Answer:
d. 2
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.
