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32 Cards in this Set
- Front
- Back
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What are some of the normal function of cholesterol?
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Component of cell membranes, necessary for making bile acid, vitamin D, and steroid hormones
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What are the starting materials for cholesterol synthesis?
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Acetyl CoA, ATP, NADPH
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What are the products of cholesterol synthesis?
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Cholesterol, ADP, NADP+
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Where does cholesterol synthesis occur?
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Hepatocytes
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What is the regulatory enzmye in cholesterol synthesis?
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HMG CoA Reductase
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How is HMG CoA reductase regulated by insulin?
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high insulin/glucagon ratio increases cholesterol synthesis by signaling that ATP and acetyl CoA are avaliable for cholesterol synthesis
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When does proteolysis of HMG CoA reducatase increase?
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proteolysis of HMG CoA reductase increases as sterol levels increase
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What induces/represses sythesis of HMG CoA reductase?
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Synthesis is induced/repressed with levels of cholesterol
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How do extrahepatic cells receive cholesterol?
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From LDL from liver. Synthesis of cholesterol is not typically done by extra hepatic cells.
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How is cholesterol stored in cells?
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As a cholesterol ester
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What are some of the normal function of cholesterol?
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Component of cell membranes, necessary for making bile acid, vitamin D, and steroid hormones
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What are the starting materials for cholesterol synthesis?
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Acetyl CoA, ATP, NADPH
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What are the products of cholesterol synthesis?
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Cholesterol, ADP, NADP+
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Where does cholesterol synthesis occur?
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Hepatocytes
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What is the regulatory enzmye in cholesterol synthesis?
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HMG CoA Reductase
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T or F? HMG CoA reductase is not regulated by esterfied cholesterol.
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True
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Where is bile salt/acid synthesized?
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Hepatocytes
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What are the starting materials for bile salt/acid?
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Cholesterol, ATP, and NADPH
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What is the control step in bile salt/acid synthesis?
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7-alpha-hydroxcholesterol from cholesterol is feedback inhibited by bile salt levels
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What are the products of bile salt synthesis?
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Primary unconjugated bile salts: cholic acid and chenocholic acid
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What does conjugation of primary bile salts do?
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Makes the bile salts more soluble allowing it to act as a detergent
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What are the four primary conjugated bile salts?
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taurocholic, glycocholic,
tarurochenocholic, glycochenocholic |
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How are bile salts degraded?
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Most are reabsorbed by the body 95%, 5% are excreted in feces
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Which lipoproteins are associated with higher risk for CVD?
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LDL and TG
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Which lipoproteins are associated with lower risk for CDV?
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HDL
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Describe the structure of a lipoprotein
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Phospholipid sphere with apoproteins on surface. Inside there is TG and cholesterol.
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Relate protein/lipid ratio to the various lipoproteins
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VLDL and LDL have low protein to lipid ratios
HDL had high protein to lipid ration |
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What do chylomicrons do?
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Transport dietary lipids in fed state, NOT synthesized by liver
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Which proteins does HDL transfer to nacent chylomicrons?
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Apo E and Apo C2
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What do Apo E and Apo C2 activate repectaviely?
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Apo E activates hepatic receptors
Apo C2 activates lipoprotein lipase |
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Chylomicrons are transported to:
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Adipose and skeletal muscle where lipoprotein lipase converts TG to FA and glycerol
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What are chylomicron remenants?
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Chylomicrons minus TG
They have cholesterol and go to liver |
