Lipoproteins Flashcards
what do lipoprotein particles contain
A hydrophobic core containing esters of cholesterol and glycerol
describe the surface of lipoproteins
hydrophilic and contain phospholipids, free cholesterol and apoproteins
how are lipoproteins classified
size and density
what are the classifications of lipoproteins
VLDL
IDL
LDL
HDL
how are chylomicrons synthesized
by intestinal epithelial cells
what happens after the chylomicrons are synthesized
they are secreted into lymphatic circulation and drains into the blood at the thoratic duct
what does chylomicrons do
transports dietary triacylglycerols, lipid soluable vitamins and cholesterol around peripheral tissues
what happens to lipoprotein lipase
synthesized by tissues and secreted into circulation, where attached to endothelial cells eg adipocytes, mytocytes
what happens to the monoacylglycerol produced
cleaved into glycerol and free fatty acid by monoacylglycerol lipase in plasma
what happens to the free fatty acids and glycerol produced
taken up by tissues
what happens to the chylomicron remnant
removed from circulation by binding to LDL-like receptors on hepatocytes and receptor-meditated endocytosis
what does chylomicron do
delivers dietary cholesterol and lipid soluble vitamins to the liver
where is VLDL produced
in the liver hepatocytes from the endogenous cholesterol
what does VLDL do
moves through circulation of tissues and LDL removes TAG
exchange of TAG with cholesteryl esters in HDL
what is LDL
cholesterol rich lipoproteins
what does LDL do
delivers cholesterol to peripheral tissues such as the adrenal gland
binds to LDL receptors and internalized by receptor-meditated endocytosis
where are LDL receptors expressed
on liver hepatocytes
how does synthesis of bile acids happen
cholesterol is removed from the circulation and excretion in bile
what happens in reverse cholesterol transport
Apolipoprotein A is synthesised by liver and incorporated into VLDL
in circulation apolipoprotein A dissassociates from VLDL
as it moves through circulation, acquires cholesterol and phospholipids from membrane of cells in peripheral tissues, forming HDL
what is cholesterol esterficated by
LCAT
where is LCAT produced and secreted from
the liver
what does LCAT do
binds to apoliprotein A, so bound to HDL
what is the reaction catalysed by
cholesterol ester transfer protein
made and secreted by hepatocytes and bound to HDL
what removes TAG and phospholipids in HDL
hepatic lipase
