Lipid Metabolism Flashcards
What is the role of fatty acid oxidation
responsible for providing energy to cells when glucose is low
excess ______ is converted to fatty acids that can be stored or exported as triaglycerols
acetyl-CoA
What is ketogenesis
production of ketone bodies by the breakdown of fatty acids and ketogenic amino acids
ketogenesis supplies energy to certain organs (particulairly the brain) under what circumstances
starvation or fasting
Most humans have enough triacylglycerols in adipose to last __ months in starvation
3
what are the key enzymes in fatty acid oxidation and synthesis
fatty acyl-CoA synthease, carnitine acetyltransferase I, acetyl-CoA carboxylase, fatty acid synthase
what does fatty acyl-CoA synthease do
catalyzes “priming” reaction in metabolism
what does carnitine acetyletransferase I do
catalyzes the commitment step in oxidation
what does acteyl-CoA carboxylase do
catalyzes the commitment step in synthesis
What does fatty acid synthase do
catalyzes a series of reactions that adds C2 units to a growing fatty acid chain
the carnitine transport cycle translocates ____ ___ across the inner mitochrondrial membrnae
fatty acids
The complete oxidation of palmitoyl-CoA requires ____ cycles of the __ step beta cycle to yield _acetyl-CoA, _FADH2 and _NADH
requires seven cycles of the four step beta cycle to yield 8acetyl-CoA, 7FADH2 and 7NADH
Ketogenesis slavages _____ from liver mitochondria and converts it to _____ and _____
acetyl-CoA and converts it to aceoacetate and D-beta hydroxybutyrate
ketone bodies in the liver are exported to the ____
blood
oxaloacetate is used to make ______ for gluconeogenic pathway, therefore increasing acetyl-CoA lelvels
phophophenol pyruvate
What are the four steps inthe fatty acid synthase complex
condensation, reduction, dehydration, reduction
What are the two cycles in the fatty acid sythase compolex
- priming reaction where acetyl group attaches to sulfhydryl group of a Cys residue
- malonyl group from malonyl-CoA attached to ACP by MAT subunit
what are the three biochemical reactions that control the flux of fatty acid synthesis and degredation
1-citrate activation of acteyl-CoA carboxylase
2-inhibition of canitine acyltransferase by malonyl-CoA
3-inhibition of acetyl-CoA carboxylase by fatty acyl-CoA
cholesterol is an essential lipid constituant for _______
cell membranes
cholesterol is a precursor of ____ hormones and of ___ ___
steroid hormones and bile acids
high plasma cholesterol promotes ___________
artherosclerosis
lipoprotein particles contain what?
cholesterol ester, tricylglycerols
when do artheroscleroic plaques form
when injury occurs to the endothelial lining, allowing LDL particles to invade and initiate an immune response
what are artheroscleroic plaques made up of
cholesterol and fat deposits, microphage foam cells and fibrous material
What are statin drugs
HMG-CoA reductase inhibitors that lower serum LDL levels
What is Ezetimbe
blocks the import of dietary cholesterold by inhibiting the transport of NPC1L1 protein from small intestine
Bile acid binding resins are used for what?
to lower serum cholesterol levels
where does beta oxidation of fatty acids occur
in the mitochondrial matrix
what are the four cyclic reactions in beta oxidation of fatty acids
dehydration, hydration, oxidation and thyolysis
what happens in each cycle of beta oxidation
a fatty acid is progressively shorted by 2 carbons as its oxidized and energy is captured by NADH and FADH2
at the end of each beta oxidation cycle what is your product
acetyl-CoA
if an odd number of carbons are left what is your product of beta oxidation cycle
propoionyl-CoA
What is the ATP yeild of palmitoyl CoA per NADH and FADH2
2.5ATP per NADH, 1.5 ATP per FADH2
What is the overall ATP yeild per palmitoyl CoA
108 ATP
