NADH is oxidised to `NAD^(+)` in

Options

A. Aerobic respiration
B. EMP pathway
C. Fermentation
D. More than one option is correct

Answer

To answer the question "NADH is oxidized to NAD+ in", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding NADH and NAD+**:
- NADH (Nicotinamide adenine dinucleotide in its reduced form) is a coenzyme that carries electrons during cellular respiration. When NADH is oxidized, it loses electrons and is converted back to its oxidized form, NAD+.

2. **Identifying the Processes**:
- The question asks about the processes in which NADH is oxidized to NAD+. The primary processes to consider are aerobic respiration and fermentation.

3. **Aerobic Respiration**:
- In aerobic respiration, NADH is produced during glycolysis (EMP pathway) and the TCA cycle (Krebs cycle). However, NADH is oxidized back to NAD+ primarily during the electron transport chain (ETC), where NADH donates electrons.

4. **Electron Transport Chain (ETC)**:
- The electron transport chain is a series of protein complexes located in the inner mitochondrial membrane. NADH is oxidized by NADH dehydrogenase, which facilitates the transfer of electrons and leads to the production of ATP.

5. **Fermentation**:
- Fermentation is an anaerobic process that also regenerates NAD+ from NADH. In processes like lactic acid fermentation and alcoholic fermentation, NADH is oxidized back to NAD+ to allow glycolysis to continue in the absence of oxygen.

6. **Conclusion**:
- Both aerobic respiration (specifically during the electron transport chain) and fermentation lead to the oxidation of NADH to NAD+. Therefore, the correct answer includes both processes.

### Final Answer:
NADH is oxidized to NAD+ in both aerobic respiration (during the electron transport chain) and fermentation.