In light reactions with the breakdown of water, electrons are generated, which are then passed to the

Options

A. Oxidised `P_(700)`
B. Reduced `P_(700)`
C. Reduced `P_(680)`
D. Oxidised `P_(680)`

Answer

**Step-by-Step Solution:**

1. **Understanding Light Reactions**: Light reactions of photosynthesis occur in the thylakoid membranes of chloroplasts and require light energy to produce ATP and NADPH.

2. **Water Splitting**: During the light reactions, water (H₂O) is split into oxygen (O₂), protons (H⁺), and electrons (e⁻) through a process called photolysis. This reaction is catalyzed by the enzyme complex known as Photosystem II (PSII).

3. **Electron Generation**: The splitting of water generates electrons. These electrons are crucial for the photosynthetic process as they replace the electrons lost by chlorophyll in Photosystem II when it absorbs light.

4. **Electron Transfer**: The excited electrons from chlorophyll (specifically from the reaction center known as P680) are transferred to an electron transport chain. This is a series of proteins embedded in the thylakoid membrane that facilitate the movement of electrons.

5. **Further Electron Transfer**: After passing through the electron transport chain, the electrons eventually reach Photosystem I (PSI), specifically the reaction center known as P700. Here, they are re-excited by light energy and used to reduce NADP⁺ to NADPH.

6. **Final Outcome**: The overall result of these processes is the generation of ATP and NADPH, which are then used in the Calvin cycle to fix carbon dioxide into organic molecules.

**Final Answer**: In light reactions, electrons generated from the breakdown of water are passed to the electron transport system and then to Photosystem I (P700).

---