CAPF AC 2021 Q6: Science & Technology – Biology
Which one of the following organelles is not found in animal cells?
- (a) Cell membrane
- (b) Endoplasmic reticulum
- (c) Cell wall
- (d) Lysosome
Answer: (c) Cell wall
Explanation
Structure absent in animal cells
How to think: recall the standard list of what plant cells have and animal cells lack.
There are three: cell wall, plastids (chloroplasts) and a large central vacuole.
Only one of them is in the options.
| Structure | Plant cell | Animal cell |
|---|---|---|
| Cell membrane | Present | Present |
| Cell wall (made of cellulose) | Present | Absent |
| Endoplasmic reticulum | Present | Present |
| Lysosome | Rare | Present |
| Plastids | Present | Absent |
| Large central vacuole | Present | Absent (only small vacuoles) |
| Centrioles | Absent in higher plants | Present |
Why animals have no cell wall: a rigid wall would stop cells from changing shape, which animals need for movement.
Answer: (c) Cell wall.
Why each option is right or wrong
- (a) Incorrect. Every cell, plant or animal, has a cell membrane.
- (b) Incorrect. The endoplasmic reticulum is found in both plant and animal cells.
- (c) CORRECT. The cell wall is found in plants, fungi and bacteria, not in animal cells.
- (d) Incorrect. Lysosomes are typical of animal cells; they are the cell's waste disposal system.
Key point
Plant cells have three things animal cells lack: cell wall, plastids and a large central vacuole. Animal cells have centrioles.
Remember
No cell wall in animal cells.
Common mistakes
- Confusing the cell wall with the cell membrane, which all cells have.
- Marking lysosome, which is in fact typical of animal cells.
- Thinking only plants have a cell wall; fungi and bacteria have one too.
Exam tip
Educated guess: the cell membrane and endoplasmic reticulum are basic to all cells, so (a) and (b) go. Lysosomes are an animal cell feature. Only the cell wall is left.
Sources
- NCERT Class IX Science — The Fundamental Unit of Life
- NCERT Class VIII Science — Cell: Structure and Functions