Lipid Metabolism — Flashcards

Flashcard 81: _____-carbon steroids, such as DHEA and androstenedione, have androgenic activity and are precursors to estrogen

Answer: 19

Flashcard 82: The enzyme lipoprotein lipase is activated by _____ and apoprotein C-II

Answer: insulin

Extra: Lipoprotein lipase (LPL) is an enzyme located on the vascular endothelial surface that hydrolyzes triglycerides in chylomicrons and VLDL. Key regulatory points: 1. **Apoprotein C-II**: A mandatory cofactor for LPL activation. 2. **Insulin**: Stimulates LPL synthesis and secretion in adipose tissue (promoting fat storage in the well-fed state). 3. **Tissue Specificity**: In contrast to adipose tissue, LPL in cardiac and skeletal muscle has a lower Km (higher affinity) and is not stimulated by insulin, allowing muscle to prioritize lipid uptake even when glucose is low.

Flashcard 83: In the liver, bile acids are conjugated to the amino acids _____ or taurine to form bile salts

Answer: glycine

Flashcard 84: _____ is a PUFA containing 5 double bonds

Answer: Timnodonic acid

Flashcard 85: On the cellular surface of hepatocytes, the LDL particle binds a _____ receptor via apoprotein B-100

Answer: LDL

Flashcard 86: The serum lipoproteins elevated in type III familial dyslipidemia (dysbetalipoproteinemia) are _____ and IDL (VLDL remnants).

Answer: chylomicron remnants

Flashcard 87: Apo B-_____ is found only on particles originating from the intestines, whereas Apo B-100 is found only on particles originating from the liver

Answer: 48

Flashcard 88: Acetyl-CoA is converted to _____ via the enzyme acetyl-CoA carboxylase (fatty acid synthesis)

Answer: malonyl-CoA

Flashcard 89: _____ adds triglycerides to nascent VLDL in the liver and to chylomicrons in the intestine.

Answer: MTP

Flashcard 90: Gallstone chemistry most commonly seen is _____ cholesterol monohydrate

Answer: crystalline