In which one of following reactions of glycolysis, oxidation takes place

Options

A. Glucose 6-P to fructose 6-P
B. Fructose 6-P to fructose 1,6-biphosphate
C. 1,3-biphosphoglycerate to 3-phosphogl- yceric acid
D. 3-phosphoglyceraldehyde to 1, 3-bipho-sphoglycerate

Answer

To determine in which reaction of glycolysis oxidation takes place, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Glycolysis**: Glycolysis is the metabolic pathway that converts glucose into pyruvate, producing ATP and NADH in the process. It occurs in the cytoplasm and consists of ten enzyme-catalyzed reactions.

2. **Identify the Reactions**: Review the reactions involved in glycolysis. The key reactions include:
- Glucose to Glucose-6-phosphate
- Glucose-6-phosphate to Fructose-6-phosphate
- Fructose-6-phosphate to Fructose-1,6-bisphosphate
- Fructose-1,6-bisphosphate to Glyceraldehyde-3-phosphate and Dihydroxyacetone phosphate
- Glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate
- 1,3-bisphosphoglycerate to 3-phosphoglycerate
- 3-phosphoglycerate to 2-phosphoglycerate
- 2-phosphoglycerate to Phosphoenolpyruvate
- Phosphoenolpyruvate to Pyruvate

3. **Identify Oxidation Reaction**: Oxidation involves the loss of electrons or hydrogen atoms. In glycolysis, the reaction where oxidation occurs is when Glyceraldehyde-3-phosphate (G3P) is converted to 1,3-bisphosphoglycerate (1,3-BPG). During this reaction, NAD+ is reduced to NADH, indicating that oxidation has taken place.

4. **Select the Correct Option**: Based on the analysis, the correct answer is the reaction:
- Glyceraldehyde-3-phosphate (G3P) → 1,3-bisphosphoglycerate (1,3-BPG)
This corresponds to option number four.

5. **Conclusion**: Therefore, the reaction in glycolysis where oxidation occurs is the conversion of Glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate.

### Final Answer:
The reaction in glycolysis where oxidation takes place is the conversion of Glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate (Option 4).

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