Mitochondrial Energy Production: TCA Flashcards
TCA cycle
occurs in mitochondria
Where do substrates for the TCA cycle come from?
Acetyl CoA derived from glycolytic pyruvate, b-oxidation, succinyl-CoA derived from odd chain b-oxidation, amino acid catabolism
how does pyruvate get into mitochondria?
mitochondrial pyruvate carrier protein
where does oxaloacetate come from for TCA cycle if not already present?
anaplerotic rxns generate TCA intmdts from glycolytic pw; propionyl-CoA can be source for oxaloacetate generation; amino acid catabolism
what does last half of TCA cycle look like?
beta-oxidation
thiamine
water soluble; cleavage of c-c bond
riboflavin (B2)
water soluble vitamin; flavin mononucleotide; oxidation-reduction
niacin
water soluble vitamin; NADP and NAD, Oxidation reduction
vitamin B6
pyridoxal phosphate; water soluble vitamin; coenzyme of enzymes in Aa metabolism
folate
tetrahydrofolate (THF); 1 carbon transfer; water soluble vitamin;
vitamin b12
methylcobalamin and adenosylcobalamin; coenzyme for methionine synthase and methylmalonyl CoA mutase; water soluble vitamin;
what happens to excess fat:
stored as fat; cannot be converted to sugar because there is no net flux of carbon from acetyl-coa to PEP
why can fat not be converted to sugar?
because oxaloacetate is a catalyst in the TCA cycle and it is a substrate in the gluconeogenesis (PEP) pathway; no carbons are left over with TCA cycle
PEP
phosphoenol pyruvate; intermediate in gluconeogenesis
where does electron transport chain occur?
inner membrane of mitochondria
