Question

Cholesterol biosynthesis involves a stepwise increase of carbon numbers from acetyl-CoA (C2) to ______ (C5), and, finally, to squalene (C30). But, the rate-limiting step is catalyzed by _____. Inhibition of this enzyme is adopted as a strategy for the therapeutic control of cholesterol levels.

Select one:

a. isoprenoid ;;; HMG CoA synthase

b. isoprenoid ;;; HMG CoA reductase

c. flavonoid ;;; HMG CoA synthase

d. flavonoid ;;; HMG CoA reductase

e. None of these

Answer 1

Answer = b. isoprenoid ;;; HMG CoA reductase

Cholesterol is synthesized via the isoprenoid biosynthetic pathway, which produces numerous biomolecules, called isoprenoids,

Cholesterol synthesis is regulated at the step involving HMG-CoA reductase.

The enzyme activity is regulated at the transcriptional level, that is, by changing the rate of synthesis of the mRNA encoding the enzyme. HMG-CoA reductase is regulated by phosphorylation and dephosphorylation