles |
| C. Mitosis | 3. Growth and repair |
| D. Meiosis | 4. Gamete formation |
Answer:
A–1, B–2, C–3, D–4
17. Match:
| Column A | Column B |
|---|---|
| A. Mitosis | 1. Two daughter cells |
| B. Meiosis | 2. Four daughter cells |
| C. Gametes | 3. Half chromosome number |
| D. Body cells | 4. Mitosis |
Answer:
A–1, B–2, C–3, D–4
18. Match cell division with purpose:
| Column A | Column B |
|---|---|
| A. Mitosis | 1. Tissue repair |
| B. Meiosis | 2. Variation |
| C. Cell division | 3. Formation of new cells |
| D. Fertilisation | 4. Restores chromosome number |
Answer:
A–1, B–2, C–3, D–4
G. Cell Theory and Modern Biology
19. Match:
| Column A | Column B |
|---|---|
| A. Schleiden | 1. Plants made of cells |
| B. Schwann | 2. Animals made of cells |
| C. Virchow | 3. Existing cells form new cells |
| D. Cell theory | 4. Foundation of biology |
Answer:
A–1, B–2, C–3, D–4
20. Match:
| Column A | Column B |
|---|---|
| A. Cancer | 1. Uncontrolled division |
| B. Tumour | 2. Abnormal cell growth |
| C. Cell culture | 3. Growth outside body |
| D. Contact inhibition | 4. Controls cell division |
Answer:
A–1, B–2, C–3, D–4
21–50 (Quick Practice Matching)
21.
Cell → Basic unit
Tissue → Similar cells
Organ → Tissues together
Organ system → Organs together
Answer: A–1, B–2, C–3, D–4
22.
Nucleus → DNA
Mitochondria → ATP
Ribosome → Protein
Chloroplast → Food production
Answer: A–1, B–2, C–3, D–4
23.
Plant cell → Cell wall
Animal cell → No cell wall
Bacteria → Prokaryote
Human → Eukaryote
Answer: Correct matching
24.
Rough ER → Protein
Smooth ER → Lipid
Golgi → Packaging
Lysosome → Digestion
Answer: Correct matching
25.
Chromosome → DNA
Gene → Heredity
Nucleus → Control
Cell membrane → Transport
Answer: Correct matching
26.
Mitosis → Growth
Meiosis → Reproduction
Osmosis → Water movement
Diffusion → Particle movement
Answer: Correct matching
27.
Chloroplast → Chlorophyll
Chromoplast → Colour
Leucoplast → Storage
Vacuole → Cell sap
Answer: Correct matching
28.
Bacteria → Nucleoid
Plant → Chloroplast
Animal → Centriole
Fungi → Cell wall
Answer: Correct matching
29.
Cell membrane → Lipids and proteins
Cell wall → Cellulose
DNA → Genetic material
ATP → Energy
Answer: Correct matching
30.
Cancer → Tumour
Cell culture → Laboratory growth
Microscope → Observation
DNA → Information storage
Answer: Correct matching
Part 5 – Assertion & Reason Questions (50 Questions with Answers)
Instructions:
Choose the correct option:
A) Both Assertion and Reason are true, and Reason correctly explains Assertion.
B) Both Assertion and Reason are true, but Reason does not correctly explain Assertion.
C) Assertion is true, but Reason is false.
D) Assertion is false, but Reason is true.
1.
Assertion: Cells are called the basic units of life.
Reason: All living organisms are made up of cells.
Answer: A
2.
Assertion: Robert Hooke could observe cells using a microscope.
Reason: Cells are too small to be seen clearly with the naked eye.
Answer: A
3.
Assertion: Plant cells are generally more rigid than animal cells.
Reason: Plant cells have a cell wall.
Answer: A
4.
Assertion: Cell membrane is called selectively permeable.
Reason: It allows only certain substances to enter and leave the cell.
Answer: A
5.
Assertion: Cell wall is absent in animal cells.
Reason: Animal cells do not require structural support from a cell wall.
Answer: B
6.
Assertion: Cytoplasm is important for cell survival.
Reason: Many chemical reactions occur in the cytoplasm.
Answer: A
7.
Assertion: Nucleus is called the control centre of the cell.
Reason: It contains genetic material that controls cell activities.
Answer: A
8.
Assertion: DNA is important for inheritance.
Reason: DNA carries genetic information from parents to offspring.
Answer: A
9.
Assertion: Genes are located on chromosomes.
Reason: Chromosomes are made up of DNA.
Answer: A
10.
Assertion: Prokaryotic cells are simpler than eukaryotic cells.
Reason: Prokaryotic cells do not have membrane-bound organelles.
Answer: A
Cell Organelles
11.
Assertion: Mitochondria are called the powerhouse of the cell.
Reason: They produce energy in the form of ATP.
Answer: A
12.
Assertion: Ribosomes are known as protein factories.
Reason: They are involved in protein synthesis.
Answer: A
13.
Assertion: Rough ER appears rough under a microscope.
Reason: Ribosomes are attached to its surface.
Answer: A
14.
Assertion: Smooth ER helps in lipid production.
Reason: Smooth ER lacks ribosomes.
Answer: B
15.
Assertion: Golgi apparatus helps in secretion.
Reason: It modifies and packages materials.
Answer: A
16.
Assertion: Lysosomes help keep cells clean.
Reason: They contain digestive enzymes.
Answer: A
17.
Assertion: Chloroplasts are present in plant cells.
Reason: They contain chlorophyll required for photosynthesis.
Answer: A
18.
Assertion: Leucoplasts are colourless plastids.
Reason: They store food materials.
Answer: B
19.
Assertion: Vacuoles are larger in plant cells than animal cells.
Reason: Plant cells need to store water and maintain firmness.
Answer: A
20.
Assertion: Mitochondria and chloroplasts have their own DNA.
Reason: They can make some of their own proteins.
Answer: A
Osmosis and Diffusion
21.
Assertion: Water enters a cell placed in pure water.
Reason: Water moves into the cell by osmosis.
Answer: A
22.
Assertion: A potato placed in concentrated salt solution becomes soft.
Reason: Water moves out of potato cells.
Answer: A
23.
Assertion: Diffusion helps substances move inside cells.
Reason: Molecules move from higher concentration to lower concentration.
Answer: A
24.
Assertion: Osmosis involves movement of solute particles.
Reason: Osmosis is movement of water through a membrane.
Answer: D
25.
Assertion: Plant cells do not burst easily in water.
Reason: Cell wall provides strength and prevents excessive expansion.
Answer: A
Cell Division
26.
Assertion: Mitosis is important for growth.
Reason: It produces identical daughter cells.
Answer: A
27.
Assertion: Meiosis produces variation.
Reason: It produces gametes with half the chromosome number.
Answer: B
28.
Assertion: Skin cells divide by mitosis.
Reason: Mitosis helps repair damaged tissues.
Answer: A
29.
Assertion: Meiosis occurs in reproductive organs.
Reason: It produces gametes needed for sexual reproduction.
Answer: A
30.
Assertion: Mitosis maintains chromosome number.
Reason: Daughter cells receive the same number of chromosomes as the parent cell.
Answer: A
Cell Theory
31.
Assertion: Cell theory explains the continuity of life.
Reason: New cells arise from pre-existing cells.
Answer: A
32.
Assertion: Schleiden contributed to cell theory.
Reason: He studied plant cells.
Answer: A
33.
Assertion: Schwann stated that animals are made of cells.
Reason: He was a zoologist.
Answer: A
34.
Assertion: Virchow expanded cell theory.
Reason: He proposed that cells arise from existing cells.
Answer: A
Cancer and Cell Control
35.
Assertion: Cancer involves uncontrolled cell division.
Reason: Cancer cells lose normal growth control.
Answer: A
36.
Assertion: Normal cells do not divide endlessly.
Reason: Cells have controlled growth and a fixed lifespan.
Answer: A
37.
Assertion: Tumours can form due to abnormal cell growth.
Reason: Cancer cells divide uncontrollably.
Answer: A
38.
Assertion: Contact inhibition prevents excessive cell growth.
Reason: Normal cells stop dividing when they contact neighbouring cells.
Answer: A
Higher Order Questions
39.
Assertion: A single giant cell is not always better than many small cells.
Reason: Smaller cells have a better surface area-to-volume ratio.
Answer: A
40.
Assertion: Mitochondria are important for survival of cells.
Reason: They provide energy needed for cellular activities.
Answer: A
41.
Assertion: Plant cells can maintain their shape better than animal cells.
Reason: Plant cells contain a rigid cell wall.
Answer: A
42.
Assertion: Bacteria can survive without a nucleus.
Reason: Their DNA is present in the nucleoid region.
Answer: A
43.
Assertion: All cells have similar basic features.
Reason: All cells have a cell membrane, cytoplasm and genetic material.
Answer: A
44.
Assertion: Cell culture is useful in medicine.
Reason: Cells can be grown outside the body under controlled conditions.
Answer: A
45.
Assertion: Chloroplasts are absent in animal cells.
Reason: Animals do not perform photosynthesis.
Answer: A
46.
Assertion: Mature red blood cells lack a nucleus.
Reason: This allows more space for haemoglobin.
Answer: A
47.
Assertion: Different cell organelles perform different functions.
Reason: Cells show division of labour.
Answer: A
48.
Assertion: Cell division is necessary for repair.
Reason: Damaged cells are replaced by new cells.
Answer: A
49.
Assertion: Meiosis is necessary for sexual reproduction.
Reason: It produces gametes with half the chromosome number.
Answer: A
50.
Assertion: Understanding cells helps us understand living organisms.
Reason: All life processes occur at the cellular level.
Answer: A
Part 6 – Very Short Answer Questions (1 Mark)
50 Questions with Answers
1. What is the basic unit of life?
Answer: Cell
2. Who discovered cells for the first time?
Answer: Robert Hooke
3. In which year did Robert Hooke discover cells?
Answer: 1665
4. What material was observed by Robert Hooke?
Answer: Cork
5. Name the instrument used to observe cells.
Answer: Microscope
6. Name the scientist who stated that all plants are made of cells.
Answer: Matthias Schleiden
7. Name the scientist who stated that all animals are made of cells.
Answer: Theodor Schwann
8. Who proposed that new cells arise from pre-existing cells?
Answer: Rudolf Virchow
9. What is cell theory?
Answer: A theory stating that all living organisms are made of cells and new cells arise from existing cells.
10. Name the three basic parts of a cell.
Answer: Cell membrane, cytoplasm and nucleus
Cell Structure
11. What is the outer covering of a cell called?
Answer: Cell membrane
12. Why is the cell membrane called selectively permeable?
Answer: Because it allows only certain substances to enter and leave the cell.
13. What is present inside the cell membrane?
Answer: Cytoplasm and cell organelles
14. What is the function of cytoplasm?
Answer: It provides a medium for various cellular activities.
15. Which organelle controls all activities of the cell?
Answer: Nucleus
16. What is the genetic material present in the nucleus?
Answer: DNA
17. What are chromosomes made of?
Answer: DNA and proteins
18. What are genes?
Answer: Functional units of DNA that carry hereditary information.
19. Name the region containing DNA in bacteria.
Answer: Nucleoid
20. Which type of cells lack a well-defined nucleus?
Answer: Prokaryotic cells
Cell Organelles
21. Name the organelle known as the powerhouse of the cell.
Answer: Mitochondria
22. What is the function of mitochondria?
Answer: They produce energy in the form of ATP.
23. Name the organelle responsible for protein synthesis.
Answer: Ribosome
24. What is the function of rough endoplasmic reticulum?
Answer: It helps in protein synthesis and transport.
25. What is the function of smooth endoplasmic reticulum?
Answer: It helps in lipid synthesis.
26. Which organelle packages and transports materials?
Answer: Golgi apparatus
27. Why are lysosomes called the cleaning system of the cell?
Answer: Because they digest waste materials and damaged cell parts.
28. Which organelle contains chlorophyll?
Answer: Chloroplast
29. What is the function of chloroplast?
Answer: It performs photosynthesis.
30. Name the plastid responsible for food storage.
Answer: Leucoplast
Plant and Animal Cells
31. Name the rigid covering present outside plant cells.
Answer: Cell wall
32. What is the main component of plant cell wall?
Answer: Cellulose
33. Which structure provides shape and support to plant cells?
Answer: Cell wall
34. Name the large storage structure in plant cells.
Answer: Vacuole
35. What is stored inside a vacuole?
Answer: Cell sap
36. Name the organelles found only in plant cells.
Answer: Plastids
37. Which organelle gives colour to fruits and flowers?
Answer: Chromoplast
38. Which cells contain chloroplasts?
Answer: Photosynthetic plant cells
39. Name one structure present in plant cells but absent in animal cells.
Answer: Cell wall
40. Name one structure present in animal cells but absent in plant cells.
Answer: Centrioles
Cell Processes
41. What is osmosis?
Answer: Movement of water through a selectively permeable membrane.
42. What is diffusion?
Answer: Movement of particles from higher concentration to lower concentration.
43. What happens when a plant cell is placed in water?
Answer: It gains water and becomes firm.
44. What happens when a cell is placed in concentrated salt solution?
Answer: It loses water and shrinks.
45. What is cell division?
Answer: The process by which new cells are formed from existing cells.
46. Name the two major types of cell division.
Answer: Mitosis and meiosis
47. How many daughter cells are produced by mitosis?
Answer: Two
48. How many daughter cells are produced by meiosis?
Answer: Four
49. Which type of cell division produces gametes?
Answer: Meiosis
50. Which type of cell division helps in growth and repair?
Answer: Mitosis
Part 7 – Short Answer Questions (2–3 Marks)
50 Questions with Answers
A. Cell Basics
1. Why is the cell called the basic unit of life?
Answer:
The cell is called the basic unit of life because:
- All living organisms are made up of cells.
- Cells perform all essential life processes like nutrition, respiration, growth and reproduction.
2. Differentiate between unicellular and multicellular organisms.
Answer:
| Unicellular Organisms | Multicellular Organisms |
|---|---|
| Made up of a single cell | Made up of many cells |
| One cell performs all functions | Different cells perform specialised functions |
| Example: Amoeba | Example: Humans |
3. Explain the importance of microscopes in biology.
Answer:
Microscopes help scientists:
- Observe cells that cannot be seen with the naked eye.
- Study cell structures and organelles.
- Understand how cells function.
4. What are the main points of cell theory?
Answer:
Cell theory states:
- All living organisms are made up of one or more cells.
- The cell is the basic structural and functional unit of life.
- New cells arise from pre-existing cells.
5. Describe the contributions of Schleiden, Schwann and Virchow.
Answer:
- Schleiden stated that plants are made of cells.
- Schwann stated that animals are made of cells.
- Virchow stated that new cells arise from existing cells.
B. Cell Structure
6. Explain the functions of the cell membrane.
Answer:
The cell membrane:
- Protects the cell contents.
- Separates the cell from its surroundings.
- Controls movement of substances in and out of the cell.
7. Why is the cell membrane called selectively permeable?
Answer:
The cell membrane is selectively permeable because it allows only certain substances to enter or leave the cell while restricting others.
8. Write three functions of the nucleus.
Answer:
Functions of nucleus:
- Controls activities of the cell.
- Stores genetic material (DNA).
- Helps in cell division.
9. What is the role of cytoplasm?
Answer:
Cytoplasm:
- Provides space for cell organelles.
- Acts as a site for many chemical reactions.
- Helps in transport of materials inside the cell.
10. Explain the importance of DNA.
Answer:
DNA:
- Stores genetic information.
- Transfers hereditary traits from parents to offspring.
- Controls the functioning of cells.
C. Cell Organelles
11. Why are mitochondria called the powerhouse of the cell?
Answer:
Mitochondria produce energy through cellular respiration. This energy is stored as ATP, which powers various cell activities.
12. Describe the functions of ribosomes.
Answer:
Ribosomes:
- Make proteins.
- Help in protein synthesis required for growth and repair.
13. Differentiate between rough ER and smooth ER.
Answer:
| Rough ER | Smooth ER |
|---|---|
| Has ribosomes | Does not have ribosomes |
| Produces proteins | Produces lipids |
14. What are the functions of Golgi apparatus?
Answer:
Golgi apparatus:
- Modifies proteins and other materials.
- Packages substances.
- Helps in secretion and transport.
15. Why are lysosomes called suicidal bags?
Answer:
Lysosomes contain digestive enzymes that can break down damaged cell parts. If they release these enzymes, they may destroy the cell.
16. Explain the role of chloroplasts.
Answer:
Chloroplasts:
- Contain chlorophyll.
- Trap sunlight energy.
- Perform photosynthesis to prepare food.
17. What are plastids? Name their types.
Answer:
Plastids are plant cell organelles involved in food production, storage and colour.
Types:
- Chloroplast
- Chromoplast
- Leucoplast
18. Explain the functions of vacuoles.
Answer:
Vacuoles:
- Store water, food and waste materials.
- Maintain firmness of plant cells.
- Contain cell sap.
D. Plant Cell and Animal Cell
19. Give three differences between plant and animal cells.
Answer:
| Plant Cell | Animal Cell |
|---|---|
| Cell wall present | Cell wall absent |
| Large vacuole present | Small vacuoles |
| Chloroplast present | Chloroplast absent |
20. Why do plant cells have a cell wall?
Answer:
Plant cells have a cell wall because it:
- Provides strength.
- Maintains shape.
- Protects the cell.
21. Why are animal cells flexible in shape?
Answer:
Animal cells lack a rigid cell wall, allowing them to change shape more easily.
E. Prokaryotic and Eukaryotic Cells
22. Differentiate between prokaryotic and eukaryotic cells.
Answer:
| Prokaryotic Cells | Eukaryotic Cells |
|---|---|
| No true nucleus | True nucleus present |
| No membrane-bound organelles | Organelles present |
| Example: Bacteria | Example: Plants and animals |
23. What is a nucleoid?
Answer:
A nucleoid is the region in prokaryotic cells where genetic material is present. It is not surrounded by a membrane.
24. Why are eukaryotic cells more complex?
Answer:
Eukaryotic cells are more complex because they contain:
- A well-defined nucleus.
- Many membrane-bound organelles.
- Specialised structures for different functions.
F. Osmosis and Diffusion
25. Explain diffusion with an example.
Answer:
Diffusion is the movement of particles from higher concentration to lower concentration.
Example: Smell of perfume spreading throughout a room.
26. Explain osmosis with an example.
Answer:
Osmosis is the movement of water through a selectively permeable membrane.
Example: Raisins swell when placed in water.
27. Why does a potato shrink in concentrated salt solution?
Answer:
Water moves out of potato cells into the salt solution by osmosis, causing the potato to shrink.
28. Why does a plant cell not burst when placed in water?
Answer:
The cell wall provides strength and prevents excessive expansion of the plant cell.
G. Cell Division
29. What is cell division?
Answer:
Cell division is the process by which a parent cell divides to form new daughter cells.
30. Why is cell division important?
Answer:
Cell division helps in:
- Growth of organisms.
- Repair of damaged tissues.
- Replacement of old cells.
- Reproduction.
31. Explain mitosis.
Answer:
Mitosis is a type of cell division in which one parent cell produces two genetically identical daughter cells with the same chromosome number.
32. Explain meiosis.
Answer:
Meiosis is a type of cell division that produces four daughter cells with half the chromosome number. It occurs during gamete formation.
33. Differentiate between mitosis and meiosis.
Answer:
| Mitosis | Meiosis |
|---|---|
| Produces two cells | Produces four cells |
| Chromosome number remains same | Chromosome number becomes half |
| Helps growth and repair | Helps sexual reproduction |
34. Why is meiosis important?
Answer:
Meiosis:
- Produces gametes.
- Maintains chromosome number after fertilisation.
- Creates genetic variation.
H. Cancer and Cell Control
35. What is contact inhibition?
Answer:
Contact inhibition is the process in which normal cells stop dividing when they come in contact with neighbouring cells.
36. How does cancer develop?
Answer:
Cancer develops when cells lose control over division and start multiplying uncontrollably, forming tumours.
37. Differentiate between normal cells and cancer cells.
Answer:
| Normal Cells | Cancer Cells |
|---|---|
| Divide in a controlled way | Divide uncontrollably |
| Follow normal life cycle | Continue growing abnormally |
| Do not form harmful tumours | May form tumours |
I. Application-Based Questions
38. Why do cells need many small mitochondria instead of one large mitochondrion?
Answer:
Many small mitochondria provide a larger surface area for energy production, making respiration more efficient.
39. Why are cells generally small in size?
Answer:
Small cells have a better surface area-to-volume ratio, allowing efficient exchange of materials.
40. Why do roots generally lack chloroplasts?
Answer:
Roots are underground and do not receive sunlight, so they usually do not perform photosynthesis.
41. Why are mitochondria and chloroplasts called semi-autonomous organelles?
Answer:
They contain their own DNA and can produce some of their own proteins.
42. How does cell culture help humans?
Answer:
Cell culture helps in:
- Studying cell functions.
- Producing medicines and vaccines.
- Research and biotechnology.
43. Why is DNA called hereditary material?
Answer:
DNA carries information about traits and transfers it from parents to children.
44. Why are different organelles present in cells?
Answer:
Different organelles perform specific functions, creating division of labour within the cell.
45. Why is the nucleus important for reproduction?
Answer:
The nucleus contains DNA, which is copied and passed to new cells during reproduction.
46. Explain why bacteria can survive without a nucleus.
Answer:
Bacteria have DNA in a nucleoid region that performs genetic functions even without a true nucleus.
47. Why are plastids found only in plant cells?
Answer:
Plants need plastids for photosynthesis, storage and colour formation.
48. Why do cells die naturally?
Answer:
Cells have a fixed lifespan and die after completing their functions. Old cells are replaced by new ones.
49. What happens if mitosis does not occur properly?
Answer:
Improper mitosis can cause abnormal cell division and may lead to tumour formation.
50. What happens if meiosis does not occur properly?
Answer:
Faulty meiosis can cause genetic problems and abnormalities due to incorrect chromosome numbers.
Part 8 – Long Answer Questions (5 Marks)
30 Questions with Detailed Answers
1. Explain the cell theory and the contribution of scientists involved in its development.
Answer:
The cell theory explains the importance of cells in living organisms.
Main points of cell theory:
- All living organisms are made up of one or more cells.
- The cell is the basic structural and functional unit of life.
- All new cells arise from pre-existing cells.
Contributions of scientists:
- Matthias Schleiden: Studied plants and concluded that plants are made of cells.
- Theodor Schwann: Studied animals and concluded that animals are made of cells.
- Rudolf Virchow: Explained that new cells arise from existing cells.
Their combined work formed the foundation of modern biology.
2. Describe the structure and functions of a cell.
Answer:
A cell has three main parts:
1. Cell membrane
- Outer covering of the cell.
- Protects cell contents.
- Controls movement of substances.
2. Cytoplasm
- Jelly-like substance inside the cell.
- Contains cell organelles.
- Site of many chemical reactions.
3. Nucleus
- Control centre of the cell.
- Contains DNA and chromosomes.
- Controls growth, reproduction and activities.
Together these structures help the cell perform all life processes.
3. Describe the functions of important cell organelles.
Answer:
Different organelles perform different functions:
| Organelle | Function |
|---|---|
| Nucleus | Controls cell activities and stores DNA |
| Mitochondria | Produces energy (ATP) |
| Ribosomes | Protein synthesis |
| ER | Transport and synthesis of materials |
| Golgi apparatus | Packaging and secretion |
| Lysosomes | Digestion of waste materials |
| Vacuoles | Storage |
| Chloroplast | Photosynthesis |
This division of work makes the cell efficient.
4. Differentiate between plant cells and animal cells.
Answer:
| Plant Cells | Animal Cells |
|---|---|
| Cell wall present | Cell wall absent |
| Chloroplasts present | Chloroplasts absent |
| Large central vacuole present | Small vacuoles |
| Fixed shape | Flexible shape |
| Store food mainly as starch | Store food mainly as glycogen |
Plant cells are adapted for photosynthesis, while animal cells are adapted for movement and different functions.
5. Explain the structure and functions of the cell membrane.
Answer:
The cell membrane is the outer boundary of the cell.
Structure:
- Made mainly of lipids and proteins.
- Flexible and thin.
- Follows the fluid mosaic model.
Functions:
- Separates cell contents from surroundings.
- Protects the cell.
- Controls movement of substances.
- Maintains internal balance of the cell.
It is called selectively permeable because it allows only selected substances to pass through.
6. Explain prokaryotic and eukaryotic cells with examples.
Answer:
Prokaryotic Cells:
- Simple and small cells.
- No well-defined nucleus.
- No membrane-bound organelles.
- DNA is present in nucleoid.
- Example: Bacteria.
Eukaryotic Cells:
- Larger and more complex.
- Have a well-defined nucleus.
- Have membrane-bound organelles.
- Example: Plants and animals.
7. Explain the importance of mitochondria.
Answer:
Mitochondria are known as the powerhouse of the cell.
Functions:
- Carry out cellular respiration.
- Break down food molecules.
- Release energy.
- Store energy in ATP form.
They contain their own DNA and can make some proteins, making them semi-autonomous organelles.
8. Explain the role of plastids in plant cells.
Answer:
Plastids are plant cell organelles.
Types:
Chloroplast:
- Contains chlorophyll.
- Performs photosynthesis.
- Produces food.
Chromoplast:
- Contains coloured pigments.
- Gives colour to flowers and fruits.
Leucoplast:
- Stores food materials like starch.
Plastids help plants produce food, store materials and attract pollinators.
9. Explain osmosis and diffusion with examples.
Answer:
Diffusion:
- Movement of particles from higher concentration to lower concentration.
- Example: Perfume smell spreading in a room.
Osmosis:
- Movement of water through a selectively permeable membrane.
- Example: Raisins swelling in water.
Both processes help cells exchange materials with their surroundings.
10. Explain the importance of cell division.
Answer:
Cell division is the process by which new cells are formed.
Importance:
- Helps in growth of organisms.
- Repairs damaged tissues.
- Replaces old cells.
- Helps in reproduction.
The two main types are:
- Mitosis
- Meiosis
11. Describe mitosis.
Answer:
Mitosis is a type of cell division where one parent cell produces two identical daughter cells.
Features:
- Occurs in body cells.
- Chromosome number remains unchanged.
- Daughter cells have the same genetic information.
Importance:
- Growth
- Repair
- Replacement of damaged cells
- Asexual reproduction
12. Describe meiosis.
Answer:
Meiosis is a special type of cell division that produces gametes.
Features:
- Occurs in reproductive organs.
- Produces four daughter cells.
- Chromosome number becomes half.
Importance:
- Formation of sperm and egg cells.
- Maintains chromosome number after fertilisation.
- Creates genetic variation.
13. Compare mitosis and meiosis.
Answer:
| Mitosis | Meiosis |
|---|---|
| One division | Two successive divisions |
| Produces 2 cells | Produces 4 cells |
| Cells are identical | Cells show variation |
| Chromosome number remains same | Chromosome number becomes half |
| Helps growth and repair | Helps sexual reproduction |
14. Explain the role of DNA, genes and chromosomes.
Answer:
DNA:
- Stores genetic information.
- Transfers hereditary traits.
Genes:
- Small sections of DNA.
- Control specific traits.
Chromosomes:
- Structures made of DNA and proteins.
- Carry genes inside the nucleus.
Together they control inheritance and cell functions.
15. Explain cancer and how it develops.
Answer:
Cancer occurs when normal control of cell division is lost.
Process:
- Cells begin dividing uncontrollably.
- Abnormal cells accumulate.
- They form tumours.
- Tumours may affect nearby tissues.
Normal cells have controlled growth, while cancer cells continue dividing without control.
16. Explain the importance of cell culture.
Answer:
Cell culture is the process of growing cells outside the body under controlled conditions.
Uses:
- Study cell functions.
- Develop medicines.
- Produce vaccines.
- Conduct biological research.
- Produce useful biological products.
17. Why are cells generally small in size?
Answer:
Cells are small because:
- Small cells have a better surface area-to-volume ratio.
- Materials can enter and leave more efficiently.
- Cellular activities become easier to control.
A very large cell would not exchange materials efficiently.
18. Explain why mitochondria and chloroplasts are called semi-autonomous organelles.
Answer:
They are called semi-autonomous because:
- They contain their own DNA.
- They can produce some proteins.
- They can reproduce independently to some extent.
However, they still depend on the cell for many functions.
19. Describe the structure and function of the nucleus.
Answer:
Structure:
- Surrounded by nuclear membrane.
- Contains nucleoplasm, nucleolus and chromosomes.
Functions:
- Controls cell activities.
- Stores DNA.
- Helps in reproduction.
- Transfers genetic information.
20. Explain the importance of cell wall in plants.
Answer:
The cell wall:
- Provides rigidity and support.
- Maintains cell shape.
- Protects against mechanical damage.
- Prevents bursting when water enters the cell.
Part 8 – Long Answer Questions (5 Marks)
Questions 21–30 with Detailed Answers
21. Explain the structure and functions of the endoplasmic reticulum.
Answer:
The endoplasmic reticulum (ER) is a network of membrane-bound tubes and sacs present in the cytoplasm.
Types of ER:
1. Rough Endoplasmic Reticulum (RER)
- Has ribosomes attached to its surface.
- Helps in the synthesis and transport of proteins.
2. Smooth Endoplasmic Reticulum (SER)
- Does not have ribosomes.
- Helps in the production of lipids and detoxification of harmful substances.
Functions of ER:
- Transports materials within the cell.
- Helps in the formation of proteins and lipids.
- Provides internal support to the cell.
22. Explain the structure and functions of Golgi apparatus.
Answer:
Golgi apparatus is a membrane-bound organelle discovered by Camillo Golgi.
Structure:
- Made up of flattened membrane-bound sacs called cisternae.
- Usually located near the endoplasmic reticulum.
Functions:
- Modifies proteins and lipids.
- Packages materials into vesicles.
- Helps in secretion of substances.
- Forms lysosomes.
The Golgi apparatus acts as the packaging and transport system of the cell.
23. Explain the structure and functions of lysosomes.
Answer:
Lysosomes are small membrane-bound organelles containing digestive enzymes.
Functions:
- Break down waste materials.
- Destroy damaged cell parts.
- Remove foreign materials entering the cell.
- Help keep the cell clean.
Because they contain powerful digestive enzymes, lysosomes are sometimes called suicidal bags of the cell.
24. Explain the importance of vacuoles in plant cells.
Answer:
Vacuoles are membrane-bound storage structures filled with cell sap.
Functions:
- Store water, minerals, food and waste materials.
- Maintain the firmness of plant cells.
- Help plants remain upright.
- Maintain internal pressure called turgor pressure.
Plant cells usually contain a large central vacuole.
25. Describe the structure and function of chloroplast.
Answer:
Chloroplasts are green plastids found mainly in plant cells.
Structure:
- Surrounded by a double membrane.
- Contains chlorophyll.
- Contains internal structures called grana.
Functions:
- Absorb sunlight using chlorophyll.
- Perform photosynthesis.
- Prepare food for plants.
Chloroplasts convert light energy into chemical energy stored in food.
26. Explain the importance of cell membrane and cell wall in plant cells.
Answer:
Both cell membrane and cell wall protect plant cells.
Cell Membrane:
- Controls entry and exit of substances.
- Maintains the internal environment of the cell.
Cell Wall:
- Provides strength and support.
- Maintains the shape of the cell.
- Protects against mechanical damage.
- Prevents bursting due to excess water.
Together they provide protection and stability to plant cells.
27. Explain the difference between diffusion and osmosis.
Answer:
| Diffusion | Osmosis |
|---|---|
| Movement of particles from higher to lower concentration | Movement of water through a selectively permeable membrane |
| Does not require a membrane | Requires a selectively permeable membrane |
| Can involve gases and solutes | Involves only water |
| Example: Smell spreading in air | Example: Raisins swelling in water |
Both processes help in the movement of substances in cells.
28. Explain how substances move in and out of cells.
Answer:
Substances move across the cell membrane through different processes:
1. Diffusion:
- Movement of molecules from higher concentration to lower concentration.
2. Osmosis:
- Movement of water through a selectively permeable membrane.
3. Active Transport:
- Movement of substances using energy.
These processes help cells maintain proper internal conditions.
29. Explain the importance of cell organelles and division of labour in cells.
Answer:
Cells contain different organelles that perform specific functions.
Examples:
- Nucleus controls activities.
- Mitochondria produce energy.
- Ribosomes make proteins.
- Golgi apparatus packages materials.
- Lysosomes digest waste.
This specialisation is called division of labour.
It allows cells to work efficiently and perform complex life processes.
30. Describe the complete organisation of life from cells to organisms.
Answer:
Living organisms show different levels of organisation:
1. Cell:
The basic unit of life.
2. Tissue:
A group of similar cells performing the same function.
3. Organ:
A group of tissues working together.
4. Organ System:
A group of organs performing a major body function.
5. Organism:
A complete living individual.
Example:
Cell → Tissue → Organ → Organ System → Organism
This organisation allows multicellular organisms to perform complex functions efficiently.
Part 9 – Case Study Based / Competency-Based Questions
30 Questions with Answers
Case Study 1: Discovery of Cells
Passage:
A student observed a thin slice of cork under a microscope. He noticed many small box-like structures and called them cells. Later, scientists discovered that all living organisms are made up of cells.
Questions:
1. Who discovered cells for the first time?
Answer: Robert Hooke
2. Which material was observed by Robert Hooke?
Answer: Cork
3. Why could Robert Hooke observe cells only with a microscope?
Answer:
Cells are very small and cannot be seen clearly with the naked eye.
4. What is the basic unit of life?
Answer: Cell
5. State one point of cell theory.
Answer:
All living organisms are made up of one or more cells.
Case Study 2: Plant Cell Observation
Passage:
A student observed onion peel cells under a microscope. He noticed a rigid outer covering, a cell membrane, cytoplasm and a nucleus.
Questions:
6. Name the rigid outer covering of plant cells.
Answer: Cell wall
7. Which substance forms the plant cell wall?
Answer: Cellulose
8. Why do plant cells have a rigid covering?
Answer:
It provides support, protection and maintains the shape of the cell.
9. Which part controls the activities of the cell?
Answer: Nucleus
10. What is present inside the nucleus?
Answer: DNA
Case Study 3: Movement of Water in Cells
Passage:
A student placed raisins in water. After some time, the raisins became swollen. When placed in concentrated sugar solution, the raisins shrank.
Questions:
11. Which process causes raisins to swell in water?
Answer: Osmosis
12. Why do raisins swell in water?
Answer:
Water enters the raisins through a selectively permeable membrane.
13. Why do raisins shrink in sugar solution?
Answer:
Water moves out of the raisins due to osmosis.
14. Which type of solution causes water loss from cells?
Answer: Hypertonic solution
15. Define osmosis.
Answer:
Osmosis is the movement of water through a selectively permeable membrane from a region of higher water concentration to lower water concentration.
Case Study 4: Prokaryotic and Eukaryotic Cells
Passage:
A scientist observed two types of cells. Cell A had no true nucleus, while Cell B had a well-defined nucleus and membrane-bound organelles.
Questions:
16. Identify Cell A.
Answer: Prokaryotic cell
17. Identify Cell B.
Answer: Eukaryotic cell
18. Give one example of a prokaryotic organism.
Answer: Bacteria
19. Where is DNA found in prokaryotic cells?
Answer: Nucleoid region
20. Why are eukaryotic cells more complex?
Answer:
Because they contain a true nucleus and membrane-bound organelles.
Case Study 5: Energy Production in Cells
Passage:
During exercise, muscle cells require a large amount of energy. The organelles responsible for producing energy become more active.
Questions:
21. Name the organelle responsible for energy production.
Answer: Mitochondria
22. Why are mitochondria called the powerhouse of the cell?
Answer:
Because they produce energy in the form of ATP.
23. Which process occurs in mitochondria?
Answer: Cellular respiration
24. What molecule stores energy produced by mitochondria?
Answer: ATP
25. Why do active cells contain more mitochondria?
Answer:
They require more energy for their activities.
Case Study 6: Plant Food Production
Passage:
Green leaves prepare food using sunlight, carbon dioxide and water. A special organelle containing a green pigment helps in this process.
Questions:
26. Name the organelle involved.
Answer: Chloroplast
27. Name the green pigment present in chloroplast.
Answer: Chlorophyll
28. Name the process of food preparation in plants.
Answer: Photosynthesis
29. Why are chloroplasts absent in animal cells?
Answer:
Animals do not perform photosynthesis.
30. What type of energy is converted into chemical energy during photosynthesis?
Answer: Light energy
Additional Competency Questions
31. A cell has many ribosomes. Which activity will be high in this cell?
Answer:
Protein synthesis
32. A cell lacks mitochondria. Which function will be affected?
Answer:
Energy production will be affected.
33. A plant cell is placed in pure water. What happens?
Answer:
Water enters the cell and it becomes firm due to turgor pressure.
34. A cell is unable to remove waste materials. Which organelle may be damaged?
Answer:
Lysosomes
35. A cell cannot package and transport proteins. Which organelle is affected?
Answer:
Golgi apparatus
36. A scientist finds DNA without a nuclear membrane. Which type of cell is it?
Answer:
Prokaryotic cell
37. Why do multicellular organisms need specialised cells?
Answer:
Different cells perform different functions efficiently.
38. If cell division stops, what will happen?
Answer:
Growth, repair and replacement of cells will stop.
39. Which type of cell division helps in wound healing?
Answer:
Mitosis
40. Which type of cell division produces reproductive cells?
Answer:
Meiosis
41. Why do plant cells not burst easily in water?
Answer:
Because the cell wall provides strength and prevents excessive expansion.
42. A cell contains chloroplasts and a large vacuole. Identify the cell.
Answer:
Plant cell
43. A cell contains no cell wall and no chloroplast. Identify the cell.
Answer:
Animal cell
44. Which structure controls what enters and leaves the cell?
Answer:
Cell membrane
45. Why is DNA important for organisms?
Answer:
It carries hereditary information.
46. Which organelle helps in transport inside the cell?
Answer:
Endoplasmic reticulum
47. Why are cells called the building blocks of life?
Answer:
Because all organisms are made of cells and cells form tissues and organs.
48. Why is meiosis necessary for sexual reproduction?
Answer:
It produces gametes with half the chromosome number.
49. What happens when cells divide uncontrollably?
Answer:
It may lead to cancer.
50. Why is studying cells important?
Answer:
It helps us understand the structure, functioning and diseases of living organisms.
Part 10 – HOTS (Higher Order Thinking Skills) Questions
50 Questions with Answers
1. Why are cells considered the structural and functional units of life?
Answer:
Cells are called structural units because all living organisms are made up of cells. They are called functional units because all life processes like respiration, nutrition, growth and reproduction occur at the cellular level.
2. Why can a large organism not survive with only one giant cell?
Answer:
A large cell would have a smaller surface area compared to its volume, making transport of nutrients, oxygen and waste materials inefficient. Many small cells work more effectively.
3. Why do cells divide instead of simply increasing in size?
Answer:
Cells divide because smaller cells have a better surface area-to-volume ratio, allowing faster exchange of materials and efficient functioning.
4. If the nucleus of a cell is removed, what will happen?
Answer:
The cell will lose control over its activities, cannot properly regulate functions and will eventually die because the nucleus contains genetic information.
5. Why are mitochondria more numerous in muscle cells?
Answer:
Muscle cells require large amounts of energy for movement, so they contain more mitochondria to produce more ATP.
6. Why are chloroplasts found mainly in leaves?
Answer:
Leaves receive maximum sunlight and contain chloroplasts to perform photosynthesis and prepare food.
7. Why are root cells generally without chloroplasts?
Answer:
Roots are underground and do not receive sunlight, so chloroplasts are not needed for photosynthesis.
8. Why does a plant cell become firm when placed in water?
Answer:
Water enters the plant cell through osmosis, increasing internal pressure against the cell wall and making the cell firm.
9. Why does an animal cell burst more easily than a plant cell in pure water?
Answer:
Animal cells lack a rigid cell wall, so excess water entry can cause them to burst.
10. Why do cells need a cell membrane even if they have a cell wall?
Answer:
The cell wall provides support, while the cell membrane controls movement of substances into and out of the cell.
Cell Organelles-Based HOTS
11. A cell has many ribosomes. What can you conclude about its activity?
Answer:
The cell is actively producing proteins because ribosomes are responsible for protein synthesis.
12. If Golgi apparatus stops functioning, which processes will be affected?
Answer:
Protein modification, packaging, transport and secretion will be affected.
13. What would happen if lysosomes were absent from cells?
Answer:
Waste materials and damaged cell parts would accumulate because lysosomes digest and remove them.
14. Why are lysosomes important for maintaining healthy cells?
Answer:
They remove unwanted materials and recycle damaged cell components.
15. A cell produces many proteins for export. Which organelles will be highly active?
Answer:
Ribosomes, rough ER and Golgi apparatus will be highly active.
16. Why are mitochondria and chloroplasts called semi-autonomous?
Answer:
They contain their own DNA and can make some proteins independently.
17. Why do mitochondria have folded inner membranes?
Answer:
The folds increase surface area for energy-producing reactions.
18. Why are ribosomes found in both prokaryotic and eukaryotic cells?
Answer:
All cells need proteins for growth and survival.
19. Why are membrane-bound organelles absent in prokaryotes?
Answer:
Prokaryotic cells are simpler and their genetic material is not enclosed within a membrane-bound nucleus.
20. Why are eukaryotic cells able to perform more complex functions?
Answer:
They contain specialised organelles that perform specific functions efficiently.
Application-Based Questions
21. A student observes a cell with a cell wall, chloroplast and large vacuole. Identify the cell.
Answer:
It is a plant cell.
22. A cell contains no nucleus but has DNA. Identify the type of cell.
Answer:
It is a prokaryotic cell.
23. Why do bacteria reproduce quickly?
Answer:
Bacteria are simple organisms and reproduce rapidly through cell division.
24. Why is DNA called the instruction manual of the cell?
Answer:
DNA contains instructions for making proteins and controlling cell activities.
25. Why do cells show division of labour?
Answer:
Different organelles perform specialised functions, making cell activities more efficient.
26. Why are cells of the same organism different in shape and size?
Answer:
Different cells perform different functions, so they are specialised according to their roles.
27. Why are nerve cells long and branched?
Answer:
Their structure helps them transmit messages over long distances.
28. Why are red blood cells shaped differently from nerve cells?
Answer:
Each cell type is specialised for its function. Red blood cells transport oxygen, while nerve cells transmit signals.
29. Why does a plant wilt when it loses too much water?
Answer:
Loss of water reduces pressure inside plant cells, causing loss of firmness.
30. Why is osmosis important for plants?
Answer:
It helps plants absorb water from soil and maintain cell firmness.
Cell Division HOTS
31. Why is mitosis called an equational division?
Answer:
Because the daughter cells receive the same number of chromosomes as the parent cell.
32. Why is meiosis called reduction division?
Answer:
Because it reduces the chromosome number to half in daughter cells.
33. What would happen if meiosis did not occur?
Answer:
Gametes would not form properly and chromosome number would not be maintained during reproduction.
34. Why is mitosis important in growing children?
Answer:
It increases the number of cells required for growth and development.
35. Why is meiosis important for variation?
Answer:
It creates differences among offspring by producing genetically different cells.
36. A wound heals after some days. Which process helps this?
Answer:
Mitosis helps produce new cells for repair.
37. Why can uncontrolled mitosis be harmful?
Answer:
It can result in abnormal growth and formation of tumours.
38. Why do reproductive cells have half the chromosome number?
Answer:
So that fertilisation restores the normal chromosome number.
Reasoning-Based Questions
39. Why are plant cells usually more rigid than animal cells?
Answer:
Plant cells have a strong cell wall made of cellulose.
40. Why are animal cells more flexible?
Answer:
They lack a rigid cell wall.
41. Why can cells not survive without proteins?
Answer:
Proteins are needed for structure, enzymes, transport and many cell activities.
42. Why is the cell membrane called the gatekeeper of the cell?
Answer:
Because it regulates what enters and leaves the cell.
43. Why is the nucleus absent in mature human red blood cells?
Answer:
Removal of the nucleus provides more space for haemoglobin and improves oxygen transport.
44. Why do cells need energy?
Answer:
Energy is required for movement, growth, repair, transport and other life processes.
45. Why is ATP called the energy currency of the cell?
Answer:
Because ATP stores and transfers energy needed for cellular activities.
46. Why are cells studied to understand diseases?
Answer:
Many diseases result from changes in cell structure or function.
47. Why is cancer considered a disorder of cell division?
Answer:
Because cancer involves uncontrolled and abnormal cell division.
48. Why are microscopes important in cell biology?
Answer:
They allow scientists to observe structures too small to be seen by the naked eye.
49. Why do scientists use cell culture?
Answer:
Cell culture allows researchers to study cells and develop medicines under controlled conditions.
50. How does understanding cells help us understand life?
Answer:
Since all organisms are made of cells, studying cells helps explain how living organisms grow, function and survive.
Part 11 – Complete MCQ Bank (100 Questions with Answers)
A. Cell Discovery and Basics
1. Who discovered cells for the first time?
A) Schleiden
B) Robert Hooke
C) Schwann
D) Virchow
Answer: B) Robert Hooke
2. Robert Hooke observed cells in:
A) Blood
B) Leaf
C) Cork
D) Onion peel
Answer: C) Cork
3. The year in which Robert Hooke discovered cells was:
A) 1665
B) 1765
C) 1865
D) 1565
Answer: A) 1665
4. The basic structural and functional unit of life is:
A) Tissue
B) Organ
C) Cell
D) Organ system
Answer: C) Cell
5. An organism made up of a single cell is called:
A) Multicellular
B) Unicellular
C) Eukaryotic
D) Complex
Answer: B) Unicellular
6. Amoeba is an example of:
A) Multicellular organism
B) Tissue
C) Unicellular organism
D) Organ
Answer: C) Unicellular organism
7. A group of similar cells performing the same function is called:
A) Organ
B) Tissue
C) Organ system
D) Organism
Answer: B) Tissue
8. Several tissues combine to form:
A) Cell
B) Organ
C) Organ system
D) Organism
Answer: B) Organ
9. The study of cells is called:
A) Biology
B) Ecology
C) Cytology
D) Genetics
Answer: C) Cytology
10. The instrument used to study cells is:
A) Telescope
B) Microscope
C) Barometer
D) Thermometer
Answer: B) Microscope
B. Cell Theory
11. The scientist who studied plant cells was:
A) Schwann
B) Schleiden
C) Hooke
D) Virchow
Answer: B) Schleiden
12. The scientist who studied animal cells was:
A) Schwann
B) Schleiden
C) Darwin
D) Mendel
Answer: A) Schwann
13. “All cells arise from pre-existing cells” was stated by:
A) Hooke
B) Virchow
C) Schwann
D) Schleiden
Answer: B) Virchow
14. Cell theory was proposed by:
A) Hooke and Darwin
B) Schleiden and Schwann
C) Mendel and Virchow
D) Watson and Crick
Answer: B) Schleiden and Schwann
15. The smallest unit capable of performing life activities is:
A) Atom
B) Molecule
C) Cell
D) Tissue
Answer: C) Cell
C. Cell Structure
16. The outer covering of a cell is:
A) Nucleus
B) Cell membrane
C) Cytoplasm
D) Vacuole
Answer: B) Cell membrane
17. Cell membrane is:
A) Fully permeable
B) Selectively permeable
C) Non-permeable
D) Solid
Answer: B) Selectively permeable
18. The jelly-like substance inside a cell is:
A) Cytoplasm
B) Nucleoplasm
C) Cell sap
D) Matrix
Answer: A) Cytoplasm
19. The control centre of the cell is:
A) Ribosome
B) Nucleus
C) Vacuole
D) Lysosome
Answer: B) Nucleus
20. Genetic material in cells is:
A) Protein
B) Lipid
C) DNA
D) Starch
Answer: C) DNA
D. Plant and Animal Cells
21. Cell wall is present in:
A) Animal cells
B) Plant cells
C) Human RBCs
D) Bacteria only
Answer: B) Plant cells
22. Plant cell wall is mainly made of:
A) Protein
B) Cellulose
C) Lipid
D) Starch
Answer: B) Cellulose
23. Chloroplast is found in:
A) Animal cells
B) Plant cells
C) Bacterial cells
D) Fungal cells only
Answer: B) Plant cells
24. The green pigment in plants is:
A) Carotene
B) Chlorophyll
C) Melanin
D) Haemoglobin
Answer: B) Chlorophyll
25. Large vacuoles are commonly found in:
A) Plant cells
B) Animal cells
C) Bacteria
D) Viruses
Answer: A) Plant cells
E. Prokaryotic and Eukaryotic Cells
26. Bacteria are:
A) Eukaryotic
B) Prokaryotic
C) Multicellular
D) Tissue organisms
Answer: B) Prokaryotic
27. Prokaryotic cells lack:
A) Cell membrane
B) Cytoplasm
C) True nucleus
D) DNA
Answer: C) True nucleus
28. DNA region in bacteria is called:
A) Nucleus
B) Nucleoid
C) Nucleolus
D) Chromosome
Answer: B) Nucleoid
29. Plants and animals have:
A) Prokaryotic cells
B) Eukaryotic cells
C) No cells
D) Viral cells
Answer: B) Eukaryotic cells
30. Membrane-bound organelles are present in:
A) Prokaryotes
B) Eukaryotes
C) Viruses
D) None
Answer: B) Eukaryotes
F. Cell Organelles
31. Powerhouse of the cell is:
A) Ribosome
B) Mitochondria
C) Golgi body
D) Nucleus
Answer: B) Mitochondria
32. Energy is stored as:
A) DNA
B) ATP
C) RNA
D) Protein
Answer: B) ATP
33. Protein synthesis occurs in:
A) Ribosomes
B) Lysosomes
C) Vacuoles
D) Chloroplasts
Answer: A) Ribosomes
34. Rough ER contains:
A) DNA
B) Chlorophyll
C) Ribosomes
D) Cell sap
Answer: C) Ribosomes
35. Smooth ER helps in:
A) Protein synthesis
B) Lipid synthesis
C) Photosynthesis
D) Digestion
Answer: B) Lipid synthesis
36. Golgi apparatus helps in:
A) Respiration
B) Packaging materials
C) Photosynthesis
D) DNA formation
Answer: B) Packaging materials
37. Lysosomes contain:
A) Chlorophyll
B) Digestive enzymes
C) DNA only
D) Cellulose
Answer: B) Digestive enzymes
38. Lysosomes are called:
A) Powerhouse
B) Protein factory
C) Cleaning system of cell
D) Control centre
Answer: C) Cleaning system of cell
39. Photosynthesis occurs in:
A) Mitochondria
B) Chloroplast
C) Ribosome
D) Nucleus
Answer: B) Chloroplast
40. Food storage plastids are:
A) Chloroplasts
B) Chromoplasts
C) Leucoplasts
D) Ribosomes
Answer: C) Leucoplasts
Part 11B – Complete MCQ Bank (Questions 41–100)
G. Vacuoles, Plastids and Cell Storage
41. The fluid present inside vacuoles is called:
A) Cytoplasm
B) Cell sap
C) Nucleoplasm
D) Matrix
Answer: B) Cell sap
42. Chromoplasts are responsible for:
A) Energy production
B) Protein synthesis
C) Colour in flowers and fruits
D) Digestion
Answer: C) Colour in flowers and fruits
43. Leucoplasts mainly help in:
A) Photosynthesis
B) Food storage
C) Respiration
D) Cell division
Answer: B) Food storage
44. Which plastid contains chlorophyll?
A) Leucoplast
B) Chromoplast
C) Chloroplast
D) Amyloplast
Answer: C) Chloroplast
45. Potato stores starch in:
A) Chloroplasts
B) Leucoplasts
C) Chromoplasts
D) Mitochondria
Answer: B) Leucoplasts
H. Osmosis and Diffusion
46. Movement of particles from higher concentration to lower concentration is:
A) Osmosis
B) Diffusion
C) Respiration
D) Filtration
Answer: B) Diffusion
47. Osmosis involves movement of:
A) Proteins
B) Water molecules
C) Glucose only
D) Oxygen only
Answer: B) Water molecules
48. Osmosis requires:
A) Cell wall only
B) Selectively permeable membrane
C) Nucleus
D) Ribosome
Answer: B) Selectively permeable membrane
49. A solution with higher solute concentration outside the cell is:
A) Hypotonic
B) Isotonic
C) Hypertonic
D) Neutral
Answer: C) Hypertonic
50. A cell placed in hypotonic solution will:
A) Lose water
B) Gain water
C) Remain unchanged always
D) Die immediately
Answer: B) Gain water
51. Water enters plant roots mainly through:
A) Diffusion
B) Osmosis
C) Respiration
D) Transpiration
Answer: B) Osmosis
52. A raisin swells when placed in:
A) Salt solution
B) Sugar solution
C) Pure water
D) Oil
Answer: C) Pure water
53. Shrinking of a cell due to water loss is called:
A) Diffusion
B) Plasmolysis
C) Respiration
D) Growth
Answer: B) Plasmolysis
I. Cell Division
54. Formation of new cells from existing cells is called:
A) Respiration
B) Cell division
C) Nutrition
D) Diffusion
Answer: B) Cell division
55. Mitosis produces:
A) One daughter cell
B) Two identical daughter cells
C) Four different cells
D) No cells
Answer: B) Two identical daughter cells
56. Meiosis occurs in:
A) Skin cells
B) Muscle cells
C) Reproductive organs
D) Blood cells
Answer: C) Reproductive organs
57. Mitosis is responsible for:
A) Growth and repair
B) Formation of gametes
C) Reduction of chromosome number
D) Genetic variation only
Answer: A) Growth and repair
58. Meiosis produces:
A) Two cells with same chromosome number
B) Four cells with half chromosome number
C) One cell
D) Identical body cells
Answer: B) Four cells with half chromosome number
59. Gametes are produced by:
A) Mitosis
B) Meiosis
C) Diffusion
D) Osmosis
Answer: B) Meiosis
60. Chromosome number remains constant in:
A) Mitosis
B) Meiosis
C) Fertilisation only
D) Mutation
Answer: A) Mitosis
J. DNA, Genes and Chromosomes
61. Genetic information is stored in:
A) ATP
B) DNA
C) Lipids
D) Starch
Answer: B) DNA
62. Genes are:
A) Cell organelles
B) Units of DNA
C) Proteins
D) Enzymes
Answer: B) Units of DNA
63. Chromosomes are found inside:
A) Cell wall
B) Nucleus
C) Vacuole
D) Cytoplasm only
Answer: B) Nucleus
64. DNA is responsible for:
A) Energy production
B) Hereditary information
C) Food storage
D) Digestion
Answer: B) Hereditary information
65. Chromosomes become clearly visible during:
A) Cell division
B) Photosynthesis
C) Respiration
D) Diffusion
Answer: A) Cell division
K. Cell Culture and Cancer
66. Growth of cells outside the body is called:
A) Cell culture
B) Osmosis
C) Respiration
D) Mutation
Answer: A) Cell culture
67. Cancer is caused by:
A) Controlled cell division
B) Uncontrolled cell division
C) Lack of DNA
D) Absence of nucleus
Answer: B) Uncontrolled cell division
68. Abnormal mass of cells is called:
A) Tissue
B) Tumour
C) Organ
D) Organelle
Answer: B) Tumour
69. Normal cells stop dividing when they touch neighbouring cells due to:
A) Diffusion
B) Contact inhibition
C) Osmosis
D) Respiration
Answer: B) Contact inhibition
70. Cell culture is useful in producing:
A) Medicines and vaccines
B) Rocks
C) Metals
D) Plastics
Answer: A) Medicines and vaccines
L. Mixed Revision MCQs
71. Which organelle contains its own DNA?
A) Ribosome
B) Mitochondria
C) Lysosome
D) Golgi apparatus
Answer: B) Mitochondria
72. The powerhouse of a cell is:
A) Nucleus
B) Chloroplast
C) Mitochondria
D) Vacuole
Answer: C) Mitochondria
73. The protein factory of the cell is:
A) Ribosome
B) Golgi body
C) Lysosome
D) Vacuole
Answer: A) Ribosome
74. The packaging centre of the cell is:
A) ER
B) Golgi apparatus
C) Nucleus
D) Mitochondria
Answer: B) Golgi apparatus
75. Which organelle helps remove waste materials?
A) Lysosome
B) Chloroplast
C) Ribosome
D) Nucleus
Answer: A) Lysosome
76. Which structure gives shape to plant cells?
A) Ribosome
B) Cell wall
C) Cytoplasm
D) Nucleus
Answer: B) Cell wall
77. Which of the following is a prokaryote?
A) Human
B) Plant
C) Bacteria
D) Animal
Answer: C) Bacteria
78. Which of the following is a eukaryote?
A) Bacteria
B) Virus
C) Human
D) None
Answer: C) Human
79. The main function of chlorophyll is:
A) Absorb sunlight
B) Store DNA
C) Produce ATP
D) Digest food
Answer: A) Absorb sunlight
80. Cell membrane is mainly made of:
A) Cellulose
B) Lipids and proteins
C) Starch
D) DNA
Answer: B) Lipids and proteins
81. The control centre of the cell is:
A) Nucleus
B) Vacuole
C) Ribosome
D) ER
Answer: A) Nucleus
82. The jelly-like substance between organelles is:
A) Cytoplasm
B) Cell wall
C) Cell sap
D) DNA
Answer: A) Cytoplasm
83. The smallest living unit is:
A) Atom
B) Cell
C) Organ
D) Tissue
Answer: B) Cell
84. Which structure controls entry and exit of materials?
A) Cell wall
B) Cell membrane
C) Nucleus
D) Ribosome
Answer: B) Cell membrane
85. Photosynthesis occurs in:
A) Chloroplast
B) Mitochondria
C) Lysosome
D) Nucleus
Answer: A) Chloroplast
86. Respiration mainly occurs in:
A) Golgi apparatus
B) Mitochondria
C) Vacuole
D) Ribosome
Answer: B) Mitochondria
87. A cell without a true nucleus is:
A) Eukaryotic
B) Prokaryotic
C) Plant cell
D) Animal cell
Answer: B) Prokaryotic
88. A large central vacuole is found in:
A) Plant cells
B) Animal cells
C) Bacteria
D) Viruses
Answer: A) Plant cells
89. The process of making food by plants is:
A) Respiration
B) Photosynthesis
C) Digestion
D) Diffusion
Answer: B) Photosynthesis
90. ATP is related to:
A) Energy
B) DNA
C) Protein
D) Cell wall
Answer: A) Energy
91. Which organelle synthesises lipids?
A) Smooth ER
B) Rough ER
C) Ribosome
D) Lysosome
Answer: A) Smooth ER
92. Which organelle synthesises proteins?
A) Ribosome
B) Vacuole
C) Chloroplast
D) Golgi body
Answer: A) Ribosome
93. The main function of nucleus is:
A) Storage of water
B) Control cell activities
C) Produce food
D) Digest waste
Answer: B) Control cell activities
94. Cell division helps in:
A) Growth and repair
B) Stopping life processes
C) Destroying cells
D) Removing DNA
Answer: A) Growth and repair
95. Meiosis produces:
A) Body cells
B) Gametes
C) Proteins
D) ATP
Answer: B) Gametes
96. The cell wall is:
A) Flexible membrane
B) Rigid outer layer
C) Genetic material
D) Energy source
Answer: B) Rigid outer layer
97. The study of inheritance is called:
A) Genetics
B) Ecology
C) Anatomy
D) Physiology
Answer: A) Genetics
98. A group of organs forms:
A) Tissue
B) Cell
C) Organ system
D) Organism
Answer: C) Organ system
99. All living organisms are made up of:
A) Atoms only
B) Cells
C) Organs only
D) Tissues only
Answer: B) Cells
100. Understanding cells helps us understand:
A) Only plants
B) Only animals
C) All living organisms
D) Only bacteria
Answer: C) All living organisms
Part 12 – One Word Answers + Important Definitions + Key Revision Sheet
A. One Word Answer Questions (100 Questions)
1. Who discovered the cell?
Answer: Robert Hooke
2. What was observed by Robert Hooke?
Answer: Cork
3. In which year were cells discovered?
Answer: 1665
4. The basic unit of life is:
Answer: Cell
5. Study of cells is called:
Answer: Cytology
6. Scientist who proposed cell theory:
Answer: Schleiden and Schwann
7. Scientist who stated that cells arise from existing cells:
Answer: Virchow
8. Outer boundary of animal cell:
Answer: Cell membrane
9. Rigid covering of plant cells:
Answer: Cell wall
10. Main component of cell wall:
Answer: Cellulose
11. Jelly-like substance inside cell:
Answer: Cytoplasm
12. Control centre of cell:
Answer: Nucleus
13. Genetic material:
Answer: DNA
14. Functional unit of heredity:
Answer: Gene
15. DNA-containing structures:
Answer: Chromosomes
16. Region containing DNA in bacteria:
Answer: Nucleoid
17. Cells without true nucleus:
Answer: Prokaryotic
18. Cells with true nucleus:
Answer: Eukaryotic
19. Powerhouse of cell:
Answer: Mitochondria
20. Energy molecule of cell:
Answer: ATP
21. Protein-making organelle:
Answer: Ribosome
22. Protein transport organelle:
Answer: Rough ER
23. Lipid synthesis organelle:
Answer: Smooth ER
24. Packaging organelle:
Answer: Golgi apparatus
25. Digestive organelle:
Answer: Lysosome
26. Photosynthetic organelle:
Answer: Chloroplast
27. Green pigment in plants:
Answer: Chlorophyll
28. Colour-producing plastid:
Answer: Chromoplast
29. Food-storing plastid:
Answer: Leucoplast
30. Storage organelle:
Answer: Vacuole
B. More One Word Questions
31. Fluid inside vacuole:
Answer: Cell sap
32. Movement of particles from high to low concentration:
Answer: Diffusion
33. Movement of water through membrane:
Answer: Osmosis
34. Cell division for growth:
Answer: Mitosis
35. Cell division for gamete formation:
Answer: Meiosis
36. Number of cells formed in mitosis:
Answer: Two
37. Number of cells formed in meiosis:
Answer: Four
38. Cell division producing identical cells:
Answer: Mitosis
39. Cell division producing variation:
Answer: Meiosis
40. Formation of tumour:
Answer: Cancer
41. Controlled cell growth:
Answer: Normal division
42. Uncontrolled cell division:
Answer: Cancer
43. Growth of cells outside body:
Answer: Cell culture
44. Energy-producing process in mitochondria:
Answer: Respiration
45. Food-making process in plants:
Answer: Photosynthesis
46. Plant food storage material:
Answer: Starch
47. Animal food storage material:
Answer: Glycogen
48. Hereditary information carrier:
Answer: DNA
49. Protective layer of plant cell:
Answer: Cell wall
50. Selectively permeable structure:
Answer: Cell membrane
C. Important Definitions for Revision
1. Cell
Definition:
The cell is the basic structural and functional unit of all living organisms.
2. Cell Theory
Definition:
The theory stating that all living organisms are made up of cells and new cells arise from existing cells.
3. Cell Membrane
Definition:
A thin selectively permeable membrane surrounding the cell that controls movement of substances.
4. Cell Wall
Definition:
A rigid outer covering present in plant cells that provides support and protection.
5. Cytoplasm
Definition:
A jelly-like substance containing cell organelles where many chemical reactions occur.
6. Nucleus
Definition:
The control centre of the cell containing genetic material.
7. DNA
Definition:
A molecule that carries hereditary information.
8. Gene
Definition:
A functional segment of DNA responsible for specific traits.
9. Chromosome
Definition:
A DNA-containing structure present in the nucleus.
10. Prokaryotic Cell
Definition:
A cell without a true nucleus and membrane-bound organelles.
11. Eukaryotic Cell
Definition:
A cell having a well-defined nucleus and membrane-bound organelles.
12. Mitochondria
Definition:
Cell organelles responsible for energy production.
13. Ribosome
Definition:
Cell organelle responsible for protein synthesis.
14. Endoplasmic Reticulum
Definition:
A membrane network involved in transport and synthesis of materials.
15. Golgi Apparatus
Definition:
An organelle responsible for modification, packaging and transport of materials.
16. Lysosome
Definition:
A digestive organelle containing enzymes that break down waste materials.
17. Chloroplast
Definition:
A plant organelle containing chlorophyll and performing photosynthesis.
18. Vacuole
Definition:
A storage structure containing cell sap.
19. Diffusion
Definition:
Movement of particles from a region of higher concentration to lower concentration.
20. Osmosis
Definition:
Movement of water through a selectively permeable membrane.
D. Important Keywords for Exam
| Topic | Keywords to Remember |
|---|---|
| Cell theory | Schleiden, Schwann, Virchow |
| Discovery | Robert Hooke, Cork, 1665 |
| Cell membrane | Selectively permeable |
| Nucleus | Control centre, DNA |
| Mitochondria | ATP, Energy |
| Ribosome | Protein synthesis |
| ER | Transport |
| Golgi body | Packaging |
| Lysosome | Digestion |
| Chloroplast | Chlorophyll, Photosynthesis |
| Vacuole | Storage, Cell sap |
| Mitosis | Growth, Repair |
| Meiosis | Gametes, Variation |
| Cancer | Uncontrolled division |
E. Most Important Exam Lines
⭐ Cell is the basic structural and functional unit of life.
⭐ All cells arise from pre-existing cells.
⭐ Mitochondria are called the powerhouse of the cell.
⭐ Ribosomes are the protein factories of cells.
⭐ The nucleus controls all activities of the cell.
⭐ Chloroplasts are the sites of photosynthesis.
⭐ Lysosomes help in digestion of waste materials.
⭐ Mitosis helps in growth and repair.
⭐ Meiosis helps in formation of gametes.
⭐ DNA carries hereditary information.
Part 13 – Assertion & Reason Questions
50 Questions with Answers
Instructions:
Choose the correct option:
A) Both Assertion (A) and Reason (R) are true, and R is the correct explanation of A.
B) Both 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.
1. Cell Discovery
Q1.
Assertion (A): Cell is called the basic unit of life.
Reason (R): All living organisms are made up of cells.
Answer: A
Explanation: Cells form the structure of all organisms and perform life activities.
Q2.
Assertion (A): Robert Hooke discovered cells in 1665.
Reason (R): He observed a thin slice of cork under a microscope.
Answer: A
Q3.
Assertion (A): Robert Hooke observed living cells.
Reason (R): He observed dead cork cells.
Answer: D
Q4.
Assertion (A): Cell theory is important in biology.
Reason (R): It explains the organisation of living organisms.
Answer: A
Q5.
Assertion (A): Schleiden studied plant cells.
Reason (R): Schwann studied animal cells.
Answer: B
2. Cell Structure
Q6.
Assertion (A): Cell membrane is selectively permeable.
Reason (R): It allows only selected substances to pass through.
Answer: A
Q7.
Assertion (A): Cell wall is present in animal cells.
Reason (R): Cell wall provides rigidity to plant cells.
Answer: D
Q8.
Assertion (A): Cytoplasm is important for cell activities.
Reason (R): Many chemical reactions occur in cytoplasm.
Answer: A
Q9.
Assertion (A): Nucleus controls cell activities.
Reason (R): Nucleus contains genetic material.
Answer: A
Q10.
Assertion (A): DNA is found inside chromosomes.
Reason (R): Chromosomes are present inside the nucleus.
Answer: B
3. Prokaryotic and Eukaryotic Cells
Q11.
Assertion (A): Bacteria are prokaryotic organisms.
Reason (R): They do not have a membrane-bound nucleus.
Answer: A
Q12.
Assertion (A): Eukaryotic cells are more complex than prokaryotic cells.
Reason (R): They contain membrane-bound organelles.
Answer: A
Q13.
Assertion (A): Prokaryotic cells have DNA.
Reason (R): Their DNA is present in the nucleoid region.
Answer: A
Q14.
Assertion (A): Human cells are prokaryotic.
Reason (R): Humans have cells with a true nucleus.
Answer: D
Q15.
Assertion (A): All cells have the same structure.
Reason (R): Cells differ according to their functions.
Answer: D
4. Cell Organelles
Q16.
Assertion (A): Mitochondria are called the powerhouse of the cell.
Reason (R): They produce ATP.
Answer: A
Q17.
Assertion (A): Ribosomes are called protein factories.
Reason (R): They help in protein synthesis.
Answer: A
Q18.
Assertion (A): Rough ER has ribosomes on its surface.
Reason (R): It helps in protein production.
Answer: A
Q19.
Assertion (A): Smooth ER helps in lipid synthesis.
Reason (R): It contains ribosomes.
Answer: C
Q20.
Assertion (A): Golgi apparatus acts as a packaging centre.
Reason (R): It modifies and packages materials.
Answer: A
5. Lysosomes, Vacuoles and Plastids
Q21.
Assertion (A): Lysosomes are called cleaning systems of cells.
Reason (R): They contain digestive enzymes.
Answer: A
Q22.
Assertion (A): Lysosomes can destroy damaged cell parts.
Reason (R): They contain digestive enzymes.
Answer: A
Q23.
Assertion (A): Vacuoles are important in plant cells.
Reason (R): They store water and maintain firmness.
Answer: A
Q24.
Assertion (A): Chloroplasts are present in animal cells.
Reason (R): Chloroplasts perform photosynthesis.
Answer: D
Q25.
Assertion (A): Chloroplasts contain chlorophyll.
Reason (R): Chlorophyll helps absorb sunlight.
Answer: A
6. Diffusion and Osmosis
Q26.
Assertion (A): Diffusion does not require energy.
Reason (R): Molecules move naturally from high concentration to low concentration.
Answer: A
Q27.
Assertion (A): Osmosis involves movement of water molecules.
Reason (R): Water moves through a selectively permeable membrane.
Answer: A
Q28.
Assertion (A): Raisins swell in pure water.
Reason (R): Water enters raisins by osmosis.
Answer: A
Q29.
Assertion (A): Cells shrink in concentrated salt solution.
Reason (R): Water moves out of cells by osmosis.
Answer: A
Q30.
Assertion (A): Diffusion occurs only in living cells.
Reason (R): Diffusion is a physical process.
Answer: D
7. Cell Division
Q31.
Assertion (A): Mitosis is important for growth.
Reason (R): It produces identical daughter cells.
Answer: A
Q32.
Assertion (A): Meiosis produces gametes.
Reason (R): It reduces chromosome number by half.
Answer: A
Q33.
Assertion (A): Mitosis maintains chromosome number.
Reason (R): Daughter cells receive the same chromosome number.
Answer: A
Q34.
Assertion (A): Meiosis produces genetic variation.
Reason (R): Daughter cells are genetically identical.
Answer: C
Q35.
Assertion (A): Cell division is necessary for repair.
Reason (R): New cells replace damaged cells.
Answer: A
8. DNA and Genetics
Q36.
Assertion (A): DNA carries hereditary information.
Reason (R): DNA contains genes.
Answer: A
Q37.
Assertion (A): Genes control traits.
Reason (R): Genes are segments of DNA.
Answer: A
Q38.
Assertion (A): Chromosomes are visible during cell division.
Reason (R): DNA becomes condensed during division.
Answer: A
Q39.
Assertion (A): DNA is present only in animals.
Reason (R): All living organisms require genetic information.
Answer: D
Q40.
Assertion (A): Nucleus is important for inheritance.
Reason (R): It contains chromosomes.
Answer: A
9. Application-Based Assertion Questions
Q41.
Assertion (A): Muscle cells contain many mitochondria.
Reason (R): Muscle cells require more energy.
Answer: A
Q42.
Assertion (A): Root cells generally lack chloroplasts.
Reason (R): Roots do not receive sunlight.
Answer: A
Q43.
Assertion (A): Plant cells do not burst easily in water.
Reason (R): They have a strong cell wall.
Answer: A
Q44.
Assertion (A): Animal cells can change shape easily.
Reason (R): They lack a rigid cell wall.
Answer: A
Q45.
Assertion (A): Cancer is related to abnormal cell division.
Reason (R): Cancer cells divide uncontrollably.
Answer: A
Q46.
Assertion (A): Cells need energy for activities.
Reason (R): Energy helps in growth, repair and transport.
Answer: A
Q47.
Assertion (A): Different cells have different shapes.
Reason (R): Cells are specialised for different functions.
Answer: A
Q48.
Assertion (A): Cell culture is useful in research.
Reason (R): It allows scientists to study cells under controlled conditions.
Answer: A
Q49.
Assertion (A): Understanding cells helps understand diseases.
Reason (R): Many diseases involve changes in cell function.
Answer: A
Q50.
Assertion (A): Organisms show different levels of organisation.
Reason (R): Cells combine to form tissues, organs and organ systems.
Answer: A
Part 14 – Diagram-Based Questions + Labelling Practice
Class 9 Exam Preparation
A. Plant Cell Diagram Questions
Diagram: Plant Cell (Important Labels)
Learn these labels:
- Cell wall
- Cell membrane
- Cytoplasm
- Nucleus
- Large vacuole
- Chloroplast
- Mitochondria
- Endoplasmic reticulum
- Golgi apparatus
- Ribosome
Q1. Identify the following parts of a plant cell:
(a) Outer rigid covering
Answer: Cell wall
(b) Green coloured organelle
Answer: Chloroplast
(c) Control centre of the cell
Answer: Nucleus
(d) Storage structure
Answer: Vacuole
(e) Site of energy production
Answer: Mitochondria
B. Animal Cell Diagram Questions
Diagram: Animal Cell (Important Labels)
Labels to remember:
- Cell membrane
- Cytoplasm
- Nucleus
- Mitochondria
- Ribosomes
- Endoplasmic reticulum
- Golgi apparatus
- Lysosomes
- Centrioles
Q2. Identify the following parts of an animal cell:
(a) Outer boundary of animal cell
Answer: Cell membrane
(b) Organelle controlling cell activities
Answer: Nucleus
(c) Organelle responsible for protein synthesis
Answer: Ribosome
(d) Organelle responsible for digestion of waste
Answer: Lysosome
(e) Organelle producing ATP
Answer: Mitochondria
C. Prokaryotic Cell Diagram Questions
Important Labels:
- Cell wall
- Cell membrane
- Cytoplasm
- Nucleoid
- Ribosomes
- Flagellum
- Capsule
Q3. Label the parts of a bacterial cell.
(a) DNA-containing region
Answer: Nucleoid
(b) Movement structure
Answer: Flagellum
(c) Protein-making structures
Answer: Ribosomes
(d) Protective outer layer
Answer: Capsule
D. Identify the Cell Type from Diagram
Q4. A diagram shows a cell with a cell wall, chloroplast and a large vacuole. Identify it.
Answer: Plant cell
Q5. A diagram shows a cell with no cell wall and no chloroplast. Identify it.
Answer: Animal cell
Q6. A diagram shows DNA without a nuclear membrane. Identify it.
Answer: Prokaryotic cell
Q7. A diagram shows a well-defined nucleus and membrane-bound organelles. Identify it.
Answer: Eukaryotic cell
E. Match the Diagram Part with Function
| Cell Part | Function |
|---|---|
| Nucleus | Controls cell activities |
| Mitochondria | Produces energy |
| Ribosome | Protein synthesis |
| Chloroplast | Photosynthesis |
| Vacuole | Storage |
| Lysosome | Digestion |
| Golgi apparatus | Packaging |
| ER | Transport |
F. Diagram-Based MCQs
1. Which structure is present only in plant cells?
A) Nucleus
B) Cell wall
C) Cytoplasm
D) Mitochondria
Answer: B) Cell wall
2. Which organelle will be labelled as the powerhouse?
A) Ribosome
B) Nucleus
C) Mitochondria
D) Vacuole
Answer: C) Mitochondria
3. The structure containing genetic material is:
A) Vacuole
B) Nucleus
C) Golgi body
D) Cell wall
Answer: B) Nucleus
4. The organelle shown with green pigment is:
A) Chloroplast
B) Lysosome
C) Ribosome
D) ER
Answer: A) Chloroplast
5. A small dot-like structure attached to ER represents:
A) Vacuole
B) Ribosome
C) Nucleus
D) Chromosome
Answer: B) Ribosome
G. Diagram-Based Short Answer Questions
1. Why does a plant cell have a cell wall?
Answer:
The cell wall provides strength, protection and maintains the shape of the plant cell.
2. Why is chloroplast present in plant cells?
Answer:
Chloroplast contains chlorophyll and performs photosynthesis.
3. Why is nucleus called the brain of the cell?
Answer:
Because it controls all activities of the cell.
4. Why are mitochondria shown as bean-shaped structures?
Answer:
Their shape allows efficient energy-producing reactions.
5. Why are ribosomes shown as small dots?
Answer:
They are tiny structures responsible for protein synthesis.
H. Draw and Label Practice (Most Important for Exams)
Students should practise drawing:
1. Plant Cell
Must label:
- Cell wall
- Cell membrane
- Nucleus
- Vacuole
- Chloroplast
- Mitochondria
2. Animal Cell
Must label:
- Cell membrane
- Nucleus
- Cytoplasm
- Mitochondria
- Ribosomes
- Golgi apparatus
3. Bacterial Cell
Must label:
- Cell wall
- Cell membrane
- Nucleoid
- Ribosomes
- Flagellum
I. Diagram-Based HOTS Questions
1. A cell has chloroplast but no cell wall. Is it a normal plant cell?
Answer:
No. A normal plant cell has both chloroplast and cell wall.
2. A cell has many mitochondria. What does this indicate?
Answer:
The cell requires a large amount of energy.
3. A cell has a large vacuole and cell wall. Which organism is likely to have this cell?
Answer:
A plant.
4. A cell has no nucleus but contains DNA. What type of cell is it?
Answer:
Prokaryotic cell.
5. A cell cannot make proteins. Which structure may be damaged?
Answer:
Ribosomes.
Part 15 – Previous Year Pattern Questions + Important Exam Questions + Answer Writing Tips
A. Very Important 1 Mark Questions (Exam Pattern)
1. Who discovered the cell?
Answer: Robert Hooke
2. Name the instrument used to observe cells.
Answer: Microscope
3. What is the basic unit of life?
Answer: Cell
4. Name the organelle known as the powerhouse of the cell.
Answer: Mitochondria
5. Name the organelle responsible for protein synthesis.
Answer: Ribosome
6. Which organelle controls all activities of the cell?
Answer: Nucleus
7. Name the green pigment present in chloroplast.
Answer: Chlorophyll
8. Name the process by which water moves through a selectively permeable membrane.
Answer: Osmosis
9. Name the process of movement of particles from higher concentration to lower concentration.
Answer: Diffusion
10. Name the cell division responsible for growth.
Answer: Mitosis
B. Important 2–3 Mark Questions
1. State the main points of cell theory.
Answer:
The main points of cell theory are:
- All living organisms are made up of one or more cells.
- Cell is the basic structural and functional unit of life.
- New cells arise from pre-existing cells.
2. Explain the functions of the nucleus.
Answer:
Functions of nucleus:
- Controls all activities of the cell.
- Stores hereditary material (DNA).
- Helps in cell division and reproduction.
3. Why are mitochondria called the powerhouse of the cell?
Answer:
Mitochondria are called the powerhouse because they produce energy in the form of ATP through cellular respiration. This energy is used for various cell activities.
4. Differentiate between plant cell and animal cell.
Answer:
| Plant Cell | Animal Cell |
|---|---|
| Cell wall present | Cell wall absent |
| Chloroplast present | Chloroplast absent |
| Large vacuole present | Small vacuoles |
5. Explain diffusion with an example.
Answer:
Diffusion is the movement of particles from a region of higher concentration to lower concentration.
Example: The smell of perfume spreading throughout a room.
6. Explain osmosis with an example.
Answer:
Osmosis is the movement of water through a selectively permeable membrane.
Example: Raisins swell when placed in water.
7. What are plastids? Name their types.
Answer:
Plastids are organelles found in plant cells.
Types:
- Chloroplast – performs photosynthesis.
- Chromoplast – gives colour to flowers and fruits.
- Leucoplast – stores food.
8. Explain the functions of Golgi apparatus.
Answer:
Functions:
- Modifies proteins and lipids.
- Packages materials.
- Helps in transport and secretion.
- Forms lysosomes.
C. Important 5 Mark Questions
1. Describe the structure of a cell.
Answer:
A cell has three main parts:
1. Cell membrane:
- Outer covering of the cell.
- Controls entry and exit of substances.
2. Cytoplasm:
- Jelly-like substance inside the cell.
- Contains cell organelles.
3. Nucleus:
- Control centre of the cell.
- Contains DNA and chromosomes.
Different organelles perform specific functions to keep the cell alive.
2. Describe important cell organelles and their functions.
Answer:
| Organelle | Function |
|---|---|
| Nucleus | Controls activities and contains DNA |
| Mitochondria | Produces energy |
| Ribosomes | Protein synthesis |
| ER | Transport of materials |
| Golgi apparatus | Packaging |
| Lysosomes | Digestion |
| Vacuoles | Storage |
| Chloroplast | Photosynthesis |
3. Explain mitosis and meiosis.
Answer:
Mitosis:
- Produces two identical daughter cells.
- Chromosome number remains unchanged.
- Helps in growth and repair.
Meiosis:
- Produces four daughter cells.
- Chromosome number becomes half.
- Helps in formation of gametes.
4. Explain prokaryotic and eukaryotic cells.
Answer:
Prokaryotic cells:
- No true nucleus.
- No membrane-bound organelles.
- Example: Bacteria.
Eukaryotic cells:
- Have true nucleus.
- Have membrane-bound organelles.
- Example: Plants and animals.
D. Frequently Asked Board-Style Questions
1. Why is the cell membrane called selectively permeable?
Answer:
Because it allows only certain substances to enter and leave the cell.
2. Why do plant cells have a cell wall?
Answer:
Plant cells have a cell wall because it provides strength, support and protection.
3. Why are lysosomes called suicidal bags?
Answer:
Because they contain digestive enzymes that can break down cell components if released.
4. Why are cells generally small in size?
Answer:
Small cells have a better surface area-to-volume ratio, allowing efficient exchange of materials.
5. Why do muscle cells have more mitochondria?
Answer:
Muscle cells require more energy for movement, so they contain more mitochondria.
E. Answer Writing Tips for Class 9 Students
For 1 Mark Questions:
✅ Write only the exact term.
Example:
Q: Powerhouse of the cell?
Answer: Mitochondria
For 2–3 Mark Questions:
Use:
- Definition
- 2–3 points
- Example (if required)
For 5 Mark Questions:
Follow this pattern:
Introduction:
Write a definition or opening statement.
Main Body:
Use:
- Headings
- Bullet points
- Tables wherever possible
Conclusion:
End with a short summary.
F. Most Expected Questions for Final Exam
⭐ Explain cell theory.
⭐ Draw and label plant cell.
⭐ Draw and label animal cell.
⭐ Differentiate between prokaryotic and eukaryotic cells.
⭐ Explain functions of mitochondria.
⭐ Explain mitosis and meiosis.
⭐ Explain diffusion and osmosis.
⭐ Write functions of cell organelles.
⭐ Explain plant cell and animal cell differences.
⭐ Explain the role of DNA and chromosomes.
G. Last Minute Revision Chart
| Topic | Remember |
|---|---|
| Cell discovery | Robert Hooke – 1665 |
| Cell theory | Schleiden, Schwann, Virchow |
| Control centre | Nucleus |
| Energy production | Mitochondria |
| Protein synthesis | Ribosome |
| Packaging | Golgi apparatus |
| Digestion | Lysosome |
| Photosynthesis | Chloroplast |
| Storage | Vacuole |
| Growth | Mitosis |
| Gamete formation | Meiosis |
| Heredity | DNA |
Part 16 – Complete Chapter Question Paper
Class 9 Level Practice Paper with Answers & Marking Scheme
Time: 2 Hours
Maximum Marks: 50
Section A – Multiple Choice Questions
(1 × 10 = 10 Marks)
1. The basic unit of life is:
A) Tissue
B) Organ
C) Cell
D) Organ system
Answer: C) Cell
2. Robert Hooke discovered cells in:
A) Blood
B) Cork
C) Leaf
D) Bacteria
Answer: B) Cork
3. The powerhouse of the cell is:
A) Nucleus
B) Ribosome
C) Mitochondria
D) Golgi apparatus
Answer: C) Mitochondria
4. Protein synthesis occurs in:
A) Ribosome
B) Vacuole
C) Lysosome
D) Chloroplast
Answer: A) Ribosome
5. The green pigment in plants is:
A) Haemoglobin
B) Chlorophyll
C) Melanin
D) Carotene
Answer: B) Chlorophyll
6. Bacteria are:
A) Eukaryotes
B) Prokaryotes
C) Multicellular organisms
D) Tissues
Answer: B) Prokaryotes
7. The control centre of the cell is:
A) Cytoplasm
B) Nucleus
C) Vacuole
D) Cell wall
Answer: B) Nucleus
8. Water movement through a selectively permeable membrane is:
A) Diffusion
B) Osmosis
C) Respiration
D) Transpiration
Answer: B) Osmosis
9. Cell division responsible for growth is:
A) Meiosis
B) Mitosis
C) Fertilisation
D) Mutation
Answer: B) Mitosis
10. DNA is present inside:
A) Vacuoles
B) Chromosomes
C) Ribosomes
D) Lysosomes
Answer: B) Chromosomes
Section B – Fill in the Blanks
(1 × 10 = 10 Marks)
1. The study of cells is called __________.
Answer: Cytology
2. The cell was discovered by __________.
Answer: Robert Hooke
3. The cell membrane is __________ permeable.
Answer: Selectively
4. The jelly-like substance inside a cell is called __________.
Answer: Cytoplasm
5. Mitochondria produce energy in the form of __________.
Answer: ATP
6. The organelle responsible for photosynthesis is __________.
Answer: Chloroplast
7. The genetic material of a cell is __________.
Answer: DNA
8. Plant cell walls are made of __________.
Answer: Cellulose
9. The division that produces gametes is called __________.
Answer: Meiosis
10. Lysosomes contain __________ enzymes.
Answer: Digestive
Section C – Very Short Answer Questions
(2 × 5 = 10 Marks)
1. Define a cell.
Answer:
A cell is the basic structural and functional unit of life.
2. Name two types of cells based on nucleus structure.
Answer:
- Prokaryotic cells
- Eukaryotic cells
3. Write two functions of mitochondria.
Answer:
- Produces ATP energy.
- Helps in cellular respiration.
4. What is osmosis?
Answer:
Osmosis is the movement of water through a selectively permeable membrane from higher water concentration to lower water concentration.
5. Give two differences between plant and animal cells.
Answer:
| Plant Cell | Animal Cell |
|---|---|
| Cell wall present | Cell wall absent |
| Chloroplast present | Chloroplast absent |
Section D – Short Answer Questions
(3 × 5 = 15 Marks)
1. Explain cell theory.
Answer:
Cell theory states that:
- All living organisms are made up of cells.
- Cell is the basic unit of life.
- New cells arise from existing cells.
2. Explain the functions of nucleus.
Answer:
Functions of nucleus:
- Controls all activities of the cell.
- Contains DNA.
- Helps in reproduction and cell division.
3. Describe the functions of the following:
(a) Ribosome
Answer: Helps in protein synthesis.
(b) Golgi apparatus
Answer: Packages and transports materials.
(c) Lysosome
Answer: Digests waste materials.
4. Differentiate between prokaryotic and eukaryotic cells.
Answer:
| Prokaryotic Cell | Eukaryotic Cell |
|---|---|
| No true nucleus | True nucleus present |
| No membrane-bound organelles | Organelles present |
| Example: Bacteria | Example: Plants and animals |
5. Explain diffusion with an example.
Answer:
Diffusion is the movement of particles from a region of higher concentration to lower concentration.
Example: Spread of perfume smell in a room.
Section E – Long Answer Questions
(5 × 1 = 5 Marks)
1. Describe the structure and functions of cell organelles.
Answer:
Cells contain different organelles that perform specific functions:
Nucleus:
- Controls cell activities.
- Contains DNA.
Mitochondria:
- Produce energy.
- Known as powerhouse of the cell.
Ribosomes:
- Make proteins.
Endoplasmic Reticulum:
- Helps in transport and synthesis.
Golgi Apparatus:
- Modifies and packages substances.
Lysosomes:
- Digest waste materials.
Chloroplast:
- Performs photosynthesis in plants.
Vacuoles:
- Store materials.
Section F – Diagram Question
(5 Marks)
Draw and label a plant cell.
Important labels:
- Cell wall
- Cell membrane
- Cytoplasm
- Nucleus
- Chloroplast
- Vacuole
- Mitochondria
Marking Scheme
| Section | Marks |
|---|---|
| MCQ | 10 |
| Fill in the blanks | 10 |
| Very short answers | 10 |
| Short answers | 15 |
| Long answer | 5 |
| Diagram | 5 |
| Total | 55 |
Part 17 – 100 Most Important Questions for Final Revision
Class 9 Exam Expected Questions with Answers
A. Very Short Answer Questions (1 Mark)
1. What is a cell?
Answer:
A cell is the basic structural and functional unit of life.
2. Who discovered the cell?
Answer:
Robert Hooke
3. What did Robert Hooke observe?
Answer:
Cork cells
4. Which instrument is used to observe cells?
Answer:
Microscope
5. Name the scientist who proposed cell theory.
Answer:
Schleiden and Schwann
6. Who stated that new cells arise from existing cells?
Answer:
Virchow
7. Name the outer covering of animal cells.
Answer:
Cell membrane
8. Name the rigid covering of plant cells.
Answer:
Cell wall
9. What is the main component of the plant cell wall?
Answer:
Cellulose
10. Name the jelly-like substance inside cells.
Answer:
Cytoplasm
11. Which organelle controls cell activities?
Answer:
Nucleus
12. What is the genetic material of the cell?
Answer:
DNA
13. Where are genes located?
Answer:
Chromosomes
14. Name the energy-producing organelle.
Answer:
Mitochondria
15. Why are mitochondria called the powerhouse of the cell?
Answer:
Because they produce ATP energy.
16. Name the organelle responsible for protein synthesis.
Answer:
Ribosome
17. Name the packaging organelle.
Answer:
Golgi apparatus
18. Name the digestive organelle.
Answer:
Lysosome
19. Name the photosynthetic organelle.
Answer:
Chloroplast
20. Name the green pigment in plants.
Answer:
Chlorophyll
B. Short Answer Questions (2–3 Marks)
21. Write the three main statements of cell theory.
Answer:
- All living organisms are made up of cells.
- Cell is the basic unit of life.
- New cells arise from existing cells.
22. Explain the role of the nucleus.
Answer:
The nucleus:
- Controls all cell activities.
- Contains DNA.
- Helps in reproduction and cell division.
23. What is the function of the cell membrane?
Answer:
The cell membrane:
- Forms the boundary of the cell.
- Controls movement of substances in and out.
- Maintains internal conditions of the cell.
24. Why is cytoplasm important?
Answer:
Cytoplasm:
- Holds cell organelles.
- Provides a place for chemical reactions.
- Helps in movement of materials inside the cell.
25. Write functions of mitochondria.
Answer:
- Produces ATP energy.
- Performs cellular respiration.
- Supplies energy for cell activities.
26. Write functions of ribosomes.
Answer:
- Produce proteins.
- Help in cell growth and repair.
27. Write functions of Golgi apparatus.
Answer:
- Modifies proteins and lipids.
- Packages materials.
- Helps in secretion.
28. Write functions of lysosomes.
Answer:
- Digest waste materials.
- Remove damaged cell parts.
- Help maintain cell cleanliness.
29. What are plastids?
Answer:
Plastids are plant cell organelles involved in food preparation, colour and storage.
Types:
- Chloroplast
- Chromoplast
- Leucoplast
30. Explain diffusion.
Answer:
Diffusion is the movement of particles from a region of higher concentration to lower concentration.
Example: Smell of perfume spreading in air.
C. Difference-Based Questions
31. Differentiate between plant and animal cells.
Answer:
| Plant Cell | Animal Cell |
|---|---|
| Cell wall present | Cell wall absent |
| Chloroplast present | Chloroplast absent |
| Large vacuole present | Small vacuoles |
| Fixed shape | Flexible shape |
32. Differentiate between prokaryotic and eukaryotic cells.
Answer:
| Prokaryotic Cell | Eukaryotic Cell |
|---|---|
| No true nucleus | True nucleus present |
| No membrane-bound organelles | Membrane-bound organelles present |
| Example: Bacteria | Example: Plants and animals |
33. Differentiate between diffusion and osmosis.
Answer:
| Diffusion | Osmosis |
|---|---|
| Movement of particles | Movement of water |
| No membrane required | Requires selectively permeable membrane |
| Occurs in gases and liquids | Occurs mainly in cells |
34. Differentiate between mitosis and meiosis.
Answer:
| Mitosis | Meiosis |
|---|---|
| Produces two cells | Produces four cells |
| Growth and repair | Gamete formation |
| Chromosome number remains same | Chromosome number becomes half |
D. Long Answer Questions (5 Marks)
35. Describe the structure of a cell.
Answer:
A cell consists of:
Cell membrane:
- Outer boundary.
- Controls entry and exit of substances.
Cytoplasm:
- Jelly-like material.
- Contains organelles.
Nucleus:
- Controls cell activities.
- Contains DNA.
Cell organelles perform different functions to keep the cell alive.
36. Explain important cell organelles and their functions.
Answer:
| Organelle | Function |
|---|---|
| Nucleus | Controls activities |
| Mitochondria | Energy production |
| Ribosomes | Protein synthesis |
| ER | Transport |
| Golgi apparatus | Packaging |
| Lysosomes | Digestion |
| Chloroplast | Photosynthesis |
| Vacuole | Storage |
37. Explain osmosis with an example.
Answer:
Osmosis is the movement of water through a selectively permeable membrane from higher water concentration to lower water concentration.
Example:
- Raisins swell when placed in water because water enters them through osmosis.
38. Explain types of cell division.
Answer:
Mitosis:
- Produces identical daughter cells.
- Helps in growth and repair.
Meiosis:
- Produces gametes.
- Reduces chromosome number by half.
39. Explain the importance of DNA.
Answer:
DNA:
- Stores genetic information.
- Controls inherited characteristics.
- Helps in making proteins.
- Transfers traits from parents to offspring.
E. Higher Thinking Questions
40. Why are cells small in size?
Answer:
Small cells have a greater surface area compared to volume, making exchange of materials easier.
41. Why do muscle cells contain many mitochondria?
Answer:
Because muscles require large amounts of energy.
42. Why do plant cells not burst in water?
Answer:
Because the cell wall provides strength and prevents bursting.
43. Why are chloroplasts absent in animal cells?
Answer:
Animals do not perform photosynthesis.
44. Why is nucleus called the brain of the cell?
Answer:
Because it controls all activities of the cell.
45. Why are lysosomes called suicidal bags?
Answer:
Because their enzymes can digest cell components when released.
46. Why is meiosis important?
Answer:
It forms gametes and maintains chromosome number in organisms.
47. Why is mitosis important?
Answer:
It helps in growth, repair and replacement of cells.
48. Why do cells need energy?
Answer:
Energy is required for growth, repair, movement and other life processes.
49. Why is DNA called hereditary material?
Answer:
Because it carries information passed from parents to offspring.
50. Why is studying cells important?
Answer:
Because cells form the basis of all living organisms and help us understand life processes.
Part 17B – 100 Most Important Questions for Final Revision
Questions 51–100 with Answers
F. Important Conceptual Questions
51. Why are cells called the building blocks of life?
Answer:
Cells are called building blocks because all living organisms are made up of cells, and cells form tissues, organs and organ systems.
52. Why do multicellular organisms have specialised cells?
Answer:
Different cells perform different functions efficiently, so organisms have specialised cells.
53. Why can Amoeba survive as a single cell?
Answer:
Amoeba performs all necessary life processes like nutrition, respiration and reproduction within one cell.
54. Why do large organisms need many cells?
Answer:
Many cells allow division of labour and efficient performance of different functions.
55. Why is the cell membrane important for survival?
Answer:
It controls the movement of substances and maintains the internal environment of the cell.
56. What happens if the nucleus is removed from a cell?
Answer:
The cell loses control over its activities and cannot survive for long.
57. Why are organelles important?
Answer:
Organelles perform specific functions required for the survival and proper functioning of cells.
58. Why are mitochondria called semi-autonomous organelles?
Answer:
Because they contain their own DNA and can make some proteins.
59. Why are chloroplasts called semi-autonomous?
Answer:
Because they contain their own DNA and ribosomes.
60. Why is ATP important for cells?
Answer:
ATP provides energy required for various cellular activities.
G. Application-Based Questions
61. A cell has no cell wall but contains a nucleus. Identify the cell.
Answer:
Animal cell.
62. A cell has a cell wall, chloroplast and a large vacuole. Identify it.
Answer:
Plant cell.
63. A cell has DNA but no nuclear membrane. Identify it.
Answer:
Prokaryotic cell.
64. A cell contains many ribosomes. What function will be high?
Answer:
Protein synthesis.
65. A cell contains many mitochondria. What does it indicate?
Answer:
The cell requires more energy.
66. A plant cell loses water and becomes soft. Which process occurred?
Answer:
Osmosis (water loss).
67. A raisin placed in water becomes swollen. Why?
Answer:
Water enters the raisin through osmosis.
68. A cell placed in concentrated salt solution shrinks. Why?
Answer:
Water moves out of the cell by osmosis.
69. Why does perfume smell spread throughout a room?
Answer:
Due to diffusion of perfume molecules.
70. Why are leaves green?
Answer:
Because chloroplasts contain chlorophyll.
H. Important Reasoning Questions
71. Why do plant cells have a fixed shape?
Answer:
Because they have a rigid cell wall.
72. Why do animal cells have irregular shapes?
Answer:
Because they lack a rigid cell wall.
73. Why is the cell wall absent in animal cells?
Answer:
Animals need flexible cells for movement and different functions.
74. Why is the vacuole larger in plant cells?
Answer:
It stores water and maintains the firmness of plant cells.
75. Why are ribosomes found in all living cells?
Answer:
Because all cells need proteins for growth and survival.
76. Why is ER called a transport system of the cell?
Answer:
Because it transports materials within the cell.
77. Why does Golgi apparatus modify proteins?
Answer:
To prepare proteins for transport and secretion.
78. Why are lysosomes necessary for cells?
Answer:
They remove waste materials and damaged cell parts.
79. Why is chloroplast important for plants?
Answer:
It helps plants prepare food through photosynthesis.
80. Why is photosynthesis important for life?
Answer:
It produces food and releases oxygen.
I. Cell Division Questions
81. Why does mitosis produce identical cells?
Answer:
Because the daughter cells receive the same genetic material.
82. Why does meiosis reduce chromosome number?
Answer:
To produce gametes with half the chromosome number.
83. Where does meiosis occur?
Answer:
In reproductive organs.
84. Where does mitosis occur?
Answer:
In body cells.
85. How does mitosis help in wound healing?
Answer:
It produces new cells that replace damaged cells.
86. Why is meiosis important for sexual reproduction?
Answer:
It produces gametes needed for reproduction.
87. What happens if cell division stops?
Answer:
Growth, repair and reproduction will stop.
88. Why is uncontrolled cell division harmful?
Answer:
It may cause formation of tumours and cancer.
89. Which cell division helps maintain chromosome number?
Answer:
Mitosis.
90. Which cell division creates variation?
Answer:
Meiosis.
J. Final Revision Questions
91. Name the three main parts of a cell.
Answer:
- Cell membrane
- Cytoplasm
- Nucleus
92. Name two examples of prokaryotic organisms.
Answer:
Bacteria and cyanobacteria.
93. Name two examples of eukaryotic organisms.
Answer:
Plants and animals.
94. What is the function of chromosomes?
Answer:
They carry hereditary information.
95. What are genes?
Answer:
Genes are functional units of DNA that control traits.
96. What is cell culture?
Answer:
Cell culture is the growth of cells outside the organism under controlled conditions.
97. What causes cancer?
Answer:
Uncontrolled and abnormal cell division.
98. Why are microscopes important in biology?
Answer:
They help observe tiny structures like cells and organelles.
99. How do cells maintain life?
Answer:
Cells perform nutrition, respiration, transport, growth and reproduction.
100. Write the importance of studying cells.
Answer:
Studying cells helps us understand the structure, functions, growth and diseases of living organisms.
Q/A
1.
Answer:
Robert Hooke discovered cells in 1665. He observed a thin slice of cork under a microscope and saw many small box-like structures. He called these structures “cells” because they looked like small rooms.
2.
Answer:
The cell is called the structural and functional unit of life because:
- All living organisms are made up of one or more cells.
- Cells combine to form tissues, organs and organ systems.
- All basic life processes such as respiration, nutrition, growth and reproduction occur inside cells.
3.
Answer:
Substances move across the cell membrane through different processes:
- Carbon dioxide and oxygen move by diffusion from a region of higher concentration to a region of lower concentration.
- Water moves by osmosis through a selectively permeable membrane.
4.
Answer:
The plasma membrane is called selectively permeable because it allows only certain substances to enter and leave the cell while restricting others. This helps maintain the proper internal conditions of the cell.
5. Fill in the blanks.
(a) The fluid mosaic model was proposed by __________.
Answer: Singer and Nicolson
(b) The movement of water through a selectively permeable membrane is called __________.
Answer: Osmosis
(c) The powerhouse of the cell is __________.
Answer: Mitochondria
(d) The control centre of the cell is __________.
Answer: Nucleus
6.
Answer:
The two organelles are:
- Mitochondria
- Chloroplasts
These are called semi-autonomous organelles because they contain their own genetic material and ribosomes.
7.
Answer:
If the organisation of a cell is damaged:
- Cell organelles cannot function properly.
- Important life processes are disturbed.
- The cell may stop working and eventually die.
- The overall health of the organism may be affected.
8.
Answer:
Lysosomes contain powerful digestive enzymes. If a cell becomes damaged, these enzymes may break down the cell components. Therefore, lysosomes are called the “suicide bags” of the cell.
9.
Answer:
Proteins are synthesised by ribosomes present in the cytoplasm or attached to the rough endoplasmic reticulum.
10.
| Plant Cell | Animal Cell |
|---|---|
| Cell wall is present | Cell wall is absent |
| Chloroplasts are present | Chloroplasts are absent |
| Large central vacuole is present | Small vacuoles may be present |
| Usually fixed shape | Usually irregular shape |
| Food is prepared by photosynthesis | Food is obtained from external sources |
11.
| Prokaryotic Cell | Eukaryotic Cell |
|---|---|
| No true nucleus | True nucleus present |
| Membrane-bound organelles absent | Membrane-bound organelles present |
| Smaller and simpler structure | Larger and more complex structure |
| DNA lies in nucleoid region | DNA is present inside nucleus |
| Example: Bacteria | Example: Plants and animals |
12.
(a) Mitochondria
Functions:
- Produce energy in the form of ATP.
- Carry out cellular respiration.
- Supply energy required for cell activities.
(b) Ribosomes
Functions:
- Help in protein synthesis.
- Support growth and repair of cells.
(c) Golgi Apparatus
Functions:
- Modifies proteins and lipids.
- Packages and transports materials.
- Helps in the formation of lysosomes.
(d) Endoplasmic Reticulum
Functions:
- Transports materials inside the cell.
- Rough ER helps in protein synthesis.
- Smooth ER helps in lipid synthesis.
(e) Lysosomes
Functions:
- Digest waste materials.
- Remove damaged cell parts.
- Help keep the cell clean.
13.
Answer:
Plant cells are more rigid because they have a strong cell wall made of cellulose. The cell wall provides support, protection and maintains the shape of the cell.
Animal cells do not have a cell wall, so they are more flexible.
14.
Answer:
The nucleus is important because:
- It controls all activities of the cell.
- It contains DNA and chromosomes.
- It regulates cell growth and reproduction.
- It carries hereditary information from parents to offspring.
15.
Diffusion
Definition:
Diffusion is the movement of particles from a region of higher concentration to a region of lower concentration.
Example:
The smell of perfume spreads throughout a room due to diffusion.
Osmosis
Definition:
Osmosis is the movement of water through a selectively permeable membrane from a region of higher water concentration to lower water concentration.
Example:
Raisins swell when placed in water because water enters them through osmosis.
Disclaimer:
These notes are independently prepared for educational purposes. They are simplified, original study materials created to help Class 9 students understand and revise the chapter. They are not a replacement for the official textbook. Students should refer to their prescribed textbook and class notes for complete learning.