Citric Acid Cycle

Question 1

What is the purpose of the Citric Acid Cycle?

Answer 1

To produce reduced coenzymes: NADH and FADH2 for ETC

Question 2

Where does the Citric Acid Cycle occur?

Answer 2

Matrix, transports NADH and FADH2 to inner mito membrane

Question 3

Citric Acid Cycle Stage 1

Answer 3

• From addition of Acetyl CoA to Succinyl CoA
• 2-C atoms have entered the cycle
• 2-C atoms have been oxidized to CO2
• The electrons from the oxidations were captured in 2 molecules of NADH

Question 4

Citric Acid Cycle Stage 2

Answer 4

• From production of succinate to oxaloacetate
• Regenerates oxaloactate
• Harvests energy-rich electrons

Question 5

Succinate dehydrogenase is in association with the

Answer 5

ETC (the link between the CAC and ATP formation)

Question 6

FADH2 produced by the oxidation of

Answer 6

succinate, does not dissociate from the enzyme

Question 7

Succinate dehydrogenase transfers two electrons directly from

Answer 7

FADH2 to coenzyme Q

Question 8

What are the 3 points of regulation for the CAC?

Answer 8

1) Pyruvate dehydrogenase
2) Isocitrate dehydrogenase
3) alpha-ketoglutarate dehydrogenase (MAIN ONE)

Question 9

Citrate is a precursor for

Answer 9

Fatty acids, sterols

Question 10

Alpha-ketoglutarate is a precursor for:

Answer 10

Purines (A, G)

Question 11

Succinyl CoA is a precursor for:

Answer 11

Porphyrins, heme, chlorophyll

Question 12

Oxaloacetate is a precursor for:

Answer 12

Glucose

Aspartate -> other amino acids, purines, pyrimidines

Question 13

Dual job of the citric acid cycle is:

Answer 13

Generating biological energy and building blocks for biosynthetic reactions

Question 14

If any CAC intermediates are drawn off for biosynthesis they:

Answer 14

must be replenished