Question

After glycolysis has been completed (and before pyruvate is processed) most of the usable energy from the original glucose molecule is contained in ___ molecules.

a. Acetyl-Coa

b. ATP

c. NADH and FADH2

d. CO2

e. pyruvate

Answer 1

Ans:

b. ATP

Explanation: The energy obtained from conversion of glucose to pyruvate is 2 ATP and 2 NADH. The ATP molecules are produced by direct transfer of phosphate moiety from a substrate to ADP in substrate-level phosphorylation. The high energy stored in ATP is readily usable for other process. The NADH is not readily usable because it first reoxidize to produce 2.5 ATP molecules and then it is used. Acetyl-CoA , FADH2 and CO2 are produced in pyruvate decarboxylation and citric acid cycle after pyruvate is processed. Pyruvate is a acid, not a usable energy stored molecule.