TCA

Question 1

Where does TCA occur?

Answer 1

In all cells with mitochondria; mitochondrial matrix

Except succinate dehydrogenase (inner membrane)

Question 2

Substrates and products for TCA

Answer 2

Substrate: Acetyl CoA
Products: CO2, GTP, NADH, FADH2

Question 3

Rate-limiting step of TCA

Answer 3

Isocitrate —> alpha ketoglutarate
Enzyme: isocitrate dehydrogenase
Products: CO2, NADH

Question 4

Enzymes that produce CO2 in the TCA pathway

Answer 4

Isocitrate dehydrogenase
Alpha-ketoglutarate dehydrogenase
(Not part of Krebs: pyruvate dehydrogenase complex)

Question 5

TCA Enzymes involved in the production of NADH:

Answer 5

Isocitrate dehydrogenase
Alpha-ketoglutarate dehydrogenase
Malate dehydrogenase
(Not part of Krebs: pyruvate dehydrogenase complex)

Question 6

TCA enzyme that produce FADH2

Answer 6

Succinate dehydrogenase

Succinate -> fumarate

Question 7

TCA enzyme that produce GTP

Answer 7

Succinate thiokinase

Succinyl CoA -> succinate

Question 8

Functions of TCA (3)

Answer 8

Provides majority of ATP for energy, gluconeogenesis from skeletons of aa, building blocks for aa and heme (succinyl CoA)