Lecture on Lipid Metabolism and Disorders

A comprehensive set of flashcards covering key concepts in lipid metabolism, associated factors, and disorders for exam preparation.

What factors affect protein synthesis?

Decreased essential amino acids, hereditary abeta or hypobetalipoproteinemia, and liver toxins.

What are lipotropic factors?

Substances that help mobilize fat from the liver and are essential for synthesizing plasma lipoproteins.

What causes primary hyperlipoproteinemia?

Congenital deficiency of plasma lipoprotein lipase enzyme.

What role does the liver play in lipid metabolism?

The liver uptakes absorbed lipids, synthesizes fatty acids, converts cholesterol, oxidizes fatty acids, and more.

What is a primary cause of fatty liver?

Overfeeding of fats leading to excessive TAG accumulation in the liver.

What are the consequences of hypercholesterolemia?

It can lead to atherosclerosis and its complications, including hypertension and myocardial infarction.

What is the role of HDL in cholesterol metabolism?

HDL removes cholesterol from tissues and transports it to the liver.

How is VLDL formed?

VLDL is synthesized in the liver by assembling lipids, including TAG, cholesterol, and apoproteins.

What happens during the metabolism of chylomicrons?

Chylomicrons transport dietary lipids from the intestine to the bloodstream and undergo hydrolysis.

What factors affect phospholipid synthesis?

Decreased essential fatty acids, inositol, choline, and methyl donors.

What is abetalipoproteinemia?

A condition due to the failure of synthesis of apo-B, leading to decreased formation of lipoproteins.

What is the significance of LCAT in HDL metabolism?

LCAT (lecithin cholesterol acyl transferase) helps convert free cholesterol into cholesterol esters.

What consequence does excessive intake of nicotinic acid have?

It produces depletion of methyl donors needed for choline synthesis.

What deficiency causes an increase in free fatty acids levels in plasma?

Deficiency in lipoprotein lipase or excessive lipolysis.

What is the atherogenic index?

The ratio of LDL to HDL; an index above 4 indicates increased risk for atherosclerosis.

How do antioxidant vitamins affect atherosclerosis risk?

Vitamins A, C, E, and selenium may help in decreasing the risk of developing atherosclerosis.

What is the role of apo E in the metabolism of chylomicron remnants?

Apo E facilitates the entry of chylomicron remnants into liver cells.

What is the effect of insulin on lipoprotein lipase?

Insulin enhances the synthesis of lipoprotein lipase.

What is the primary consequence of hereditary abetalipoproteinemia?

Defective formation of chylomicrons, VLDL, and LDL.

What is the metabolic fate of LDL?

LDL provides cholesterol to extrahepatic tissues and the liver through specific receptors.

What is the importance of pantothenic acid in fatty acid metabolism?

It is needed for synthesizing coenzyme A (COASH) essential for fatty acid activation.

What happens in secondary hyperlipoproteinemia?

It occurs due to diseases that affect lipid metabolism, like diabetes and obesity.

What is the link between obesity and fatty liver?

Obesity may lead to excessive carbohydrates being converted to TAGs, contributing to fatty liver.

What are the signs of cholesterol ester deficiency?

Marked decrease in cholesterol esters and elevated disk-shaped HDL.

How are HDL particles formed?

By the liver and small intestines, initially in a disc shape, then modified in circulation.

What is atherosclerosis caused by?

It is caused by the deposition of lipids, mainly cholesterol, in arterial walls.

What role does carnitine play in fatty acid metabolism?

Carnitine helps transport fatty acids across the mitochondrial membrane for oxidation.

What is hyperlipoproteinemia associated with?

Increased levels of lipoproteins in the plasma, due to various metabolic conditions.

What happens to triglycerides in VLDL during metabolism?

They are hydrolyzed by lipoprotein lipase into free fatty acids and glycerol.

What factors are considered lipotropic?

Essential amino acids, fatty acids, inositol, and choline, among others.

What occurs when the LDL receptor is defective?

It results in reduced uptake of LDL, leading to increased plasma LDL cholesterol.

What is the effect of carbohydrate overfeeding on the liver?

It leads to storage of excess carbohydrates as glycogen, which can convert to TAG.

What is the role of macrophages in atherosclerosis?

They take up oxidized LDL particles, transforming into foam cells that accumulate in arterial walls.

What triggers gluconeogenesis in lipids metabolism?

Gluconeogenesis occurs from glycerol and odd-chain fatty acids during energy supply.

What impact does increased lipolysis have on the liver?

It leads to excessive fat transport to the liver, potentially causing fatty liver.

What are chylomicrons primarily composed of?

They are composed of triglycerides, cholesterol, phospholipids, and apoproteins.

How does cholesterol ester transfer protein affect HDL and VLDL?

It facilitates the transfer of cholesteryl esters to chylomicrons and VLDL.