Question

Five molecules of pryuvate are converted into acetyl CoA and then further oxidized (to CO2) through the citric acid cycle. please answer the following quetions:

a. how many molecules of NADH (+H+), FADH2, and GTP are produced from oxidation of these 5 pyruvate molecules?

b. how many total high energy phosphate are generated (upon oxidation of NADH (+H+) and FADH2 molecules that you have indicated above)? please include in this total number the GTP produced as well; in other words, provide the total number of high enegry phosphates that are obtained from the full oxidation of the 5 pyruvate molecules to CO2.

please explain,

Answer 1

Ans. The amount of GTP, NADH, FADH2 and ATP produced from complete oxidation of 2 moles of pyruvates (one glucose produce 2 pyruvate) is tabulated below.

#A. No. of NADH produced = (8 NADH / 2 Pyruvate) x 5 Pyruvate = 20 NADH

No. of FADH₂ produced = (2 FADH₂ / 2 Pyruvate) x 5 Pyruvate = 5 FADH₂

No. of GTP produced (substrate level phosphorylation) =

(2 GTP/ 2 Pyruvate) x 5 Pyruvate = 5 GTP

#B. No. of ATP from NADH oxidation though ETC

= (2.5 ATP/ NADH) x 20 NADH = 50 ATP

No. of ATP from FADH₂ oxidation though ETC

= (1.5 ATP/ FADH₂) x 5 FADH₂ = 7.5 ATP

No. of ATP equivalents from GTP = 5 GTP = 5 ATP

# Total ATP (high energy phosphates) generated from complete oxidation of 5 pyruvate molecules = 50 ATP + 7.5 ATP + 5 ATP = 62.5 ATP