Question

Given below are two statements: Assertion (A): Caveolae are enriched in cholesterol and glycerophospholipids. Reason (R): Caveolin binds cholesterol in the membrane and forces the associated lipid bilayer to curve inward to form caveolae.

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A).
• B. Both (A) and (R) are correct but (R) is NOT the correct explanation of (A).
• C. (A) is correct but (R) is not correct.
• D. (A) is not correct but (R) is correct.

Hint:

Caveolae = Cholesterol + Sphingolipids + Caveolin. Think of Caveolin as the “shaper” of the cave.

Answer 1

The Correct Option is D

Step 1: Concept
Caveolae are small, flask-shaped invaginations of the plasma membrane involved in endocytosis and cell signalling.

Step 2: Meaning
Their structure is maintained by specific proteins and a unique lipid composition.

Step 3: Analysis
Assertion (A) is incorrect because caveolae are enriched in cholesterol and sphingolipids (not glycerophospholipids). Reason (R) is correct: caveolin directly binds cholesterol and induces the membrane curvature required to form the flask-like shape.

Step 4: Conclusion
The assertion contains a factual error, but the reason is accurate.

Final Answer: (D)