Which step is important for continuity of glycolysis in anaerobic respiration ?

Options

A. Oxidation of PGAL
B. Substrate level phosphorylation
C. Oxidation of NADN
D. Formation pyruvic acid.

Answer

To determine which step is important for the continuity of glycolysis in anaerobic respiration, we can break down the process step by step.

### Step-by-Step Solution:

1. **Understanding Glycolysis**: Glycolysis is the metabolic pathway that converts glucose into pyruvate, producing a small amount of ATP and NADH in the process. This occurs in the cytoplasm and does not require oxygen.

2. **Anaerobic Conditions**: In the absence of oxygen (anaerobic conditions), the pyruvate produced from glycolysis cannot enter the mitochondria for further oxidation in the TCA cycle. Instead, it must undergo fermentation to regenerate NAD+.

3. **Role of NAD+**: NAD+ is a crucial coenzyme in glycolysis that accepts electrons during the oxidation of glucose. For glycolysis to continue, NAD+ must be regenerated from NADH.

4. **Regeneration of NAD+**: In anaerobic respiration, the regeneration of NAD+ occurs through the reduction of pyruvate to lactate (in animals) or ethanol and carbon dioxide (in yeast). This process is essential because it allows glycolysis to continue by ensuring a supply of NAD+.

5. **Key Step for Continuity**: The key step that ensures the continuity of glycolysis in anaerobic conditions is the oxidation of NADH back to NAD+. This is achieved during the conversion of pyruvate to lactate or ethanol, depending on the organism.

6. **Conclusion**: Therefore, the important step for the continuity of glycolysis in anaerobic respiration is the oxidation of NADH to NAD+.

### Final Answer:
The important step for the continuity of glycolysis in anaerobic respiration is the oxidation of NADH to NAD+.

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