Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

(EOC Q20) What is the ATP yield when dihydroxyacetone phosphate is completely ox

ID: 181019 • Letter: #

Question

(EOC Q20) What is the ATP yield when dihydroxyacetone phosphate is completely oxidized to CO2 by a mammalian liver cell homogenate? Assume that glycolysis, the citric acid cycle, and oxidative phosphorylation are fully active. (Hint: what NADH transport system will be preferred in the liver?)

(EOC Q20) What is the ATP yield when dihydroxyacetone phosphate is completely oxidized to CO2 by a mammalian liver cell homogenate? Assume that glycolysis, the citric acid cycle, and oxidative phosphorylation are fully active. (Hint: what NADH transport system will be preferred in the liver?)

17 16 14.5 13.5 12

Explanation / Answer

Dihydroxy Acetone Phosphate underges 5 steps to form Pyruvate marking the end of glycolysis.

As a result 1 NADH and 2 ATPs are formed.

Pyruvate undergoes oxidative decarboxyllation and forms Acetyl Co A resulting in the formation of 1 NADH.

Acetyl Co A is completely converted to Carbon dioxide througj Kreb's Cycle which yeilds 3 NADH, 1 FADH2 and 1GTP(ATP euivalent).

By now we have a total of 5 NADH, 1 FADH2 and 3 ATPs.

Each NADH produces 2.5 ATP through oxidative phosphorylation. Similarly, each FADH2 will produce 1.5 ATP.

5NADH X 2.5 ATP = 12.5 ATPs

1FADH2 X 1.5 ATP = 1.5 ATP

2 ATP

1 GTP(ATP)

So, on completely oxidising 1 molecule of Dihydroxy Acetonephosphate to Carbon dioxide will yield 17 ATPs.

First option is correct.