Question

Reaction #3 of glycolysis is catalyzed by phosphofructokinase and is also known as the “committed step” or "commitment step". Which of the following can be inferred from this term?
a-The reaction has a ∆G value near 0

b-The reaction is subject to regulation

c-All of the statements can be inferred

d-The reaction is reversible

Answer 1

The answer is option b.

The committed step in glycolysis is the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate by the enzyme phosphofructokinase.

• Option b(the reaction is subject to regulation) is correct because ATP molecules regulate this reaction. ATP is utilized during this process. If the amount of ATP in the cell is less, the reaction is carried out, if the amount of ATP is more, the reaction is ceased and thus regulated.
• the reaction is named as committed because once the reaction takes place it cannot be reversed i.e, it is an irreversible reaction, hence option d is incorrect.
• This step of glycolysis is not in equilibrium therefore, the delta G cannot be zero,hence option a is incorrect.