Mid 2: lec 11 Flashcards
(12 cards)
sources of glycerol 3 phosphate
Recycling of the glycerol produced during lipolysis of TAG
Reduction of dihydroxyacetone phosphate (DHAP) produced during
glycolysis
Reduction of dihydroxyacetone phosphate (DHAP) produced during
glyceroneogenesis.
Liver and adipocytes sources of glycerol 3 phosphate
liver: all 3
adipocytes: do not have glycerol kinase so only use the 2 mechs that use DHAP
two tag synth pathways and where
differ in how DAG is formed
Glycerol phosphate pathway: Liver, adipose tissues and intestine
Monoacylglycerol pathway: Specific to the intestine
glycerol phosphate DAG synth pathway
glycerol 3 phosphate plus fatty acyl coa to DAG
GPAT, AGPAT, PAP1
monoacylglycerol DAG synth path
monoacylglycerol plus fatty acyl coa to DAG
MGAT
DAG to TAG
DAG plus fatty acyl coa
uses DGAT
Localization of TAG biosynthesis machinery
Endoplasmic reticulum (ER) and the mitochondria outer membran
Fate of TAGs
Storage in Lipids droplets (LDs)
-Redistribution of TAG throughout the body
Chylomicrons (intestine)
Very-Low-Density Lipoprotein (liver)
Biological functions of cholesterol
- structural component of cell membranes, particularly the
plasma membranes - constituent of lipoproteins
- precursor for bile acids and steroid hormones
location of cholesterol biosynth (organs)
mostly liver and intestine
also adrenal glands and reproductive organs
cholesterol biosynth steps liver including num_carbons
-condensation
acetyl coa (C2) to hmg-coa to mevalonate (C6) to DMAPP (C5)(isoprenoid)
hmg-coa reductase catylizes rate limiting step
-polymerisation
polymerization of isoprenoids IPP and DMAP (C5) to form farnesyl pyrophosphate (C15)
prenyltransferase
Polymerization of farnesyl pyrophosphate (C15) to
form squalene (C30)
squalene synthase
-cyclization
Cyclization of squalene to form lanosterol (C30)
Synthesis of cholesterol (C27) from lanosterol (C30)
cholesterol synth enzymes organelle location
peroxisome (pre squalene)
ER
