In which of the following parts of mitochondria succinic dehydrogenase enzyme is located ?

Options

A. Perimitochondrial space
B. Outer membrane
C. Matrix
D. Inner membrane

Explanation

To determine the location of the succinic dehydrogenase enzyme within the mitochondria, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Role of Succinic Dehydrogenase**:
- Succinic dehydrogenase is an enzyme that plays a crucial role in the citric acid cycle (also known as the TCA cycle or Krebs cycle).

2. **Identify the Structure of Mitochondria**:
- Mitochondria are double-membrane-bound organelles consisting of an outer membrane, an inner membrane, and an intermembrane space (also referred to as the perimitochondrial space).

3. **Analyze the Components of Mitochondria**:
- The **outer membrane** contains various enzymes but is not primarily involved in the citric acid cycle.
- The **inner membrane** is where the electron transport chain occurs and contains proteins essential for ATP synthesis.
- The **matrix** is the space enclosed by the inner membrane and is rich in enzymes, mitochondrial ribosomes, and DNA, and it is where the citric acid cycle takes place.

4. **Locate Succinic Dehydrogenase**:
- While succinic dehydrogenase is involved in the TCA cycle, it is not freely dissolved in the matrix. Instead, it is embedded in the inner membrane of the mitochondria, where it participates in the electron transport chain.

5. **Conclusion**:
- Based on the above analysis, the succinic dehydrogenase enzyme is located in the **inner membrane** of the mitochondria.

### Final Answer:
- The correct answer is **D) Inner membrane**.