Question

During the complete oxidation of one sucrose molecule, how many ATP are produced by $FAD{H}_2$ of Krebs cycle?

• A. $24$
• B. $8$
• C. $3$
• D. $4$

Answer 1

Answer: (B)

$8$

Sucrose is made up of glucose and fructose. From one molecule of glucose, 38 ATP molecules can be produced during cellular respiration. During Kreb cycle, 2 molecules of FAD are reduced to FADH${}_2$. Now 2 FADH${}_2$ produce 2 x 2 = 4 ATP molecules. Fructose is converted to fructose-6-phosphate by hexokinase enzyme. This fructose-6-phosphate then enters the glycolysis and produces same amount of ATP as glucose molecule does. Hence, it will also produce 4 ATP molecules by FADH${}_2$ of Krebs cycle. Hence, total ATP produced will be 8 molecules phosphorylation by FADH${}_2$ of Krebs cycle.

Thus, the correct answer is '8.'