Biochem - Metabolism (Cholesterol synthesis, Lipid transport, & Familial dyslipidemias) Flashcards
Pg. 117-118 in First Aid 2014 Sections include: -Cholesterol synthesis -Lipid transport, key enzymes -Major apolipoproteins -Lipoprotein functions -Familial dyslipidemias
What is the rate-limiting step of cholesterol synthesis, and what enzyme catalyzes it? What substance induces the activity of this enzyme?
Rate-limiting step is catalyzed by HMG-CoA reductase (induced by insulin), which converts HMG-CoA to mevaolonate
What is LCAT, and what role does it play in cholesterol synthesis? What portion of cholesterol participates in its role?
2/3 of plasma cholesterol is esterified by lecithin-cholesterol acyltransferase (LCAT)
What is the mechanism of Statins? Give an example of a Statin.
Statins (e.g., lovastatin) competitively and reversibly inhibit HMG-CoA reductase.
What role does pancreatic lipase play in lipid transport?
Degradation of dietary triglycerides (TG) in small intestine
What role does lipoprotein lipase (LPL) play in lipid transport? Where are they found?
Degradation of TC circulating in chylomicrons and VLDLs. Found on vascular endothelial surface.
What role does Hepatic TG lipase (HL) play in lipid transport?
Degradation of TG remaining in IDL
What role does hormone-sensitive lipase play in lipid transport?
Degradation of TG stored in adipocytes
What role does LCAT play in lipid transport?
Catalyzes esterification of cholesterol
What role does cholesterol ester transfer protein (CETP) play in lipid transport?
Mediates transfer of cholesterol esters to other lipoprotein particles
Draw a diagram demonstrating the interconnections of lipid transport, including and labeling the following involved body parts: (1) Intestine (2) Liver (3) Adipose tissue (4) Capillary (5) Peripheral tissues (with LDL receptors). Also include the lipid transport steps that flow between them.
See p. 117 in First Aid 2014 for visual near top/middle of page
What are 2 major kinds of receptors on the liver involved in lipid transport?
(1) LDL receptors (2) Remnant (chylomicron remnants) receptors
Draw a diagram depicting the general actions of LCAT & CETP plus the organs involved.
See p. 117 in First Aid 2014 for visual near bottom/middle of page
Name 5 major apolipoproteins?
(1) E (2) A-1 (3) C-II (4) B-48 (5) B-100
What is the function of apolipoprotein E?
Mediates remnant uptake
Which of the following describes apolipoprotein E: (1) Chylomicron (2) Chylomicron remnant (3) VLDL (4) IDL (5) LDL (6) HDL?
(1) Yes (2) Yes (3) Yes (4) Yes (5) No (6) Yes
What is the function of apolipoprotein A-I?
Activates LCAT
Which of the following describes apolipoprotein A-I: (1) Chylomicron (2) Chylomicron remnant (3) VLDL (4) IDL (5) LDL (6) HDL?
(1) Yes (2) No (3) No (4) No (5) No (6) Yes
What is the function of apolipoprotein C-II?
Lipoprotein lipase cofactor