The oxidation of one `NADH_(2)` yields

Options

A. 18 ATP
B. 6 ATP
C. 3 ATP
D. 2 ATP

Answer

To solve the question regarding the oxidation of one NADH2 and how many ATP molecules it yields, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding NADH2 Production**:
- NADH2 is produced during glycolysis and the Krebs cycle (also known as the citric acid cycle). It serves as an electron carrier.

**Hint**: Remember that NADH2 is a key player in cellular respiration, particularly in glycolysis and the Krebs cycle.

2. **Oxidation in the Electron Transport Chain (ETC)**:
- NADH2 is oxidized in the electron transport chain (ETC). In this process, it donates electrons to the first complex of the ETC.

**Hint**: The electron transport chain consists of a series of protein complexes that facilitate the transfer of electrons.

3. **Proton Pumping**:
- As electrons are transferred through the complexes in the ETC, protons (H+) are pumped from the mitochondrial matrix into the intermembrane space. This creates a proton gradient.

**Hint**: The proton gradient is crucial for ATP synthesis, as it drives ATP synthase.

4. **Calculating Proton Pumping**:
- For each NADH2 oxidized, approximately 10 protons are pumped into the intermembrane space.

**Hint**: Keep in mind the relationship between protons pumped and ATP produced.

5. **ATP Synthesis**:
- The ATP synthase enzyme uses the proton gradient to synthesize ATP. It is known that approximately 4 protons are required to synthesize one molecule of ATP.

**Hint**: Use the ratio of protons to ATP to calculate the total ATP produced.

6. **Final Calculation**:
- Since 10 protons are pumped for one NADH2, we can calculate the number of ATP produced:
- 10 protons / 4 protons per ATP = 2.5 ATP.
- However, in many contexts, this is rounded to 3 ATP for simplicity.

**Hint**: Rounding is common in biological calculations, especially when options are limited.

### Conclusion:
- The oxidation of one NADH2 yields approximately **3 ATP**.