november 10 Flashcards
how do adipose cells mkae glycerol 3 phosphate
they dont have glycerol kinase so they make DHAP using glyceroneogenesis
where does glyceroneogenesis occur
in adipose tissue and liver
glyceoneogenesis and gluconeogenesis
contains some of the same steps, it converts pyruvate to DHAP instead of maknig glucose so it is just a condensed version in liver and adipose.
what enzyme makes Glycerol 3 phosphate from DHAP
glycerol 3 phosphate dehydrogenase
what stimulates triacylglycerol sytnehsis
insulin
what does lack of insulin lead to
increased lipolysis
increased fatty acid oxidation and ketone body formation
failure to synthesize FA
what is not present in adipose tissue
glycerol kinase
phospholipid structure
uses a glycerol backbone with 2 FA and one phosphate that is linked to a head group
R1 of phospholipids
almost always saturated FA
R2 of phospholipids
almost always unsaturated
what plays a role in being an integral compoent of cell membranes, storage of FA, and signalling molecules wihtin cells
phospholipids
what does phospholipid synthesis begin with
phosphatidic acid or diacylglycerol
synthesis of phospholipids step by step
attatch head group which has OH to C3 OH leading to a new phosphohead group created when phosphoric acid condences wit these two alcohols
elimination of 2 water molecules
what does the catabolism of phospholipids include
the hydrolysis of FA or head groups by a group of enzymes known as phospholipases (PLase)
what are the phospholipases
A1, A2, C, D
what do PLase do
essential for providing several critical molecules involved in the regulation of various cell activities
what do PLase A1, A2 do
liberate a single FA from PL and generate a lysophospholipid (PC to LPC)
what contains PLaseA1 and PLaseA2
toxic snake venoms that cause cell membrane damage
what phospholipase do mammals use
A2
how do mammals use A2
release arachidonic acid (20:4n-6) FROM THE SN-2 position of PLs
the released arachidonic acid is rapidly enzymatically modified to produce eicosanoids
what do eicosanoids do
potent lipid signaling molecules involved in regulating many physiological events including reproduction, inflamation, pain, fever, blood pressure
what does omega 3 FA do
inhibit the production of omega 6 FA dervied from eicosanoids (omega 6 are inglamatory and omega 3 are anti inflamatory(
what does PLase C do
liberates phosphoheadgroup (phosphocholine) and diacylglycerol from PL
diacyl glycerol liberated by PLaseC functions as a potent intracellular signalling molecules that regulate Ca2+ concentration
what does PLaseD do
converts a phoshpatidylcholine, phoshpatidyl serine, phosphatidyl ehtanolamine or phosphatidylinositol into phosphatidi acid
the acid produced through this route can be used towards the synthesis of triacylglycerol
