Electrons from NADH produced in the mitochondrial matrix during citric acid cycle are oxidised by :-

Options

A. Complex II
B. Complex III
C. Complex I
D. Complex IV

Answer

**Step-by-Step Solution:**

1. **Understanding NADH Production**: During the citric acid cycle (Krebs cycle), NADH is produced in the mitochondrial matrix. This molecule carries high-energy electrons that are essential for cellular respiration.

2. **Oxidation of NADH**: The process of oxidation involves the conversion of NADH back to NAD+. During this process, NADH donates electrons and protons. The reaction can be represented as:
\[ \text{NADH} \rightarrow \text{NAD}^+ + \text{e}^- + \text{H}^+ \]

3. **Role of Enzymes**: The oxidation of NADH requires an enzyme. However, this enzyme is not located in the mitochondrial matrix where NADH is produced. Instead, it is found in the inner mitochondrial membrane.

4. **Electron Transport Chain (ETC)**: The electrons from NADH are transferred to the electron transport chain, which is located in the inner mitochondrial membrane (specifically in the cristae). The electron transport chain consists of several protein complexes.

5. **Identifying the Complex**: The first complex in the electron transport chain that receives electrons from NADH is known as Complex I (NADH dehydrogenase). This complex is responsible for the oxidation of NADH.

6. **Conclusion**: Therefore, the electrons from NADH produced in the mitochondrial matrix during the citric acid cycle are oxidized by Complex I of the electron transport chain.

**Final Answer**: Electrons from NADH produced in the mitochondrial matrix during the citric acid cycle are oxidized by Complex I of the electron transport chain.

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