The correcrt sequence of electron acceptor in ATP synthesis is

Options

A. Cyt. `a, c, a_(3), a`
B. Cyt. `c,b,a,a_(3)`
C. Cyt. `a_(3),a,b,c`
D. Cyt. `b,c,a,a_(3)`

Answer

To determine the correct sequence of electron acceptors in ATP synthesis, we need to understand the process of oxidative phosphorylation and the role of various cytochromes in the electron transport chain (ETC).

### Step-by-Step Solution:

1. **Understanding ATP Synthesis**: ATP synthesis primarily occurs in the mitochondria through a process called oxidative phosphorylation, which involves the electron transport chain (ETC).

2. **Role of Electron Transport Chain**: The ETC consists of a series of protein complexes and cytochromes that facilitate the transfer of electrons derived from NADH and FADH2 (produced during glycolysis and the Krebs cycle) to molecular oxygen.

3. **Identifying Cytochromes**: The main cytochromes involved in the electron transport chain are:
- Cytochrome b
- Cytochrome c1
- Cytochrome c
- Cytochrome a
- Cytochrome a3

4. **Sequence of Electron Acceptors**: The correct sequence of electron transfer in the ETC is as follows:
- Electrons are first transferred to **Cytochrome b**.
- From Cytochrome b, they move to **Cytochrome c1**.
- Then, they are transferred to **Cytochrome c**.
- Finally, the electrons are accepted by **Cytochrome a** and then **Cytochrome a3**, which ultimately transfers them to molecular oxygen (O2).

5. **Conclusion**: Therefore, the correct sequence of electron acceptors in ATP synthesis is:
- **Cytochrome b → Cytochrome c1 → Cytochrome c → Cytochrome a → Cytochrome a3**.

6. **Final Answer**: Based on the above sequence, the correct answer is option D: **Cytochrome B, Cytochrome C1, Cytochrome C, Cytochrome A, Cytochrome A3**.