🧬 The Fundamental Unit of Life – Class 9 Science MCQs

Section 1: Discovery & Introduction to Cell Theory (Q1–Q25)

Q1. Who discovered the cell in 1665?

A. Robert Brown
B. Robert Hooke
C. Schleiden
D. Schwann

✅ Correct Answer: B. Robert Hooke

Explanation:

• A. Robert Brown → Discovered the nucleus.
• B. Robert Hooke → Correct, observed cork cells under microscope in 1665.
• C. Schleiden → Proposed cell theory for plants.
• D. Schwann → Extended cell theory to animals.

Q2. Robert Hooke observed cells in which material?

A. Onion peel
B. Cork
C. Cheek cell
D. Bacteria

✅ Correct Answer: B. Cork

Explanation:

• A. Onion peel → Used later for observing living cells.
• B. Cork → Correct, Hooke saw dead cells in cork.
• C. Cheek cell → Animal cell studied later.
• D. Bacteria → Seen by Leeuwenhoek.

Q3. Who discovered the nucleus in a cell?

A. Robert Hooke
B. Schleiden
C. Robert Brown
D. Virchow

✅ Correct Answer: C. Robert Brown

Explanation:

• A. Hooke → Discovered cells.
• B. Schleiden → Plant cell theory.
• C. Robert Brown → Correct, nucleus discovery (1831).
• D. Virchow → “Cell arises from cell.”

Q4. Who proposed cell theory?

A. Schleiden and Schwann
B. Hooke and Brown
C. Virchow and Brown
D. Darwin and Wallace

✅ Correct Answer: A. Schleiden and Schwann

Explanation:

• A. Correct, Schleiden (plants) and Schwann (animals).
• **B. Wrong pair.
• **C. Virchow later added.
• **D. Wrong, they proposed evolution theory.

Q5. “Omnis cellula e cellula” means:

A. Cell arises from dead matter
B. Cell is basic unit of life
C. Cell arises from pre-existing cell
D. Cell is immortal

✅ Correct Answer: C. Cell arises from pre-existing cell

Explanation:

• **A. Wrong, not from dead matter.
• **B. Part of cell theory, but not this phrase.
• **C. Correct, Virchow’s principle.
• **D. Wrong.

Q6. Who first observed living cells?

A. Hooke
B. Leeuwenhoek
C. Brown
D. Schwann

✅ Correct Answer: B. Leeuwenhoek

Explanation:

• A. Hooke → Observed dead cells in cork.
• **B. Correct, Leeuwenhoek saw living cells in pond water.
• C. Brown → Nucleus.
• D. Schwann → Animal cell theory.

Q7. Cell theory states:

A. All cells contain nucleus
B. Cell is smallest structural and functional unit
C. Cells only occur in plants
D. All cells are identical

✅ Correct Answer: B. Cell is smallest structural and functional unit

Explanation:

• **A. Wrong, some cells lack nucleus (prokaryotes).
• **B. Correct.
• **C. Wrong, animals too have cells.
• **D. Wrong, different cells vary in structure.

Q8. The cell is called structural and functional unit of life because:

A. It forms all tissues and organs
B. All living functions are performed by cells
C. It contains hereditary material
D. All of these

✅ Correct Answer: D. All of these

Explanation:

• **A. Correct, cells build tissues/organs.
• **B. Correct, cells perform life processes.
• **C. Correct, DNA in nucleus.
• **D. All statements true.

Q9. Which one is NOT part of cell theory?

A. All living beings are made of cells
B. Cell is basic unit of life
C. Cells arise spontaneously
D. Cells arise from pre-existing cells

✅ Correct Answer: C. Cells arise spontaneously

Explanation:

• A, B, D → True as per cell theory.
• C. Wrong, rejected theory of spontaneous generation.

Q10. Which cell is longest in human body?

A. Muscle cell
B. Nerve cell
C. Red blood cell
D. Skin cell

✅ Correct Answer: B. Nerve cell

Explanation:

• **A. Muscle cells are long but not longest.
• **B. Correct, neurons may be over 1 meter.
• **C. RBCs are small and biconcave.
• **D. Skin cells small and flat.

Q11. Which cell is round and biconcave?

A. Nerve cell
B. RBC
C. WBC
D. Guard cell

✅ Correct Answer: B. RBC

Explanation:

• **A. Nerve → Long and branched.
• **B. RBC → Correct, round and biconcave to carry oxygen.
• **C. WBC → Irregular shape.
• **D. Guard cells → Kidney-shaped in stomata.

Q12. What is the average size of an animal cell?

A. 0.1–0.5 μm
B. 10–30 μm
C. 100–200 μm
D. 1–2 mm

✅ Correct Answer: B. 10–30 μm

Explanation:

• **A. 0.1–0.5 μm → Bacteria size.
• **B. Correct.
• **C. 100–200 μm → Large plant cells.
• **D. Wrong.

Q13. Cell wall is present in:

A. Animal cells
B. Plant cells
C. Both
D. Neither

✅ Correct Answer: B. Plant cells

Explanation:

• **A. Absent in animals.
• **B. Correct, cell wall of cellulose.
• **C. Not both.
• **D. Wrong.

Q14. Protoplasm = ?

A. Cytoplasm + Nucleus
B. Cytoplasm + Cell wall
C. Nucleus only
D. Cytoplasm only

✅ Correct Answer: A. Cytoplasm + Nucleus

Explanation:

• **A. Correct, living part of cell.
• **B. Cell wall not living.
• **C. Wrong, nucleus only not enough.
• **D. Wrong, cytoplasm only.

Q15. Smallest cell in human body is:

A. RBC
B. WBC
C. Nerve cell
D. Sperm

✅ Correct Answer: A. RBC

Explanation:

• **A. RBC ≈ 6–8 μm → Correct.
• **B. WBC slightly larger.
• **C. Nerve cell is longest, not smallest.
• **D. Sperm longer than RBC.

Q16. Which of the following is true for prokaryotes?

A. Lack true nucleus
B. Lack membrane-bound organelles
C. DNA present in nucleoid
D. All of these

✅ Correct Answer: D. All of these

Explanation:

• **A. True, no nuclear membrane.
• **B. True, no mitochondria, plastids.
• **C. True, DNA free in cytoplasm.
• **D. All correct.

Q17. Example of prokaryotic cell is:

A. Amoeba
B. Bacteria
C. Fungi
D. Hydra

✅ Correct Answer: B. Bacteria

Explanation:

• **A. Amoeba → Eukaryotic.
• **B. Bacteria → Correct, prokaryotic.
• **C. Fungi → Eukaryotic.
• **D. Hydra → Multicellular eukaryote.

Q18. Which is true for eukaryotic cells?

A. Have true nucleus
B. Have membrane-bound organelles
C. Found in plants and animals
D. All of these

✅ Correct Answer: D. All of these

Explanation:

• **A. Correct.
• **B. Correct.
• **C. Correct.
• **D. All correct.

Q19. Cell theory was modified by Virchow in which year?

A. 1831
B. 1839
C. 1855
D. 1869

✅ Correct Answer: C. 1855

Explanation:

• **A. 1831 → Brown discovered nucleus.
• **B. 1839 → Schwann’s contribution.
• **C. 1855 → Virchow added “cell from pre-existing cell.”
• **D. Wrong.

Q20. Cell is discovered by Hooke in which year?

A. 1665
B. 1600
C. 1831
D. 1855

✅ Correct Answer: A. 1665

Explanation:

• **A. Correct.
• **B. Too early.
• **C. Nucleus discovery.
• **D. Virchow’s contribution.

Q21. Which one is absent in prokaryotes?

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

✅ Correct Answer: C. Nucleus with nuclear membrane

Explanation:

• **A. Bacteria have cell wall.
• **B. Plasma membrane present.
• **C. Correct, true nucleus absent.
• **D. Cytoplasm present.

Q22. The term “cell” was given by:

A. Brown
B. Hooke
C. Leeuwenhoek
D. Schwann

✅ Correct Answer: B. Hooke

Explanation:

• **A. Nucleus.
• **B. Correct, coined word “cell.”
• **C. First saw living cells.
• **D. Wrong.

Q23. Protoplasm was described as physical basis of life by:

A. Huxley
B. Virchow
C. Hooke
D. Brown

✅ Correct Answer: A. Huxley

Explanation:

• **A. Correct.
• **B. Cell theory.
• **C. Cells discovery.
• **D. Nucleus.

Q24. All living cells arise from pre-existing cells. This was proposed by:

A. Schwann
B. Schleiden
C. Virchow
D. Leeuwenhoek

✅ Correct Answer: C. Virchow

Explanation:

• **A. Animal cell theory.
• **B. Plant cell theory.
• **C. Correct, Virchow (1855).
• **D. Wrong.

Q25. Which is correct for unicellular organisms?

A. Made of many cells
B. A single cell performs all life functions
C. Cannot reproduce
D. Found only in plants

✅ Correct Answer: B. A single cell performs all life functions

Explanation:

• **A. Wrong, only one cell.
• **B. Correct, e.g., Amoeba.
• **C. Wrong, unicellular organisms reproduce.
• **D. Wrong, present in animals (Protozoa) too.

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