TCA cycle

Question 1

TCA cycle accounts for _____ of energy derived from fuel oxidation

Answer 1

> 2/3

Question 2

Where does the TCA cycle take place?

Answer 2

Mitochondrial matrix

Question 3

What is the direct substrate of the TCA cycle?

Answer 3

Acetyl-CoA

Question 4

How many NADH, FAD and GTP does the TCA cycle produce?

Answer 4

3 NADH, 1 FAD, and 1 GTP

= 10 phosphate bonds / acetyl group

Question 5

What is the delta G for the TCA cycle?

Answer 5

-13 kcal

Question 6

Which enzyme in the TCA cycle is not in the mitochondria matrix?

Answer 6

Succinate dehydrogenase

Question 7

Which enzyme connects the TCA cycle w/ ETC?

Answer 7

Succinate dehydrogenase

Question 8

Which enzymes provide the ability for the TCA cycle to keep on going based off of delta G?

Answer 8

Citrate synthase, isocitrate dehydrogenase, and α-ketoglutarate dehydrogenase

Question 9

Which type of fuel appears to contain the highest density of energy?

Answer 9

Fatty acids, which contain the greatest number of C2 units mimicking acetyl-CoA

Question 10

Which type of fuel is more readily oxidized?

Answer 10

Pyruvate, acetoacetate, ethanol, etc which are structurally close to acetyl-CoA

Question 11

What enters the TCA cycle?

Answer 11

Acetyl-CoA, NAD+, FAD, H2O, GDP, Pi

Question 12

What comes out the TCA cycle?

Answer 12

CoASH, CO2, NADH + H, FAD(2H), GTP

Question 13

How is the energy from -SCoA used in each reaction?

Answer 13

In the first reaction, energy is used to push the reaction forward (heat up the reaction)

In the second reaction, it is used to form high energy bonds in GTP

Question 14

What factors will increase the TCA rate?

Answer 14

ADP and Calcium

Question 15

What factors will inhibit the TCA rate?

Answer 15

NADH and Citrate