Test 3

Question 1

Explain the difference in efficiency (ATP yield) of aerobic and anaerobic pathways.

Answer 1

The theoretical yields for 1 molecule of glucose is of 36 to 38 ATP for aerobic respiration and of 2 to 36 ATP for anaerobic respiration.

Question 2

What are the 3 reasons for the difference between the actual yield and the theoretical yields in respiratory pathways?

Answer 2

1) NADH transport costs 1 ATP/NADH (1 glucose = 2 ATP)
2) IMM is leaking = loss of protons
3) Pyruvate transport = secondary active transport (proton pumps use H+ so those are not available for chemiosmosis)

IMM : Inner mitochondrial membrane

Question 3

For each NADH that is oxidized (for each pair of electrons that travels down the ETC) what is pumped in the inter membrane space?

Answer 3

10 protons (H+)

Question 4

How many protons are needed to flow back through the ATP syntase for the synthesis of 1 ATP?

Answer 4

Somewhere between 3 and 4 H+

Question 5

Overall, what is the NADH:ATP ratio for every NADH oxidized by the ETC?

Answer 5

Between 2.5 and 3.3 molecules of ATP.