More Than One Step in the Glycolytic Pathway Is Subject

Multiple Choice

More than one step in the glycolytic pathway is subject to regulation.It might seem most efficient to regulate only the first step of a pathway to avoid buildup of intermediates and to conserve materials and energy.Why is the first step of glycolysis not the only regulated step?

A) Some sugars can enter the glycolytic pathway beyond the first step.If steps other than step one were not regulated,the breakdown of these sugars would be essentially uncontrolled.
B) Having more than one regulated step in the pathway allows for feedback inhibition.
C) Control of a single step in a reaction pathway is difficult because the concentrations of enzymes in cells are very low.It's easier to control more than one enzyme.
D) All the ATP in a cell would be depleted very quickly if only the first step of glycolysis were regulated.