Govt. Exams
Entrance Exams
LCAT is synthesized primarily in the liver and, to a lesser extent, in other tissues. It plays a crucial role in HDL remodeling by converting free cholesterol to cholesterol esters.
Insulin activates mTORC1, which promotes protein synthesis and lipogenesis. It also increases acetyl-CoA carboxylase activity, promoting fatty acid synthesis from carbohydrate sources.
Niemann-Pick Type C results from mutations in NPC1 or NPC2 genes, which encode lysosomal cholesterol transporters, leading to lysosomal accumulation of cholesterol and sphingolipids.
ApoB-100 is essential for the structural integrity and secretion of VLDL and LDL particles. It remains with these particles throughout their metabolism.
Ketone bodies (acetoacetate, beta-hydroxybutyrate, and acetone) are synthesized primarily in the liver mitochondria during periods of high fatty acid oxidation.
HDL has approximately 50% protein content, the highest among all lipoproteins. Chylomicrons and VLDL are triglyceride-rich lipoproteins with lower protein ratios.
Familial hypercholesterolemia presents with xanthomas due to defective LDL receptors. Type II hyperlipoproteinemia (IIa) is essentially familial hypercholesterolemia with elevated LDL. Both terms describe the same condition in this clinical context.
AMPK phosphorylates and inactivates acetyl-CoA carboxylase during energy stress (high AMP/ATP ratio), thereby reducing fatty acid synthesis. Citrate and insulin activate the enzyme.
The liver is the primary site of lipogenesis, where excess carbohydrates and amino acids are converted to fatty acids and triglycerides for storage and export via VLDL.
Cortisol and other corticosteroids are synthesized from cholesterol in the adrenal cortex through a series of enzymatic reactions involving cytochrome P450 enzymes.
