Consider the following:-
1. Cytochrome `b_(6)` -
2. Cytochrome f-
3. Plastocyanin-
4. Plastoquinone-
What is the correct sequence of these in the photo-induced electron carries between PS-II to PS-I in photosynthesis?

Options

A. 4,1,2,3
B. 3,4,1,2
C. 1,2,3,4
D. 2,3,4,1

Answer

To determine the correct sequence of the photo-induced electron carriers between Photosystem II (PS-II) and Photosystem I (PS-I) in photosynthesis, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Components**: We have four components to arrange:
- Cytochrome b6
- Cytochrome f
- Plastocyanin
- Plastoquinone

2. **Understand the Electron Transport Chain**: The electron transport chain in photosynthesis involves the transfer of electrons from water (through PS-II) to NADP+ (through PS-I). The sequence of electron carriers is crucial in this process.

3. **Follow the Z Scheme**: The Z scheme describes the path of electrons during photosynthesis. In this scheme:
- Electrons are excited in PS-II (P680) and are transferred through a series of carriers before reaching PS-I (P700).

4. **Determine the Sequence of Electron Carriers**:
- The first carrier in the sequence is **Plastoquinone** (PQ), which receives electrons from the excited chlorophyll in PS-II.
- Next, the electrons move to **Cytochrome b6**.
- From Cytochrome b6, the electrons are transferred to **Cytochrome f**.
- Finally, the electrons are passed to **Plastocyanin** before reaching PS-I.

5. **Final Sequence**: Therefore, the correct sequence of the electron carriers from PS-II to PS-I is:
- **Plastoquinone → Cytochrome b6 → Cytochrome f → Plastocyanin**.

### Conclusion:
The correct order of the electron carriers is:
1. Plastoquinone (4)
2. Cytochrome b6 (1)
3. Cytochrome f (2)
4. Plastocyanin (3)