In glycolysis, ATP is used in which of the following reactions?

Options

A. Conversion of fructose 6- phosphate to fructose 1, 6 - bisphosphate
B. Conversion of 3- phosphoglyceraldehyde is converted to 1, 3- bisphosphoglycerate
C. Conversion of glucose into glucose 6-phosphate
D. Both (A) and (C )

Answer

To answer the question regarding the use of ATP in glycolysis, we can break down the process step by step:

### Step 1: Understanding Glycolysis
Glycolysis is a metabolic pathway that breaks down glucose into pyruvate. This process occurs in the cytoplasm of the cell and consists of a series of ten enzymatic reactions.

### Step 2: Identifying Key Reactions
In glycolysis, there are specific steps where ATP is utilized. The two key reactions where ATP is consumed are:

1. **Conversion of Glucose to Glucose-6-Phosphate**:
- **Enzyme**: Hexokinase
- **Reaction**: Glucose + ATP → Glucose-6-Phosphate + ADP
- **ATP Used**: 1 ATP is consumed in this reaction.

2. **Conversion of Fructose-6-Phosphate to Fructose-1,6-Bisphosphate**:
- **Enzyme**: Phosphofructokinase
- **Reaction**: Fructose-6-Phosphate + ATP → Fructose-1,6-Bisphosphate + ADP
- **ATP Used**: 1 ATP is consumed in this reaction.

### Step 3: Summary of ATP Usage
In total, glycolysis uses **2 ATP molecules**:
- 1 ATP is used in the conversion of glucose to glucose-6-phosphate.
- 1 ATP is used in the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate.

### Conclusion
Thus, ATP is used in the first and third steps of glycolysis, specifically in the reactions catalyzed by hexokinase and phosphofructokinase.

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