GATE 2021 BT – Question 24
A protein without its prosthetic group is known as
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Correct answer: (A) apoprotein
Explanation
A conjugated protein has two parts:
- the protein part, and
- a non-protein part called the **prosthetic group** (for example haem, a metal ion, or a vitamin).
The names:
- **Apoprotein:** the protein **without** its prosthetic group (inactive). ✓
- **Holoprotein:** the apoprotein **with** its prosthetic group, the complete active form.
- **Haemoprotein:** a protein that has a haem group (such as haemoglobin).
- **Lipoprotein:** a protein combined with lipids.
Answer **apoprotein** (A).