Citric Acid Cycle Overview

Question 1

What is the ultimate electron accepter in aerobic oxidation?

Answer 1

O2

Question 2

What are other names for the Citric Acid Cycle?

Answer 2

Krebs Cycle or Tricarboxylic Acid (TCA) Cycle

Question 3

What are the products of one complete cycle of the TCA cycle?

Answer 3

1) 2 CO2
2) 3 NADH
3) 1 FADH2
4) 1 high energy compound (GTP or ATP)

Question 4

What is often considered the central hub of all of metabolism? Why

Answer 4

The TCA Cycle. Because it is not merely an extension of glycolysis; it is the central pathway for recovering energy from carbs, fatty acids, and amino acids that have been broken down to Acetyl CoA.

Question 5

What is the net reaction of the TCA cycle?

Answer 5

3 NAD+ + FAD + GDP + Pi + acetyl-CoA&raquo_space;» 3 NADH + FADH2 + GTP + CoA + 2 CO2

Question 6

What compound is consumed in the first step of the TCA cycle and regenerated in the final step of the cycle?

Answer 6

Oxaloacetate

Question 7

Where does the TCA cycle take place in eukaryotes?

Answer 7

Mitochondria

Question 8

True or false: The carbon atoms of Acetyl-CoA are the same ones that leave the cycle as CO2?

Answer 8

False

Question 9

From which starting molecule does the carbon in the CO2 generated by the first step of the TCA cycle come from?

Answer 9

Oxaloacetate

Question 10

How many electron pair transfers does the oxidation of acetyl-CoA to 2 CO2 require? Where do the transfers occur? How many ATP are eventually formed from these electron pairs when they are transferred to O2.

Answer 10

4; 3 come from reduction of 3 NAD+ to 3 NADH; 1 comes from reduction of FAD to FADH; 9 ATP are generated from them.

Question 11

What are the two parts of cellular respiration?

Answer 11

1) TCA Cycle

2) Oxidative Phosphorylation

Question 12

What is the primary catabolic function of the TCA Cycle?

Answer 12

Generation of NADH and FADH2 by the oxidation of acetyl CoA