The electron transport chain of photosynthesis is initiated by the absorbance of light by the

Options

A. Photosystem II `(P_(680))`
B. Photosystem I `(P_(680))`
C. Photosystem I `(P_(700))`
D. Photosystem II (P700)

Answer

**Step-by-Step Solution:**

1. **Understanding the Photosystems**: Photosynthesis involves two main photosystems: Photosystem I (PS I) and Photosystem II (PS II). Each photosystem has a specific reaction center characterized by its peak absorption wavelength.

2. **Identifying the Reaction Centers**:
- Photosystem I has a reaction center known as P700, which absorbs light most efficiently at a wavelength of 700 nm.
- Photosystem II has a reaction center known as P680, which absorbs light most efficiently at a wavelength of 680 nm.

3. **Initiation of the Electron Transport Chain**: The electron transport chain in photosynthesis is initiated when light is absorbed by the reaction center of Photosystem II (P680). This process is part of non-cyclic photophosphorylation.

4. **Process of Electron Transport**:
- When light is absorbed by P680 in Photosystem II, it excites electrons, which are then transferred to a series of proteins in the electron transport chain.
- The electrons lost from Photosystem II are replaced by electrons derived from the splitting of water molecules (photolysis).

5. **Conclusion**: Therefore, the electron transport chain of photosynthesis is initiated by the absorption of light by Photosystem II (P680).

**Final Answer**: The electron transport chain of photosynthesis is initiated by the absorption of light by Photosystem II (P680).

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