Lipid Metabolism Exam Review

These flashcards cover the key concepts of lipid metabolism, including digestion, transport, synthesis, and oxidation of lipids.

What are the main components of lipoproteins?

A lipoprotein contains a core of neutral lipids, including triacylglycerols and cholesteryl esters, surrounded by a layer of phospholipids, proteins, and cholesterol.

What is the role of bile acids in lipid digestion?

Bile acids emulsify triacylglycerols by forming micelles in the small intestine.

What is the main bile acid mentioned in the lecture?

The major bile acid mentioned is cholic acid.

How are chylomicrons formed?

Chylomicrons are formed when water-insoluble acylglycerols and larger fatty acids are packaged for transport into the bloodstream.

What is the function of pancreatic lipase in lipid metabolism?

Pancreatic lipase partially hydrolyzes emulsified triacylglycerols into mono- and diacylglycerols plus fatty acids.

What is the primary function of lipoproteins?

Lipoproteins transport lipids in the bloodstream.

What are the five major types of lipoproteins and their functions?

Chylomicrons transport dietary lipids; VLDLs transport triacylglycerols from the liver; IDLs carry remnants of VLDL; LDLs transport cholesterol to tissues; HDLs carry cholesterol back to the liver.

What happens to dietary triacylglycerols after they are absorbed?

They are transported as chylomicrons through the lymphatic system to the bloodstream and liver.

How are fatty acids released from adipose tissue used for energy?

Fatty acids released associate with albumin to be transported to energy-generating cells.

What hormone levels activate the mobilization of triacylglycerols?

Low insulin and high glucagon levels activate the mobilization of triacylglycerols.

What metabolic pathway does acetyl-CoA enter after fatty acid oxidation?

Acetyl-CoA enters the citric acid cycle for further oxidation.

What is the energy yield from one cycle of fatty acid oxidation?

Each cycle produces one acetyl-CoA and reduces coenzymes NADH and FADH2 for ATP generation.

What is ketogenesis?

Ketogenesis is the synthesis of ketone bodies from acetyl-CoA, occurring when there is excess acetyl-CoA in the liver.

What are the three main ketone bodies?

3-hydroxybutyrate, acetoacetate, and acetone.

What condition can arise from excessive production of ketone bodies?

Ketoacidosis can occur due to the accumulation of ketone bodies in the bloodstream.

What is the ideal total cholesterol/HDL ratio?

An ideal ratio is 3.5, with a ratio of 5 or higher indicating a high risk of heart disease.

How is fatty acid activation achieved?

By converting fatty acids to fatty acyl-CoA in a reaction that invests energy from ATP.

What is the function of acyl transferase in triacylglycerol synthesis?

Acyl transferase catalyzes the transfer of fatty acid acyl groups to glycerol 3-phosphate.

What roles do glycerol and fatty acids play in triacylglycerol mobilization?

Glycerol is converted to glucose intermediates, while fatty acids are oxidized for energy.

Name the two main pathways acetyl-CoA can enter.

The citric acid cycle and fatty acid synthesis pathways.

What is a lipoprotein lipase's role in fat metabolism?

Lipoprotein lipase hydrolyzes triacylglycerols in blood to release fatty acids and glycerol.

Describe the relationship between fatty acid synthesis and oxidation.

Both processes involve the addition or removal of two carbon atoms at a time but occur in different cell locations and utilize different enzymes.

What role does insulin play in lipid metabolism?

Insulin promotes the synthesis and storage of triacylglycerols post-meal.

What are the two main sources of lipids for the body?

Lipids are sourced from the diet and stored adipose tissue.

What impact does a high saturated fat diet have on cholesterol levels?

It increases blood serum cholesterol levels.

What is the role of acetyl-CoA in energy metabolism?

Acetyl-CoA serves as a substrate for energy generation and is involved in synthesis pathways for lipids and ketone bodies.

How does exercise affect triacylglycerol mobilization?

Exercise stimulates the hydrolysis of stored triacylglycerols for energy.

Explain the process of fatty acid oxidation systematically.

Fatty acid oxidation involves three steps: activation to form fatty acyl-CoA, transport into mitochondria, and beta-oxidation to yield acetyl-CoA.