TCA cycle Flashcards
What is the purpose of the TCA cycle?
-generates NADH for the e- transport chain
(Oxidizing acetyl CoA so the electron carriers can be reduced.)
FADH2 is fed directly into the e-transport chian in complex2
-ATP is generated via substrate level phosphorylation
Intermediates formed in the TCA pathway are fed into biosynthetic pathways
Which steps are the irreversible, large negative delta G?
citrate synthase
isocitrate dehydrogenase, alpha ketoglutarate dehydrogenase complex
Why add the CoA cofactor to acetate?
you want to make a thioester intermediate, a high energy bind, drives the synthesis, oxaloacetate is naturally very low in the cell, and this very negative delta G drives the rxn forward
Which steps in the TCA cycle produce CO2?
isocitrate dehydrogenase
alphaketoglutarate DH
Which steps in the TCA cycle produce NADH?
isocitrate DH
alpha-ketoglutarate DH
malate DH
Which steps in the TCA cycle produce GTP/ATP?
succinyl CoA (succinyl CoA synthetase) succinate
How do you switch GTP to ATP?
nucleoside diphosphate kinase
Which step makes FADH2?
succinate DH (directly linked to complex 2 of electron transprt chain)
How many CO2 from two full turns of the TCA?
4
How many NADH from two full turns?
6
How many FADH from two full turns?
2
How many GTP/ATP from two full turns?
2
How many NADH from glycolysis?
2
How many ATP from glycolysis?
4
How many acetyl-CoA from PDH?
2
How many NADH from PDH?
2
Which cofactors are involved in the pyruvate dehydrogenase complex reaction? Which enzyme complex is each cofactor located? What is the role of each cofactor?
NADH, FADH2, CoA
NADH - isocitrate DH, alpha KTG DH, malate DH
FADH2 - succinate DH
CoA - citrate synthase, alpha ketoglutarate DH
Where is the hydroxyethel transferred to lipoic acid?
interface of E1, E2
What really important thing happens at E2?
acetyl group is transferred to CoA, forming Acetyl CoA
Which are the regulated, large -delta G steps of TCA?
citrate synthase, isocitrate DH, alpha KTG DH
Which step produces GTP? Why is the production of GTP equivalent to the production of ATP?
succinyl CoA synthetase, nucleoside diphosphate kinase
