A medical student lists end products derived from the mevalonate pathway besides cholesterol. Which of the following is correctly matched to its origin from this pathway?
- A Ubiquinone and dolichol, from farnesyl pyrophosphate precursors ✓
- B Heme, from farnesyl pyrophosphate
- C Bile acids, from squalene directly
- D Vitamin D, from lanosterol
Correct answer: A. Ubiquinone and dolichol, from farnesyl pyrophosphate precursors
Explanation
Beyond cholesterol, the isoprenoid branch of the mevalonate pathway yields farnesyl pyrophosphate, the precursor of ubiquinone (coenzyme Q), dolichol (needed for N-linked glycoprotein synthesis), and the prenyl groups attached to signaling proteins such as Ras. Heme derives from glycine and succinyl-CoA, bile acids arise from cholesterol itself via 7-alpha-hydroxylation, and vitamin D comes from 7-dehydrocholesterol photolysis in skin.
Reference: Harper's Illustrated Biochemistry, 32nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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