UPSC Prelims 2008 Q132: Science & Technology – Biology
- (a) Both A and R are individually true and R is the correct explanation of A
- (b) Both A and R are individually true but R is not the correct explanation of A
- (c) A is true but R is false
- (d) A is false but R is true
Answer: (c) A is true but R is false
Explanation
Checking an Assertion-Reason pair on liver function
Assertion (A): The liver plays an important role in fat digestion.
Reason (R): The liver produces two important fat-digesting enzymes.
| Statement | Verdict | Reason |
|---|---|---|
| Assertion (A) | True | The liver does play an important role in fat digestion, primarily by producing bile, which emulsifies fats |
| Reason (R) | False | The liver produces bile (which aids fat digestion by emulsification), but it does NOT produce the actual fat-digesting enzymes (lipase) — those come from the pancreas |
Why A is true but R is false:
| Point | Detail |
|---|---|
| Liver's actual role | Produces bile (emulsifies fat, aiding digestion) |
| Fat-digesting enzyme (lipase) | Produced by the pancreas, NOT the liver |
Answer: (c) A is true but R is false.
Why each option is right or wrong
- (a) Incorrect. R is false (liver doesn't produce digestive enzymes), so it cannot correctly explain A.
- (b) Incorrect. R is false, not merely a non-explanatory true statement.
- (c) CORRECT. A is true (liver aids fat digestion via bile), but R is false (liver doesn't produce fat-digesting enzymes; that's the pancreas's role).
- (d) Incorrect. A is true, not false.
Key point
The liver DOES aid fat digestion (via bile production), but it does NOT produce fat-digesting enzymes (lipase) — that is the pancreas's role, making Reason (R) false while Assertion (A) remains true.
Remember
Liver aids fat digestion via bile (true) — but does NOT produce fat-digesting enzymes; that's the pancreas's role (so the Reason is false).
Common mistakes
- Confusing bile production (liver) with enzyme production (pancreas) for fat digestion.
- Assuming the liver's role in digestion must involve enzymes specifically, rather than bile.
- Not distinguishing between an organ's true function and an incorrectly attributed mechanism.
Exam tip
Liver = produces bile (emulsifies fat). Pancreas = produces fat-digesting enzymes (lipase). Keep these two organs' digestive roles separate.
Sources
- NCERT Class XI Biology — Digestion and Absorption
- John E. Hall — Guyton and Hall Textbook of Medical Physiology (Secretory Functions of the Alimentary Tract)