Question

Question 4 Q . OH ATP OH POH ОН Fructose 6-phosphate Fructose 1.6-bisphosphate Figure 1. Reaction catalyzed by phosphofructokinase (PFK) during glycolysis Phosphofructokinase (PFK) is an enzyme that catalyzes the conversion of fructose 6- phosphate to fructose 1,6-bisphosphate during glycolysis, as represented in Figure 1. PFK can be allosterically inhibited by ATP at high concentrations. Which of the following is the benefit of regulating glycolysis by the concentration of ATP? Glycolysis proceeds when the intracellular concentration of ATP is low, which provides ATR to drive cellular reactions. Highlight Glycolysis proceeds when the intracellular concentration of ATP is high and the cell stores ATP for future use. Glycolysis is inhibited when the intracellular concentration of ATP is low because PFK requires ATP as a substrate for the reaction it catalyzes. Glycolysis is inhibited when the intracellular concentration of ATP is high because ATP will compete with fructose 1,6-bisphosphate for binding to the active site on the enzyme A

Answer 1

Question 4

Ans : Option D

$\odot$ Glycolysis is inhibited when the intracellular concentration of ATP is high because ATP will compete with fructose 1,6-biphosphate for binding to the active site on the enzyme.

Reason : A high level of ATP inhibits the enzyme by decreasing its affinity for fructose 6-phosphate. ATP obtain this effect by binding to a specific regulatory site that is distinct from the catalytic site. This means activity of enzyme increases when ATP is lowered. Thus we can say that glycolysis is stimulated as the energy charge falls and glycolysis is inhibited as the energy charge rises.