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Cards In This Set
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Which types of cells are able to contribute TG-containing lipoproteins to the circulation in significant amounts?
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Intestinal mucosal cells and hepatocytes
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How do intestinal mucosal cells secrete TGs? how do hepatocytes?
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Mucosal cells secrete CMs and hepatocytes secrete VLDLs; lesser amounts of TG in HDL also secreted by both cell types
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How are the TG, CH, CE, and PL components of VLDL derived?
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De novo biosynthesis and from degradation of CM remnants
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Why can TG from VLDL provide adipocytes with a different FA composition than the dietary TG in CMs?
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The liver can reassemble the TGs and alter their FA composition
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T/F - VLDLs have are SMALLER than CMs, have a LOWER lipid/protein ratio, and have a HIGHER density than CMs
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T
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What does plasma look like when it contains a lot of VLDL or CMs? how can you tell which of the two a plasma sample contains?
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Both make plasma look creamy - VLDL will not separate to form a creamy layer and CM will
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Which integral aprotein is present in VLDLs? In CMs?
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VLDL - ApoB100
CM - ApoB48
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What is the function of the addition of Apo-C (from circulating HDL) and Apo-E to nascent VLDLs?
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Apo-C - effective substrates for LPL; Apo-E - effective substrates for clearance by liver
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Where is most uptake of VLDL happening during the fed state? in starvation?
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Fed state - adipose tissue; starved state - aerobic muscle fibers (ex. cardiac m.)
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How does the circulating half-life of VLDLs compare to that of CMs?
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VLDLs have longer half-life (2-4 hours)
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What are VLDL remnants called? what are the 2 possible fates of these molecules?
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IDLs - clearance by liver or conversion to LDL
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What enzyme is needed for the conversion of IDL to LDL?
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Hepatic lipase on sinusoidal surfaces of liver
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Does LDL contain Apo-E and Apo-B100?
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Only Apo-B100, Apo-E is returned to HDLs when IDL is converted to LDL
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Which 2 molecules are involved in the recognition and binding of LDL receptors to IDL?
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Apo-B100 and Apo-E
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Why does IDL have a more rapid uptake by hepatic LDL receptors than LDL?
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LDL only contains Apo-B100 (no Apo-E, which binds more tightly to LDL receptors)
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