The sequential order in electron transport from PS `II` to PS `I` of photosynthesis is

Options

A. `FeS, PQ, PC` and Cytochrome
B. `FeQ, PQ`, Cytochromes and `PC`
C. `PQ`, Cytochromes, `PC` and `FeS`
D. `PC`, Cytochromes, `FeS, PQ`

Answer

To determine the sequential order of electron transport from Photosystem II (PS II) to Photosystem I (PS I) during photosynthesis, we can break down the process step by step:

### Step-by-Step Solution:

1. **Excitation of Electrons in PS II**:
- Light energy is absorbed by chlorophyll in PS II (specifically at the P680 reaction center), which excites electrons.

2. **Primary Electron Acceptor**:
- The excited electrons are transferred to a primary electron acceptor, which is quinone (often referred to as QA or QB).

3. **Electron Transport Chain**:
- From the primary acceptor, the electrons are passed along an electron transport chain. The first component in this chain is plastoquinone (PQ).

4. **Cytochrome Complex**:
- The electrons are then transferred to the cytochrome b6f complex, which is a part of the electron transport chain.

5. **Plastocyanin**:
- After passing through the cytochrome complex, the electrons are transferred to plastocyanin (PC).

6. **Transfer to PS I**:
- The electrons from plastocyanin are then transferred to PS I (specifically at the P700 reaction center).

7. **Ferredoxin**:
- In PS I, the electrons are excited again and passed to ferredoxin (Fd).

8. **Formation of NADPH**:
- Finally, the electrons are transferred from reduced ferredoxin to NADP+ to form NADPH, catalyzed by the enzyme ferredoxin-NADP+ reductase.

### Final Order of Electron Transport:
The sequential order in electron transport from PS II to PS I is:
- PS II (P680) → Quinone (QA/QB) → Plastoquinone (PQ) → Cytochrome Complex → Plastocyanin (PC) → PS I (P700) → Ferredoxin (Fd) → NADP+ → NADPH.

### Answer:
The correct sequence is **PQ → Cytochrome Complex → Plastocyanin → PS I → Ferredoxin → NADP+**.