Lipids II Flashcards
citrate cleavage pathway
how excess acetyl-CoA is export4ed from teh mitochondria
how does citrate get through the innermitochondrial membrane
tricarbozyl acid transport
what happens with citrate gets into the cytopalsm
ATP citrate lyase separates citrate into OAA and acetyl CoA
how do you get OAA into the mitochondrial matrix
malate dehydrogeanse and malic enzyme convert into pyruvate and CO2
what happens when OAA gets converted into pyruvate and CO2
turns NADH into NADPH
what do high cytoplasmic citrate conc indicate
CAC is not able to process all the actyl CoA
what does high cytoplasmic citrate trigger
glycolysis slows down
FA synthesis ramps up
what is the committed step of malonyl CoA
Acetyl-CoA caarboxylase
how does FA synthesis start
transfer of acetyl group for acetyl CoA to acyl carrie rprotein on FA synthase
what happens to the acetyl group on FA synthase
moves from A site to C site
what happens to the empy A site
malonyl group transfered ther
what happens to the acetyl group on the C site
transferred to alpha carbon of teh maloyn group on A site
CO32 released
what happens to the acetyl group after its on the alpha carbon
keto group on beta carbon is removed, saturated fatty acids transferred back to C site
how many carbons is palmitic acid
16
what do you need to make 1 molecule of pamitic acid
8 acetyl CoA
7 ATP
14 NADPH
what happens after palmitic acid has been released from FA synthase
linked to CoA and modified by elongation and desautration
where does elongation of FA take place
ER or mitochondria
what happens to FA in ER
elongated in process similiar to FA syntehsis
what happens to FA in mitochondria
FA elongaed in process simliar to reverse beta oxidation
what end to elongation of FA take plac
carboxyl end
where does destuartion of FA occur
ER
what does desaturation of FA require
p450 monoxygenase system
whawt carbon can you not make a double bond past
9
what are important features of lipid droplets
they are surrounded by phospholipid monolayer
covered with structural proetins
bind to enzymes required for TAG synthesis and degration
TAGs
triacyglycerols
what are the msot active tissues in fat synthesis
adipose, liver, muscles
synthesis of TAGs requires what
glycerol
how do activate FA
bind to COenzyme A using ATP
what is the committed step of fat synthesis
acyl-COA dicyglycerol acltransferases (DGAT)
what are the 3 signals that regulate fat synthesis and degration
nutritional status
engery status
presence of lipids
how does insulin affect FA synthesis
induces expression of actyl-CoA carboxylase, FA synthase
both fatty acid synthase and actyl CoA carboylase is activated by what
citrate
what happens to FA and TAG synthesis in the fasting state
decrease
how does cAMP affect FA synthesis
activates PKA, which inactivates acetyl-CoA carboxylase
what do high levels of AMP activate
AMPK, which inactivates acetyl-CoA carboxylase
how does malonyl-CoA affect FA degration
inhibits
what is the main regulated step of FA degration
import of FA into mitochondrion by CPT1
what inhibits CPT1
maylonyl CoA
what do free fatty acids stimulate
FA degration an dketogensis
what do fatty acids bind to
PPARalpha
PPARalpha
transcription activater binds to PPRE in promotre region of genes for fatty acid oxidation and ketogensis
really of free fatty acids from adipose tissue is regulated by waht
glucagon/insulin ration
high glucagon/insulin ration in fasting state leas to what
release of FA from adipose tissue
how does glucagon leads to realse of FA from adipose tissue
activation of PKA via cAMP
PKA activates perilipin and hormone sensitive lipiase
lipase cleaves storage fat, reeases free FAs into circulation
function of hormone senstive lipase
turns TAG into FFA and glycerol
