Lipid Metabolism — Flashcards

Flashcard 91: 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 92: _____-carbon steroids, such as DHEA and androstenedione, have androgenic activity and are precursors to estrogen

Answer: 19

Flashcard 93: In the _____ cells of the ovary, androstenedione is converted to testosterone via the enzyme 17-hydroxysteroid dehydrogenase

Answer: granulosa

Flashcard 94: Fatty acid synthesis requires _____, which is provided directly from citrate

Answer: acetyl CoA

Flashcard 95: Peroxisomal beta-oxidation of VLCFAs lead to the formation of _____ and H2O2

Answer: octanoyl coA

Flashcard 96: Type _____ lipoproteinemia is due to a LPL or apo-CII deficiency

Answer: I

Flashcard 97: Type _____ familial dyslipidemia is characterized by a 'creamy' layer in supernatant

Answer: I

Flashcard 98: Cholesterol synthesis:Condensation of six _____ units form squalene

Answer: isoprenoid

Flashcard 99: Once depleted of their triglycerides, chylomicron _____ return to the liver

Answer: remnants

Flashcard 100: In extrahepatic tissues, acetoacetate is activated to _____ via the enzyme thiophorase (ketone body metabolism)

Answer: acetoacetyl-CoA