LDL Metabolism: Composition and Functions

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Which of the following statements is correct regarding LDL formation?

LDL particles are produced from chylomicrons after the hydrolysis of triglycerides by lipoprotein lipase.

LDL particles are synthesized in the liver from cholesterol and phospholipids.

LDL particles are formed from HDL after the removal of apolipoproteins.

LDL particles are formed from VLDL after most of their triglycerides have been degraded by lipoprotein lipase. (correct)

What is the primary function of LDL particles?

To provide cholesterol to peripheral tissues and return it to the liver. (correct)

To transport triglycerides from the liver to peripheral tissues.

To transport HDL particles from the liver to peripheral tissues.

To facilitate the absorption of dietary cholesterol in the intestine.

Which of the following statements is correct regarding the regulation of cholesterol content in cells with an active LDL pathway?

The released cholesterol stimulates the formation of HMG-CoA reductase, thereby increasing de novo synthesis of cholesterol, and LDL receptors are not subjected to feedback regulation.

The released cholesterol suppresses the formation of HMG-CoA reductase, thereby inhibiting de novo synthesis of cholesterol, but LDL receptors are not subjected to feedback regulation.

The released cholesterol has no effect on the formation of HMG-CoA reductase, but LDL receptors are subjected to feedback regulation.

The released cholesterol suppresses the formation of HMG-CoA reductase, thereby inhibiting de novo synthesis of cholesterol, and LDL receptors are subjected to feedback regulation. (correct)

Which of the following apolipoproteins is found in LDL particles?

Apo B-100 (C) Signup and view all the answers

Which of the following conditions is associated with high levels of LDL cholesterol?

Low physical activity, unhealthy diets, and obesity. (A) Signup and view all the answers

What is the clinical implication of high LDL cholesterol levels?

Increased risk of developing atherosclerosis and cardiovascular disease. (A) Signup and view all the answers

What is the primary function of VLDL?

To carry endogenous TG from the liver to the peripheral tissues (C) Signup and view all the answers

What happens to VLDL as they pass through the circulation?

They decrease in size and become denser (D) Signup and view all the answers

Where are chylomicron remnants primarily removed from the circulation?

Liver (B) Signup and view all the answers

What role does Apo B-100 play in VLDL composition?

It is required for VLDL synthesis (B) Signup and view all the answers

Which protein is responsible for facilitating the exchange of triglycerides and cholesteryl esters between HDL and VLDL?

Cholesteryl Ester Transfer Protein (CETP) (D) Signup and view all the answers

In what conditions can non-alcoholic fatty liver occur?

Obesity and type 2 diabetes mellitus (A) Signup and view all the answers

Which of the following statements about lipoprotein lipase (LPL) is correct?

LPL is involved in the hydrolysis of triglycerides in VLDL and chylomicrons (A) Signup and view all the answers

What is the primary role of HDL particles in lipid metabolism?

To transport cholesterol from peripheral tissues to the liver (C) Signup and view all the answers

Which of the following statements about the formation of LDL particles is correct?

LDL particles are formed from the hydrolysis of VLDL by LPL (C) Signup and view all the answers

Which of the following apolipoproteins is required for the receptor-mediated endocytosis of chylomicron remnants?

Apo E (A) Signup and view all the answers

What is the primary function of the enzyme lecithin:cholesterol acyltransferase (LCAT)?

To esterify cholesterol taken up by HDL particles (A) Signup and view all the answers

Which of the following statements about VLDL synthesis is correct?

VLDL particles are synthesized primarily by the liver (D) Signup and view all the answers