Question

Select the glycolytic enzymes that require ATP.

a) Hexokinase
b) Phosphofructokinase
c) Pyruvate kinase
d) Enolase

Answer 1

In glycolysis, hexokinase and phosphofructokinase are the enzymes that require ATP. Hexokinase uses ATP to phosphorylate glucose, while phosphofructokinase uses another ATP to phosphorylate fructose-6-phosphate.

Step-by-step explanation:

The glycolytic enzymes that require ATP are hexokinase and phosphofructokinase. During glycolysis, glucose is first phosphorylated by hexokinase using ATP to form glucose-6-phosphate. This first step consumes one ATP molecule, effectively trapping the glucose within the cell to facilitate further metabolism. Additionally, phosphofructokinase catalyzes the phosphorylation of fructose-6-phosphate, using another molecule of ATP, resulting in the formation of fructose-1,6-bisphosphate. This step is a committed and highly regulated point within the glycolysis pathway.

Enzymes Utilizing ATP in Glycolysis

1. Hexokinase: Phosphorylates glucose using ATP to produce glucose-6-phosphate.
2. Phosphofructokinase: Phosphorylates fructose-6-phosphate using ATP to produce fructose-1,6-bisphosphate.