🧬 The Fundamental Unit of Life – Class 9 Science MCQs

Section 2: Plant Cell, Animal Cell & Organelles (Part I) (Q26–Q50)

Q26. The outermost covering of an animal cell is:

A. Cell wall
B. Plasma membrane
C. Nucleus
D. Cytoplasm

✅ Correct Answer: B. Plasma membrane

Explanation:

• A. Cell wall → Absent in animals.
• B. Plasma membrane → Correct, selectively permeable layer.
• C. Nucleus → Present inside, not outermost.
• D. Cytoplasm → Inside the membrane.

Q27. The cell wall of plants is made up of:

A. Proteins
B. Cellulose
C. Fats
D. Lipids

✅ Correct Answer: B. Cellulose

Explanation:

• A. Proteins → Wrong.
• B. Cellulose → Correct, gives rigidity.
• C & D. Fats/Lipids → Not cell wall component.

Q28. Function of plasma membrane is:

A. Protein synthesis
B. Control entry & exit of substances
C. Provide rigidity
D. Energy production

✅ Correct Answer: B. Control entry & exit of substances

Explanation:

• A. Protein synthesis → Ribosomes.
• B. Correct, plasma membrane is selectively permeable.
• C. Rigidity → Cell wall.
• D. Energy production → Mitochondria.

Q29. Diffusion is:

A. Movement of water from high to low concentration
B. Movement of particles from high to low concentration
C. Movement of water through membrane
D. Active transport

✅ Correct Answer: B. Movement of particles from high to low concentration

Explanation:

• A. Water movement = Osmosis.
• B. Correct, diffusion of gases or solutes.
• C. Osmosis is specific to water.
• D. Active transport requires energy.

Q30. Osmosis is:

A. Diffusion of gases
B. Diffusion of water through a semi-permeable membrane
C. Movement of salts through membrane
D. Active transport of ions

✅ Correct Answer: B. Diffusion of water through a semi-permeable membrane

Explanation:

• A. Wrong, gases don’t need membrane.
• B. Correct.
• C. Not general definition.
• D. Osmosis is passive, not active.

Q31. When a cell is placed in hypotonic solution, it:

A. Shrinks
B. Swells
C. No change
D. Bursts always

✅ Correct Answer: B. Swells

Explanation:

• A. Shrinks → Hypertonic solution.
• B. Correct, water enters cell.
• C. Isotonic = no change.
• D. May burst, but not always.

Q32. When a cell is placed in hypertonic solution, it undergoes:

A. Endocytosis
B. Exocytosis
C. Plasmolysis
D. Cytolysis

✅ Correct Answer: C. Plasmolysis

Explanation:

• A. Endocytosis → Cell engulfs.
• B. Exocytosis → Cell expels.
• C. Correct, water leaves, cytoplasm shrinks.
• D. Cytolysis → Bursting.

Q33. Which organelle is called “suicidal bag” of the cell?

A. Ribosome
B. Lysosome
C. Mitochondria
D. Golgi body

✅ Correct Answer: B. Lysosome

Explanation:

• A. Ribosome → Protein synthesis.
• B. Correct, lysosome contains digestive enzymes.
• C. Mitochondria → Powerhouse.
• D. Golgi → Packaging.

Q34. Which organelle is known as the “powerhouse of cell”?

A. Ribosome
B. Lysosome
C. Golgi body
D. Mitochondria

✅ Correct Answer: D. Mitochondria

Explanation:

• A. Ribosome → Protein synthesis.
• B. Lysosome → Digestion.
• C. Golgi → Packaging.
• D. Mitochondria → Correct, ATP production.

Q35. The site of protein synthesis is:

A. Lysosome
B. Ribosome
C. Mitochondria
D. Golgi apparatus

✅ Correct Answer: B. Ribosome

Explanation:

• A. Lysosome → Digestion.
• B. Correct, ribosomes synthesize proteins.
• C. Mitochondria → Respiration.
• D. Golgi → Packaging.

Q36. Which organelle is responsible for packaging and secretion?

A. Ribosome
B. Golgi body
C. Lysosome
D. Plastid

✅ Correct Answer: B. Golgi body

Explanation:

• A. Protein synthesis only.
• B. Correct, modifies, packages, and secretes.
• C. Lysosome → Digestion.
• D. Plastids → Photosynthesis/storage.

Q37. Which organelle forms lysosomes?

A. Ribosome
B. Mitochondria
C. Golgi body
D. Nucleus

✅ Correct Answer: C. Golgi body

Explanation:

• A. Wrong.
• B. Wrong.
• C. Correct, Golgi forms vesicles → lysosomes.
• D. Nucleus → Genetic control, not lysosome formation.

Q38. Which organelle is responsible for intracellular digestion?

A. Ribosome
B. Lysosome
C. Mitochondria
D. Vacuole

✅ Correct Answer: B. Lysosome

Explanation:

• A. Protein synthesis.
• B. Correct, lysosomes contain hydrolytic enzymes.
• C. Respiration.
• D. Vacuole → Storage.

Q39. Which organelle controls all cell activities?

A. Nucleus
B. Ribosome
C. Mitochondria
D. Golgi body

✅ Correct Answer: A. Nucleus

Explanation:

• A. Correct, nucleus = control center with DNA.
• B. Ribosome → Only proteins.
• C. Respiration.
• D. Packaging.

Q40. The fluid inside nucleus is called:

A. Cytoplasm
B. Nucleoplasm
C. Protoplasm
D. Chromatin

✅ Correct Answer: B. Nucleoplasm

Explanation:

• A. Cytoplasm → Outside nucleus.
• B. Correct, nuclear sap.
• C. Protoplasm = cytoplasm + nucleus.
• D. Chromatin = DNA + proteins.

Q41. The thread-like structures in nucleus are:

A. Chromosomes
B. Ribosomes
C. Microtubules
D. Vesicles

✅ Correct Answer: A. Chromosomes

Explanation:

• A. Correct, carriers of genetic material.
• B. Ribosomes in cytoplasm.
• C. Microtubules = cytoskeleton.
• D. Vesicles = transport.

Q42. DNA is found in:

A. Cytoplasm only
B. Nucleus only
C. Nucleus, mitochondria, chloroplast
D. Only cell wall

✅ Correct Answer: C. Nucleus, mitochondria, chloroplast

Explanation:

• A. Prokaryotes → Nucleoid, not only cytoplasm.
• B. Not just nucleus.
• C. Correct, DNA in nucleus & semi-autonomous organelles.
• D. Cell wall has no DNA.

Q43. The green plastids in plant cells are called:

A. Chloroplasts
B. Chromoplasts
C. Leucoplasts
D. Plastids

✅ Correct Answer: A. Chloroplasts

Explanation:

• A. Correct, chloroplasts contain chlorophyll.
• B. Chromoplasts → Colored (red, yellow).
• C. Leucoplasts → Storage plastids.
• D. General term.

Q44. Which pigment is found in chloroplast?

A. Carotene
B. Chlorophyll
C. Anthocyanin
D. Hemoglobin

✅ Correct Answer: B. Chlorophyll

Explanation:

• A. Carotene → Accessory pigment.
• B. Correct, chlorophyll absorbs sunlight.
• C. Anthocyanin → Flower pigments.
• D. Hemoglobin → Blood protein.

Q45. Which plastid is colorless and stores starch?

A. Chloroplast
B. Chromoplast
C. Leucoplast
D. Plastid

✅ Correct Answer: C. Leucoplast

Explanation:

• A. Chloroplast → Green.
• B. Chromoplast → Colored.
• C. Correct, storage plastids (starch, oil, protein).
• D. General term.

Q46. Which organelle is called the “kitchen of the cell”?

A. Ribosome
B. Chloroplast
C. Mitochondria
D. Golgi body

✅ Correct Answer: B. Chloroplast

Explanation:

• A. Protein synthesis.
• B. Correct, photosynthesis.
• C. Respiration.
• D. Packaging.

Q47. Vacuoles are larger in:

A. Animal cells
B. Plant cells
C. Bacteria
D. Fungi

✅ Correct Answer: B. Plant cells

Explanation:

• A. Small in animals.
• B. Correct, large central vacuole.
• C. Absent in prokaryotes.
• D. Not large.

Q48. Function of vacuole in plant cells is:

A. Storage & turgidity
B. Respiration
C. Photosynthesis
D. Protein synthesis

✅ Correct Answer: A. Storage & turgidity

Explanation:

• A. Correct, stores water, salts & maintains turgor.
• B. Mitochondria.
• C. Chloroplast.
• D. Ribosomes.

Q49. Which of these organelles is absent in animal cells?

A. Nucleus
B. Mitochondria
C. Chloroplast
D. Ribosome

✅ Correct Answer: C. Chloroplast

Explanation:

• A. Nucleus present.
• B. Mitochondria present.
• C. Correct, chloroplasts absent in animals.
• D. Ribosomes present.

Q50. Which organelle gives structural support to cell shape?

A. Lysosome
B. Cytoskeleton
C. Golgi body
D. Ribosome

✅ Correct Answer: B. Cytoskeleton

Explanation:

• A. Digestion.
• B. Correct, microtubules & filaments support structure.
• C. Packaging.
• D. Protein synthesis.

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