During non-cyclic photophosporylation, electrons arecontinously lost from the reaction centre of PS II. Which source is used to replace these electrons?

Options

A. Sunlight
B. `O_(2)`
C. `H_(2)O`
D. `CO_(2)`

Explanation

**Step-by-Step Solution:**

1. **Understanding Non-Cyclic Photophosphorylation**: Non-cyclic photophosphorylation is a process that occurs during photosynthesis, specifically in the light-dependent reactions. It involves the transfer of electrons through a series of proteins in the thylakoid membrane.

2. **Role of Photosystem II (PS II)**: In this process, Photosystem II (PS II), also known as P680 due to its peak absorption wavelength, absorbs light energy. This energy excites electrons in the chlorophyll molecules of PS II.

3. **Electron Loss**: When the electrons in PS II are excited, they are transferred to an electron transport chain. As a result, PS II continuously loses electrons.

4. **Replacement of Electrons**: To maintain the function of PS II, it is essential to replace the electrons that are lost. The source of these replacement electrons is the photolysis of water.

5. **Photolysis of Water**: Photolysis is the process where water molecules are split into protons (H+), electrons (e-), and oxygen (O2) in the presence of light. This reaction is facilitated by a complex known as the oxygen-evolving complex.

6. **Conclusion**: Therefore, the electrons lost from the reaction center of PS II during non-cyclic photophosphorylation are replaced by electrons derived from the photolysis of water.

**Final Answer**: The source used to replace the lost electrons in PS II during non-cyclic photophosphorylation is water.

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