Lipid Metabolism Flashcards
What are the main functions of fatty acids (FA) in the body?
They serve as a major energy source, are stored in adipose tissue, and can be synthesized from excess glucose in the liver.
What is β-oxidation, and where does it occur?
β-oxidation is the process of fatty acid breakdown to produce acetyl-CoA, NADH, and FADH₂, occurring in the mitochondria.
What are the main steps in β-oxidation of fatty acids?
Activation, transport into mitochondria via the carnitine shuttle, and repetitive cycles of oxidation producing acetyl-CoA, NADH, and FADH₂.
How much ATP is generated from the breakdown of one 16-carbon fatty acid?
Approximately 129 ATP, after accounting for activation energy.
What is the role of acetyl-CoA carboxylase in fatty acid synthesis?
It is the rate-limiting enzyme that converts acetyl-CoA to malonyl-CoA, the starting molecule for fatty acid synthesis.
What is the function of fatty acid synthase?
It is a multi-enzyme complex that synthesizes palmitate (16-carbon fatty acid) through a series of condensation, reduction, dehydration, and reduction reactions.
Why is HMG-CoA reductase significant in cholesterol synthesis?
It is the rate-limiting enzyme targeted by statins to lower cholesterol levels, as it catalyzes the formation of mevalonate.
What are the five stages of cholesterol synthesis?
Synthesis of mevalonate, isopentenyl pyrophosphate (IPP), squalene, formation of the steroid nucleus, and conversion to cholesterol.
What are the potential consequences of excess cholesterol?
It can lead to atherosclerosis and cardiovascular diseases; hence, cholesterol synthesis is tightly regulated.
What are the main uses of cholesterol in the body?
It is a precursor for steroid hormones, bile acids, and vitamin D, and helps maintain cell membrane fluidity.
