Metabolism 9 Flashcards
What are lipoproteins?
Used for transporting lipids in plasma. Composed of apolipoproteins and lipids
Rank the following in terms of % protein composition (greatest to least):
HDL, LDL, VLDLs, IDLs, chylomicrons
HDL > LDL >IDL > VLDL > chylomicrons
Rank the following in terms of % lipid composition (greatest to least):
HDL, LDL, VLDLs, IDLs, chylomicrons
Chylomicrons > VLDL >IDL >LDL > HDL
What is the general structure of plasma lipoproteins?
Amphipathic Phospholipid micelle with cholesterol embedded and apoproteins
Core made of TAGs, Cholesterol Esters and nonpolar lipids
What is the function of chylomicrons?
Transport dietary TAG from intestines to adipose tissue and other tissues.
What is the main lipid of chylomicron and its apoprotein?
TAG
B-48 (A,C,E)
What is the function of chylomicron remnant?
Deliver remaining dietary TAG to liver. Exchanges TAG for cholesterol ester from HDL and transfers it to liver as well
What lipid and apoprotein make up the chylomicron remnant?
TAG
B-48 (A,C,E)
What lipid and apoprotein make up the VLDL? Where is it formed?
Lipid: TAG
Apoprotein: B-100 (C,E)
Formed in liver
What lipid and apoprotein make up IDL? Where is it formed?
Lipid: TAG and cholesterol
Apoprotein: B-100 (C,E)
Formed via processing of VLDL in circulation (VLDL remnant)
What lipid and apoprotein make up LDL? Where is it formed?
Lipid: Cholesterol
Apoprotein: B-100
Formed via processing of IDL in circulation
What is the function of VLDL?
Transport endogenously synthesized TAG to adipose tissue and heart/skelteal muscle
Exchanges TAG for CE from HDL
What is the function of IDL?
Deliver remaining TAG and cholesterol to the liver
Exchanges TAG for CE from HDL and delievers it to liver
What is the function of LDL?
Deliver cholesterol to the liver and other cells (steroidgenic cells etc)
What is considered “bad cholesterol”?
LDL
What is considered “good cholesterol”?
HDL
What lipid and apoprotein make up HDL? Where is it formed?
Lipid: cholesterol
Apoprotein: A, C, E
Formed in the liver and intestines
What is the function of HDL?
Accepts cholesterol from peripheral cells -> esterifies it -> transports CEs to liver
Exchange CE for TAG in VLDL, IDL, and chylomicron remnants
Atheroprotective via enzymes (Paroxonase) to protect cells against oxidative damage and inhibit LDL oxidation
Resevoir for circulating apoproteins A, C, and E that can be transported to other apoproteins
Chylomicrons transport what kind of lipids?
Dietary exogenous lipids
VLDL, IDL, LDL transport what kind of lipids?
Synthesized endogenous lipids