UPSC Prelims 2020 Q47: Science & Technology – Biology
Which of the following statements are correct regarding the general difference between
plant and animal cells ?
1. Plant cells have cellulose cell walls whilst animal cells do not.
2. Plant cells do not have plasma membrane unlike animal cells which do.
3. Mature plant cell has one large vacuole whilst animal cell has many small vacuoles.
Select the correct answer using the code given below:
- (a) 1 and 2 only
- (b) 2 and 3 only
- (c) 1 and 3 only
- (d) 1, 2 and 3
Answer: (c) 1 and 3 only
Explanation
Plant cells vs animal cells
| Statement | Verdict | Fact |
|---|---|---|
| 1. Plant cells have cellulose cell walls; animal cells do not | Correct | Only plant cells have a rigid cellulose cell wall |
| 2. Plant cells lack a plasma membrane, unlike animal cells | Incorrect | Both have a plasma membrane; in plants it lies just inside the cell wall |
| 3. A mature plant cell has one large vacuole; animal cells have many small ones | Correct | Plant cells have a large central vacuole filled with cell sap |
Other differences:
| Feature | Plant cell | Animal cell |
|---|---|---|
| Chloroplasts | Present | Absent |
| Centrioles | Usually absent | Present |
| Shape | Fixed, often rectangular | Irregular, rounded |
Answer: (c) 1 and 3 only.
Why each option is right or wrong
- (a) Incorrect. Statement 2 is false: plant cells do have a plasma membrane.
- (b) Incorrect. It keeps the false statement 2 and drops the cell wall difference.
- (c) CORRECT. Only plant cells have a cellulose wall and a large central vacuole.
- (d) Incorrect. Every living cell has a plasma membrane, so statement 2 fails.
Key point
Plant cells: cellulose cell wall, large central vacuole, chloroplasts. Both plant and animal cells have a plasma membrane.
Remember
Plants add a wall and a big vacuole; both have membranes.
Common mistakes
- Thinking the cell wall replaces the plasma membrane in plants; plants have both.
- Forgetting that animal cells have small, temporary vacuoles rather than none.
- Mixing up the cell wall (outside) and plasma membrane (inside) layers.
Exam tip
Every living cell has a plasma membrane. Any statement denying it is false.
Sources
- NCERT Class IX — Science, Ch 5 (The Fundamental Unit of Life)
- NCERT Class XI — Biology, Ch 8 (Cell: The Unit of Life)