Question

Why is the activity of Phosphofructokinase (PFK-1) high at moderate concentrations of ATP and low at high concentrations of ATP?

		When there is a lot of ATP, it gets consumed more rapidly in other processes, which decreases the ability of PFK-1 to use it.
		ATP is a competitive inhibitor of PFK-1.
		At high concentrations ATP is an allosteric inhibitor of PFK-1.
		ATP phosphorylates PFK-1, inactivating it.

What is required for fermentation?

		O2
		ATP
		NADH
		Pyruvate
		Both NADH and pyruvate

Answer 1

I. At high concentration, ATP molecule can bind at phosphofructokinase's regulatory site instead of binding to the active site of enzyme, which changes the shape of the enzyme in a way that results in dramatic fall in reaction rate at the active site. ATP acts as an allosteric inhibitor of PFK-1.

CORRECT OPTION IS " At high concentrations ATP is an allosteric inhibitor of PFK-1.

II. Both reduced NADH and pyruvate formed in glycolysis is required during fermentation. NADH reduces pyruvate and pyruvate is reduced into lactate (or ethanol).

CORRECT OPTION IS " Both NADH and pyruvate"