Cholesterol derivatives — Cholesterol serves as a biochemical precursor for which of the following molecules in human physiology?

Introduction:
Cholesterol is more than a membrane component; it is a versatile precursor for several vital molecules. This question checks your knowledge of which products are biosynthesized from cholesterol in humans.

Given Data / Assumptions:

• Cholesterol is synthesized from acetyl-CoA via the mevalonate pathway.
• Downstream pathways convert cholesterol into hormones and detergents for lipid digestion.
• Vitamin A originates from carotenoids, not from cholesterol.

Concept / Approach:
In endocrine tissues, cholesterol is converted into steroid hormones (glucocorticoids, mineralocorticoids, and sex steroids). In the liver, cholesterol is oxidized to bile acids/salts (e.g., cholic acid) that emulsify dietary lipids. Vitamin A derives from dietary carotenoids (beta-carotene), not from cholesterol, distinguishing option (d) as correct.

Step-by-Step Solution:

Verification / Alternative check:
Clinical pharmacology (e.g., statins affecting cholesterol availability) can influence steroidogenesis and bile acid pools, underscoring cholesterol’s precursor role.

Why Other Options Are Wrong:

• Vitamin A: not cholesterol-derived.
• Single selections (a) or (c) omit one correct pathway; (e) wrongly pairs steroid hormones with vitamin A.

Common Pitfalls:
Confusing fat-soluble vitamins: vitamin D is secosteroidal and can be produced from 7-dehydrocholesterol in skin, but vitamin A is not derived from cholesterol.

Final Answer:
both (a) and (c).