Bioenergetics and TCA cycle Flashcards
What is an example of a biologically common coupled reaction?
ADP to ATP
What vitamin does thiamine come from?
Vitamin B1
Pyruvate dehydrogenase complex has a very similar structure to what TCA cycle enzyme?
alpha-ketoglutarate dehydrogenase
What three cofactors do a-keto dehydrogenase and PDC require?
Thiamine pyrophosphate
lipoic acid (lipoamide)
FAD
What complex of PDC/a-keto dehydro is thiamine the cofactor for?
E1
What complex of PDC/a-keto dehydro is lipoic acid (lipoamide) the cofactor for?
E2
What complex of PDC/a-keto dehydro is FAD (lipoamide) the cofactor for?
E3
What is an irreversible inhibitor of dihydrolipoamide in PDC complex E3?
Arsenite (10x more toxic) and arsentate
High citrate concentrations indicates the presence of a lot of acetyl CoA, which stimulates the formation of what?
Fatty acids
What is dry beriberi?
Low thiamine (B1) + peripheral neuropathy + impaired reflex functions
What is wet beriberi?
Low thiamine (B1) + cardiovascular disease
Alcohol abuse inhibits the uptake of what?
thiamine
Can acetyl-CoA cross back into the cytoplasm?
No, it must first be changed to citrate
What does pyruvate carboxylase do?
Uses ATP to generate oxaloacetate from pyruvate to keep the TCA cycle running.
What happens in the TCA cycle when there is too much Acetyl CoA?
It is exported as citrate
What are pathways or reactions that replenish the TCA cycle intermediates?
Anaplerotic Pathways
How much ATP is each NADH worth for the ETC?
2.5 ATP
How much ATP is each FADH2 worth for the ETC?
1.5 ATP
How much ATP potential do you get from the TCA cycle including the GTP generated?
10 potential ATP
