Cholesterol Synthesis & Regulation

What is the primary target of statins in cholesterol synthesis?

• HMG-CoA reductase enzyme

• Squalene synthase

• Acetyl-CoA carboxylase

• Cholesterol ester transfer protein

Which enzyme catalyzes the conversion of HMG-CoA to mevalonate in the cholesterol biosynthesis pathway?

• HMG-CoA reductase

• Mevalonate kinase

• Cholesterol synthase

• HMG-CoA synthase

What is the rate-limiting step in cholesterol biosynthesis?

• Transport of cholesterol into the mitochondria

• Conversion of HMG-CoA to mevalonate by HMG-CoA reductase

• Incorporation of cholesterol into cell membranes

• Conversion of mevalonate to HMG-CoA by HMG-CoA reductase

What are the precursors for cholesterol synthesis?

• Vitamin D

• Acetyl-coA

• Cholesterol synthase

• Lanosterolase

What is the end product of the cholesterol biosynthesis pathway?

• Protein

• Cholesterol

• Glucose

• Vitamin C

How does HMG-CoA reductase inhibition affect cholesterol synthesis?

• Inhibition of HMG-CoA reductase reduces cholesterol synthesis by blocking the production of mevalonate.

• Inhibition of HMG-CoA reductase leads to the breakdown of cholesterol synthesis intermediates.

• Inhibition of HMG-CoA reductase increases cholesterol synthesis by enhancing mevalonate production.

• Inhibition of HMG-CoA reductase has no effect on cholesterol synthesis.

Which enzyme is inhibited by statins to reduce cholesterol production?

• ATP synthase

• Acetyl-CoA carboxylase

• HMG-CoA reductase

• Cytochrome P450

What are the key regulatory mechanisms controlling cholesterol synthesis in the body?

• Enhancement by cholesterol, activation by SREBPs, and inhibition by hormones like insulin and glucagon.

• Feedback inhibition by glucose, regulation by LDL receptors, and modulation by vitamins like A and D.

• Feedback inhibition by cholesterol, regulation by SREBPs, and modulation by hormones like insulin and glucagon.

• Stimulation by triglycerides, control by PPARs, and suppression by dietary fiber.

What is the role of SREBPs in regulating cholesterol synthesis?

• Activation of HMG-CoA reductase

• Enhancement of cholesterol breakdown

• Stimulation of LDL receptor expression

• Transcriptional control of genes involved in cholesterol synthesis

How does the body maintain cholesterol homeostasis?

• By increasing cholesterol synthesis in response to high dietary intake

• By decreasing cholesterol absorption in the intestines

• By regulating the expression of LDL receptors

• By converting excess cholesterol into bile acids