Which stages of aerobic respiration take place in matrix of mitochondria
(i) Oxidative decarboxylation of pyruvic acid
(ii) Glycolysis
(iii) Krebs cycle
(iv) Oxidative phosphorylation

Options

A. I and ii only
B. ii and iii only
C. iii and iv only
D. I and iii only

Answer

To answer the question regarding which stages of aerobic respiration take place in the matrix of mitochondria, we will analyze each of the stages mentioned:

1. **Glycolysis**: This process occurs in the cytoplasm of the cell, not in the mitochondria. Therefore, it does not take place in the matrix of mitochondria.

2. **Oxidative Decarboxylation of Pyruvic Acid**: This stage occurs after glycolysis when pyruvic acid is transported into the mitochondria. Here, pyruvic acid is converted into acetyl-CoA, and this process takes place in the matrix of the mitochondria.

3. **Krebs Cycle**: Also known as the citric acid cycle, this stage occurs in the matrix of the mitochondria. It involves the oxidation of acetyl-CoA to produce energy carriers.

4. **Oxidative Phosphorylation**: This stage occurs in the inner mitochondrial membrane, not in the matrix. It involves the electron transport chain and chemiosmosis.

Based on this analysis, the stages of aerobic respiration that take place in the matrix of mitochondria are:

- **Oxidative Decarboxylation of Pyruvic Acid**
- **Krebs Cycle**

Thus, the correct answer to the question is that the stages that occur in the matrix of mitochondria are (i) Oxidative decarboxylation of pyruvic acid and (iii) Krebs cycle.

### Summary:
- (i) Oxidative decarboxylation of pyruvic acid: **Yes, in the matrix**
- (ii) Glycolysis: **No, in the cytoplasm**
- (iii) Krebs cycle: **Yes, in the matrix**
- (iv) Oxidative phosphorylation: **No, in the inner membrane**

### Final Answer:
(i) and (iii) are the stages that take place in the matrix of mitochondria.

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