When `FADH_(2)//FMNH_(2)` is oxidised through ETS

Options

A. Produces 2 ATP
B. Consumes `1//2 O_(2)`
C. Both 1 and 2
D. Uses one water molecule

Answer

To answer the question "When FADH₂/FMNH₂ is oxidized through ETS," we can break down the process step by step:

### Step-by-Step Solution:

1. **Understanding FADH₂ and FMNH₂**:
- FADH₂ (Flavin Adenine Dinucleotide) and FMNH₂ (Flavin Mononucleotide) are both electron carriers involved in cellular respiration. They are reduced forms of their respective oxidized states (FAD and FMN).

2. **Role of Electron Transport System (ETS)**:
- The Electron Transport System (ETS) is a series of protein complexes located in the inner mitochondrial membrane (in eukaryotes). It is responsible for transferring electrons from electron donors like FADH₂ and FMNH₂ to electron acceptors.

3. **Oxidation of FADH₂ and FMNH₂**:
- When FADH₂ or FMNH₂ is oxidized, they donate electrons to the ETS. This process involves the transfer of electrons through various protein complexes, ultimately leading to the reduction of oxygen to water.

4. **ATP Production**:
- As electrons move through the ETS, protons (H⁺ ions) are pumped from the mitochondrial matrix into the intermembrane space, creating a proton gradient. This gradient is used by ATP synthase to produce ATP.
- Specifically, the oxidation of one molecule of FADH₂ typically results in the production of 1.5 to 2 molecules of ATP, while FMNH₂ can yield a similar amount.

5. **Final Result**:
- Therefore, when FADH₂ or FMNH₂ is oxidized through the ETS, it results in the production of approximately 2 molecules of ATP.

### Final Answer:
When FADH₂/FMNH₂ is oxidized through the Electron Transport System (ETS), approximately 2 molecules of ATP are produced.

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