Conversion of fructose-6 phosphate to fructose-1-6-bisphosphate in respiration requires

Options

A. Hexokinase
B. Enolase
C. Phosphofructokinase
D. Pyruvate kinase

Answer

To determine what is required for the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate during respiration, we can analyze the options provided.

### Step-by-Step Solution:

1. **Understanding the Reaction**:
- The conversion of fructose-6-phosphate to fructose-1,6-bisphosphate is a key step in the glycolytic pathway, which is part of cellular respiration.

2. **Identifying the Enzymes**:
- We have four options: hexokinase, enolase, phosphofructokinase, and pyruvate kinase. We need to identify which enzyme catalyzes the specific reaction in question.

3. **Analyzing Each Option**:
- **Hexokinase**: This enzyme catalyzes the phosphorylation of glucose to glucose-6-phosphate. It does not act on fructose-6-phosphate, so this option is incorrect.
- **Enolase**: This enzyme is involved in the conversion of 2-phosphoglycerate to phosphoenolpyruvate in glycolysis. It does not catalyze the reaction we are interested in, making this option incorrect.
- **Phosphofructokinase (PFK)**: This enzyme specifically catalyzes the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate. This is the correct enzyme for the reaction in question.
- **Pyruvate Kinase**: This enzyme catalyzes the conversion of phosphoenolpyruvate to pyruvate. It is not involved in the conversion of fructose-6-phosphate, so this option is also incorrect.

4. **Conclusion**:
- The correct answer is **phosphofructokinase (PFK)**, as it is the enzyme required for the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate.

### Final Answer:
The conversion of fructose-6-phosphate to fructose-1,6-bisphosphate in respiration requires **phosphofructokinase (PFK)**.