In respiration

Options

A. 2 PGAL are formed in glycolysis and none in Krebs cycle
B. 6 PGAL in glycolysis, 3 PGAL in Krebs cycle
C. 8 PGAL in glycolysis, 3 PGAL in Krebs cycle
D. PGAL formation does not occur in respiration.

Answer

**Step-by-Step Solution:**

1. **Understanding Glycolysis**: Glycolysis is the first step of cellular respiration where one molecule of glucose (a 6-carbon sugar) is broken down. This process occurs in the cytoplasm of the cell.

2. **Formation of 3-PGAL**: During glycolysis, glucose is converted into two molecules of 3-phosphoglyceraldehyde (3-PGAL), which is a 3-carbon compound. This occurs through a series of enzymatic reactions.

3. **Conversion to Pyruvate**: The 3-PGAL molecules are further processed and ultimately converted into pyruvate. This step is crucial as pyruvate is a key intermediate that enters the Krebs cycle (also known as the citric acid cycle).

4. **Krebs Cycle Overview**: The Krebs cycle occurs in the mitochondria and involves the conversion of pyruvate into carbon dioxide and energy carriers (NADH and FADH2). Importantly, no 3-PGAL or any phosphoglyceraldehyde is formed during this cycle.

5. **Conclusion**: Based on the above points, the correct answer to the question is that 2 molecules of 3-PGAL are formed in glycolysis, and none are formed during the Krebs cycle.

**Final Answer**: 2-PGAL are formed in glycolysis and none in Krebs cycle.

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