Question

For each molecule of glucose that enters glycolysis, how many atp molecules are gained?

a. 6
b. 4
c. 3
d. 2

Answer 1

d. 2 ATP will be gained.

The process of Glycolysis requires 2 ATP to be activated. After glycolysis, 4 new ATPs will be produced. However, as mentioned, 2 will be used, hence only 2.

Answer 2

d. 2

Step-by-step explanation:

The glycolysis is the first step in glucose degradation that generated energy for the cellular metabolism. The glycolysis has two phases: one that requires energy and other that releases energy. These phases are described in the attached image.

In the Energy-requiring phase the glucose is rearranged and are added 2 phosphate groups forming fructose-1,6-bisphosphate. This molecule is unstable, so it is divided in two phosphate-bearing three-carbon sugars. The two phosphates used in these steps come from ATP molecules, so it is needed two molecules of ATP in this first phase.

In the Energy-releasing phase each three-carbon sugar formed turn into pyruvate by a series of reactions. These reactions produce 2 ATP molecules for each three-carbon sugar. And since this phase occurs twice, in total, there are produced 4 ATP molecules.

The general reaction is:

Glucose + 2ATP + 2ADP + 2Pi + 2NAD+ ---> 2 pyruvate + 4 ATP + 2 NADH + H2O

Or

Glucose + 2ADP + 2Pi + 2NAD+ ---> 2 pyruvate + 2 ATP + 2 NADH + H2O

So, this process produces 2 ATP molecules.