TCA cycle Flashcards
Where does glycolysis, pyruvate processing, TCA cycle and ETC happen?
glycolysis: cytoplasm
pyruvate processing & TCA cycle: mitochondrial matrix ETC: inner membrane
What is cristae?
extensions of inner membrane
layers of sac like structures.
fill inside of mitochondria.
are connected to inner membrane by short tube
under hypoxic or anaerobic, what happens to pyruvate?
fermentation into ethanol or lactate
under aerobic conditions, what happens to pyruvate?
pyruvate –> acetyl-Coa –> produces CO2 and water
5 coenzymes required for pyruvate processing?
TPP
Lipoyl lisine (lipoamide)
FAD
NAD+
CoA-SH
Pyruvate processing catalyzed by which enzyme?
Pyruvate dehydrogenase complexe
Which 3 enzymes for pyruvate processing?
Pyruvate dehydrogenase
Dihydrolipoyl transacetylase
Dihydrolipoyl dehydrogenase
Pyruvate processing regulated by what?
Feedback inhibition: if products of glycolysis or pyruvate are abundant –> PDH is phosphorylated and inhibited through change in conformation
5 steps of pyruvate processing
- decarboxylation of pyruvate to aldehyde
- oxidation of aldehyde into carboxylic acid –> electrons reduce lipoamide to form thioester
- formation of acetyl-coA
- Reoxidation of lipoamide cofactor
- Regeneration of oxidized FAD cofactor –> forms NADH
FAD with which enzyme?
Dihydrolipoyl dehydrogenase
TPP with which enzyme?
Pyruvate dehydrogenase
Lipoyl lysine with which enzyme?
Dihydrolipoyl transacetylase
NAD and CoA-SH in which steps of pyruvate processing?
NAD in step 5 + CoA-SH in step 3
Does coenzyme A stay on enzyme’s structure?
No. associate, fulfill function, dissociate
Function of Coenzyme-A?
accept and carry acetyl groups –> carries remaining carbons from glucose to TCA cycle to be further oxidized
Multiple intermediates from CAC can be used as reactants in other metabolic pathways –> name?
Anaplerotic reactions
CAC = amphibolic?
Involves both catabolism and anabolism