Which statement is wrong for Kreb's cycle?

Options

A. There are three points in the cycle where `NAD^(+)` is reduced to `NADH^(+)H^(+)`
B. There is one point in the cycle where `FAD^(+)` is reduced to `FADH_(2)`
C. During conversion of succinyl CoA succinic acid, a molecule of GTP is synthesized
D. The cycle starts with condensation of acetyl group acetyl `CoA^(0)` with pyruvic acid yield citric acid

Answer

**Step-by-Step Solution:**

1. **Understanding the Kreb's Cycle**: The Kreb's cycle, also known as the citric acid cycle or TCA cycle, is a crucial part of cellular respiration that occurs in the mitochondria. It follows glycolysis and is responsible for the oxidation of acetyl-CoA to produce energy carriers.

2. **Identifying Statements**: The question asks which statement regarding the Kreb's cycle is incorrect. We need to evaluate the provided statements one by one.

3. **Evaluating the First Statement**: The first statement claims that there are three points in the cycle where NAD+ is reduced to NADH and H+. This is true, as NAD+ is indeed reduced at three different points during the cycle.

4. **Evaluating the Second Statement**: The second statement mentions that there is a point in the cycle where FAD+ is reduced to FADH2. This is also true, as FAD+ is reduced during the conversion of succinate to fumarate.

5. **Evaluating the Third Statement**: The third statement states that during the conversion of succinyl-CoA to succinic acid, a molecule of GTP is synthesized. This is correct; GTP is produced during this conversion.

6. **Evaluating the Fourth Statement**: The fourth statement claims that the cycle starts with the condensation of acetyl group (acetyl-CoA) with pyruvic acid to yield citric acid. This statement is incorrect. The Kreb's cycle actually begins with the condensation of acetyl-CoA with oxaloacetic acid, not pyruvic acid. Pyruvic acid is converted to acetyl-CoA before entering the Kreb's cycle.

7. **Conclusion**: The wrong statement regarding the Kreb's cycle is the fourth one, as it incorrectly describes the initial reaction of the cycle.

**Final Answer**: The wrong statement for Kreb's cycle is: "The cycle starts with condensation of acetyl group (acetyl-CoA) with pyruvic acid to yield citric acid."

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