Question

How many phosphorylation reactions occur for formation of fructose 1,6 biphosphate during the preparatory phase of glycolysis?

• A. One
• B. Two
• C. Three
• D. Four

Hint:

Glycolysis investment phase uses 2 ATP → both in phosphorylation steps.

Answer 1

The Correct Option is B

Concept:
Glycolysis consists of a preparatory (investment) phase where ATP is consumed to phosphorylate glucose.

Step 1: Understand phosphorylation steps. During formation of fructose-1,6-bisphosphate:
• Glucose $\rightarrow$ Glucose-6-phosphate (1 ATP used)
• Fructose-6-phosphate $\rightarrow$ Fructose-1,6-bisphosphate (1 ATP used)

Step 2: Count phosphorylation reactions. \[ \text{Total phosphorylation steps} = 2 \]

Step 3: Conclusion. \[ \text{Two phosphorylation reactions occur} \]