UPSC Prelims 2004 Q11: Science & Technology – Biology
The hormone insulin is a
- (a) Glycolipid
- (b) Fatty acid
- (c) Peptide
- (d) Sterol
Answer: (c) Peptide
Explanation
Chemical nature of insulin
| Option | Insulin? |
|---|---|
| Peptide | Yes — a protein hormone of 51 amino acids |
| Glycolipid | No |
| Fatty acid | No |
| Sterol | No — sex hormones and cortisol are steroids |
Insulin is a peptide (protein) hormone secreted by the beta cells of the pancreas.
Answer: (c) Peptide.
Why each option is right or wrong
- (a) Incorrect. Glycolipids are not hormones like insulin.
- (b) Incorrect. Fatty acids are not the nature of insulin.
- (c) CORRECT. Insulin is a peptide hormone.
- (d) Incorrect. Sterols are steroid-type compounds.
Key point
Peptide hormones: insulin, glucagon, ADH; steroid hormones: cortisol, estrogen.
Remember
Insulin is a peptide hormone of the pancreas.
Common mistakes
- Mixing insulin with steroid hormones.
- Thinking all hormones are lipids.
- Forgetting that insulin is made of two peptide chains.
Exam tip
Insulin: first protein sequenced, by Sanger.
Sources
- NCERT Class XI Biology — Chemical Coordination
- NCERT Class XII Chemistry — Biomolecules (proteins and hormones)