In certain biochemical reactions two redox-equivalents are removed in the form of two hydrogen atoms from PGAL and transferred to a molecule of `NAD^(+)` and NADH + `H^(+)` is formed. This NADH + `H^(+)` is finally reoxidised in :-

Options

A. Stroma of chloroplast
B. `F_(0)-F_(1)`
C. Mitochondrial matrix
D. Inner mitochondrial membrane

Answer

To answer the question about where NADH + H⁺ is finally reoxidized, we can break down the process step by step:

### Step-by-Step Solution:

1. **Understanding the Reaction**: In certain biochemical reactions, specifically during glycolysis, two hydrogen atoms are removed from PGAL (Phosphoglyceraldehyde) and transferred to NAD⁺. This process reduces NAD⁺ to NADH + H⁺.

2. **Formation of NADH + H⁺**: The reduction of NAD⁺ to NADH + H⁺ is a crucial step in cellular respiration, as NADH serves as an electron carrier.

3. **Reoxidation of NADH + H⁺**: The NADH + H⁺ produced in glycolysis needs to be reoxidized to regenerate NAD⁺ for the continuation of glycolysis and other metabolic processes.

4. **Location of Reoxidation**: The reoxidation of NADH + H⁺ occurs in the electron transport chain (ETC), which is located in the inner mitochondrial membrane. Here, NADH donates its electrons to the chain, allowing it to be oxidized back to NAD⁺.

5. **Role of the Electron Transport Chain**: In the ETC, the electrons from NADH are passed through a series of proteins, ultimately leading to the reduction of oxygen and the production of water. This process also helps in generating a proton gradient that is used to produce ATP.

6. **Conclusion**: Therefore, the final reoxidation of NADH + H⁺ occurs in the electron transport chain in the inner mitochondrial membrane.

### Final Answer:
NADH + H⁺ is finally reoxidized in the electron transport chain (ETC) located in the inner mitochondrial membrane.