(Cell) Kreb's/Citric Acid Cycle (CAC)

Question 1

Step 1

Answer 1

Acetyl CoA adds its two-carbon acetyl group to oxaloacetate, producing citrate

Question 2

Step 2

Answer 2

Citrate is converted to its isomer isocitrate by removal of one water molecule and addition of another

Question 3

Step 3

Answer 3

Isocitrate is oxidized, reducing NAD+ to NADH. Then the resulting compound loses a CO2 molecule, forming alpha-Ketoglutarate

Question 4

Step 4

Answer 4

Another CO2 is lost, and the resulting compound is oxidized reducing NAD+ to NADH. The remaining molecule is then attached to coenzyme A by an unstable bond, forming succinyl CoA

Question 5

Step 5

Answer 5

CoA is displaced by a phosphate group, which is transferred to GDP, forming GTP, a molecule with functions similar to ATP that, in some cases, is used to generate ATP. Forms Succinate

Question 6

Step 6

Answer 6

Two hydrogens are transferred to FAD, forming FADH2 and oxidizing succinate, forming fumarate

Question 7

Step 7

Answer 7

Addition of water molecule rearranges bonds in the substrate, forming malate

Question 8

Step 8

Answer 8

The substrate is oxidized reducing NAD+ to NADH and regenerating oxaloacetate