Final answer:
The committed step of glycolysis is the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate by the enzyme phosphofructokinase.
Step-by-step explanation:
The committed step of glycolysis is the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate, catalyzed by the enzyme phosphofructokinase-1 (PF K-1). This reaction is crucial in regulating the glycolytic pathway. The structural formula of fructose-6-phosphate is
, and fructose-1,6-bisphosphate is
.
The enzyme PF K-1 requires ATP as a cofactor for this reaction. The committed step is highly regulated, and the phosphorylation of fructose-6-phosphate is an irreversible process, committing the substrate to further metabolism in glycolysis. This regulation ensures control over the glycolytic pathway and links cellular energy needs to metabolic activity.