🧬 The Fundamental Unit of Life – Class 9 Science MCQs

Section 3: Organelles Part II & Plant vs Animal Cells (Q51–Q75)

Q51. The “control center” of the cell is:

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

✅ Correct Answer: B. Nucleus

Explanation:

• A. Ribosome → Protein synthesis.
• B. Correct, nucleus controls cell functions & stores DNA.
• C. Mitochondria → Energy production.
• D. Golgi body → Packaging.

Q52. Which part of nucleus is responsible for ribosome formation?

A. Nuclear membrane
B. Nucleolus
C. Nucleoplasm
D. Chromatin

✅ Correct Answer: B. Nucleolus

Explanation:

• A. Nuclear membrane → Protective layer.
• B. Correct, nucleolus synthesizes rRNA & ribosome subunits.
• C. Nucleoplasm → Nuclear sap.
• D. Chromatin → DNA + proteins.

Q53. Chromosomes are made of:

A. DNA only
B. RNA only
C. DNA + proteins
D. Lipids

✅ Correct Answer: C. DNA + proteins

Explanation:

• A. DNA only → Incomplete.
• B. RNA → Wrong, not in chromosomes.
• C. Correct, DNA + histone proteins.
• D. Lipids → Not part of chromosomes.

Q54. Which organelle is called “protein factory”?

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

✅ Correct Answer: A. Ribosome

Explanation:

• A. Correct, ribosomes make proteins.
• B. Golgi → Packaging.
• C. Nucleolus → Ribosome synthesis, not proteins.
• D. Lysosome → Digestion.

Q55. Which organelle is absent in prokaryotes but present in eukaryotes?

A. Ribosome
B. Plasma membrane
C. Mitochondria
D. Cytoplasm

✅ Correct Answer: C. Mitochondria

Explanation:

• A. Ribosomes present in both.
• B. Plasma membrane present in both.
• C. Correct, mitochondria only in eukaryotes.
• D. Cytoplasm present in both.

Q56. Which organelle is responsible for photosynthesis?

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

✅ Correct Answer: A. Chloroplast

Explanation:

• A. Correct, contains chlorophyll.
• B. Chromoplast → Colored plastids, no photosynthesis.
• C. Respiration.
• D. Protein synthesis.

Q57. Which pigment in chloroplast traps sunlight?

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

✅ Correct Answer: C. Chlorophyll

Explanation:

• A. Xanthophyll & B. Carotene → Accessory pigments.
• C. Correct, chlorophyll absorbs light energy.
• D. Anthocyanin → Gives flower colors.

Q58. The organelle that digests worn-out cell parts is:

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

✅ Correct Answer: C. Lysosome

Explanation:

• A. Golgi → Packaging.
• B. Mitochondria → Energy.
• C. Correct, lysosomes digest cell debris.
• D. Ribosomes → Proteins.

Q59. Which organelle is double-membrane bound?

A. Mitochondria
B. Plastids
C. Nucleus
D. All of these

✅ Correct Answer: D. All of these

Explanation:

• A. Mitochondria → Yes.
• B. Plastids → Yes.
• C. Nucleus → Yes.
• D. Correct, all are double-membrane bound.

Q60. Which of these is single-membrane bound?

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

✅ Correct Answer: B. Lysosome

Explanation:

• A. Ribosomes → Non-membrane bound.
• B. Correct, lysosome = single membrane vesicle.
• C & D → Double-membrane.

Q61. Which organelle is called “cellular respiration site”?

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

✅ Correct Answer: B. Mitochondria

Explanation:

• A. Proteins.
• B. Correct, mitochondria perform aerobic respiration.
• C. Photosynthesis.
• D. Packaging.

Q62. Which of these is present only in plant cells?

A. Chloroplast
B. Cell wall
C. Large central vacuole
D. All of these

✅ Correct Answer: D. All of these

Explanation:

• A. Chloroplast → Plant specific.
• B. Cell wall → Plant specific.
• C. Large vacuole → Plant specific.
• D. All correct.

Q63. Which organelle is absent in animal cells?

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

✅ Correct Answer: C. Chloroplast

Explanation:

• A. Present.
• B. Present.
• C. Correct, chloroplast absent in animals.
• D. Present.

Q64. Which gives mechanical support & shape to plant cells?

A. Mitochondria
B. Cell wall
C. Ribosome
D. Nucleus

✅ Correct Answer: B. Cell wall

Explanation:

• A. Energy.
• B. Correct, rigid cellulose wall provides shape & support.
• C. Proteins.
• D. Genetic control, not shape.

Q65. Which of the following is not an organelle with its own DNA?

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

✅ Correct Answer: D. Ribosome

Explanation:

• A. Chloroplast → Own DNA.
• B. Mitochondria → Own DNA.
• C. Nucleus → Contains DNA.
• D. Correct, ribosomes are RNA+protein, no DNA.

Q66. Plant cells are different from animal cells because:

A. Have chloroplasts
B. Have large vacuoles
C. Have cell wall
D. All of these

✅ Correct Answer: D. All of these

Explanation:

• All three differences valid.

Q67. Which organelle performs detoxification of drugs in liver cells?

A. Rough ER
B. Smooth ER
C. Golgi body
D. Lysosome

✅ Correct Answer: B. Smooth ER

Explanation:

• A. RER → Proteins.
• B. Correct, SER detoxifies & makes lipids.
• C. Packaging.
• D. Digestion.

Q68. Rough ER is rough because:

A. Made of proteins
B. Covered with ribosomes
C. Has enzymes
D. Has lysosomes

✅ Correct Answer: B. Covered with ribosomes

Explanation:

• A. Not reason.
• B. Correct, ribosomes attach to ER → rough appearance.
• C. Enzymes don’t make roughness.
• D. Lysosomes not on ER.

Q69. Which cell organelle is the transport system of the cell?

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

✅ Correct Answer: A. ER

Explanation:

• A. Correct, ER transports proteins & lipids.
• B. Golgi → Packaging, not main transport.
• C. Ribosome → Protein synthesis.
• D. Nucleus → Control.

Q70. Which ER synthesizes proteins?

A. Smooth ER
B. Rough ER
C. Both
D. None

✅ Correct Answer: B. Rough ER

Explanation:

• A. SER → Lipids.
• B. RER → Ribosomes attached → protein synthesis.
• C. Not both.
• D. Wrong.

Q71. Which ER synthesizes lipids?

A. Rough ER
B. Smooth ER
C. Golgi body
D. Ribosome

✅ Correct Answer: B. Smooth ER

Explanation:

• A. RER → Proteins.
• B. Correct, SER makes lipids & detoxifies.
• C. Golgi → Packaging.
• D. Ribosomes → Proteins.

Q72. Which organelle acts as a storage sac for food & waste?

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

✅ Correct Answer: C. Vacuole

Explanation:

• A. Ribosome → Proteins.
• B. Lysosome → Digestion.
• C. Correct, vacuole stores water, salts, food, waste.
• D. Packaging.

Q73. In animal cells, vacuoles are:

A. Large & central
B. Small & temporary
C. Absent
D. Filled with chlorophyll

✅ Correct Answer: B. Small & temporary

Explanation:

• A. Large central vacuole → Plant cells.
• B. Correct.
• C. Not absent, just small.
• D. Chlorophyll in chloroplasts, not vacuole.

Q74. Cell wall is mainly composed of:

A. Starch
B. Cellulose
C. Protein
D. Chitin

✅ Correct Answer: B. Cellulose

Explanation:

• A. Starch → Storage.
• B. Correct, cellulose = structural polysaccharide.
• C. Proteins not main.
• D. Chitin = fungal cell wall.

Q75. Which organelle is called “traffic police” of the cell for packaging & dispatching?

A. Ribosome
B. Golgi apparatus
C. ER
D. Vacuole

✅ Correct Answer: B. Golgi apparatus

Explanation:

• A. Ribosome → Proteins only.
• B. Correct, Golgi modifies, packs & dispatches proteins.
• C. ER → Transport, not final packaging.
• D. Vacuole → Storage.

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