2024 CPPS 303 - Lipid Metabolism 2 New Questions and Answers ( Included ) 100% Correct
- What are chylomicrons made up of?
Answer: TAG, phospholipids, cholesterol and apolipoproteins
- Where are chylomicrons synthesized?
Answer: In the intestine
- How do chylomicrons pass from the lymph to the blood?
Answer: via the thoracic duct
- What enzyme located on the walls of capillary endothelium in adipose tissue and
muscle partially digests chylomicron TAG?
Answer: Lipoprotein lipase (LPL)
- What is the result of chylomicron TAG digestion?
Answer: Glycerol, fatty acids, and chylomicron remnants, which are triacyglycerol depleted and thus enriched in cholesterol
- Where do glycerol and fatty acid enter?
Answer: adipocytes and muscle cells
- What happens to chylomicron remnants
Answer: They remain in the blood and are transported to the liver, where they enter hepatocytes, by receptor-mediated endo- cytosis
- What are the cell surface receptors for chylomicron remnants entering he-
patocytes Answer: heparan sulfate proteoglycans, low-density lipoprotein-related receptors
- What happens to the chylomicron remnants after entry into hepatocytes?-
Answer: degradation by lysosomes
- Where do chylomicrons transport dietary TAG?
Answer: adipose tissue and muscle
- Where do chylomicron remnants transport dietary TAG and cholesterol?
Answer: - hepatocytes
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- What can take up LDL by receptor-mediated endocytosis?
Answer: liver and extra- hepatic tissues
- What are the major carriers of cholesterol in plasma?
Answer: LDL
- What is a major pathway of cholesterol input to the liver
Answer: LDL uptake by the liver
- What is the half life of LDL?
Answer: 2-3 days
- What is the purpose of LDL uptake by other tissues?
Answer: Deliery of cholesterol for the synthesis of cell membranes and steroid
hormones or for storage as choles teryl ester in dropletsd
- What does the cholesterol transporter ABCA1 in the peripheral cells facil iate?
Answer: efflux of cholesterol
- What does the enzyme lecithin-cholesterol acyltransferase do?
Answer: associated with HDL and esterfies cholesterol turning it into cholesteryl ester (CE)
- What mediates lipid transfer between lipoprotein classes?
Answer: cholesteryl ester transfer protein (CETP)
- How does CETP transfer CE?
Answer: From HDL -> VLDL, IDL, LDL
- How does CETP transfer TG
Answer: From VLDL, IDL, LDL -> HDL
- What binds scavenger refeptor class B type 1 (SR-B1) once it reaches the liver?
Answer: CE-enriched HDL
- What does SR-B1 mediate?
Answer: selective uptake of HDL-CE
- What happens when the body wants to uptake by the LDL receptor?
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Answer: The selective uptake of CE by SR-B1 does not involve endocytosos