During non- cyclic photophosphorylation ATP molecules are produced through electron flow

Options

A. from `H_2O` to PS II
B. from PS II to PS I.
C. from PS I to NADP
D. from PS I to ferredoxin

Answer

### 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 embedded in the thylakoid membrane.

2. **Role of Photosystems**: There are two main photosystems involved in this process: Photosystem II (PSII) and Photosystem I (PSI). PSII absorbs light energy, which excites electrons, and these electrons are transferred to an electron transport chain.

3. **Electron Flow**: The excited electrons from PSII are transferred through various electron carriers to PSI. This flow of electrons generates energy, which is used to convert ADP and inorganic phosphate (Pi) into ATP through a process called photophosphorylation.

4. **ATP Production**: As the electrons move from PSII to PSI, the energy released during this transfer is harnessed to synthesize ATP. This ATP is crucial for the subsequent light-independent reactions (Calvin cycle) of photosynthesis.

5. **Final Electron Transfer**: After reaching PSI, the electrons are again excited by light energy and eventually transferred to NADP+, forming NADPH. This process occurs in the stroma of the chloroplast.

6. **Conclusion**: Therefore, during non-cyclic photophosphorylation, ATP molecules are produced through the electron flow from Photosystem II (PSII) to Photosystem I (PSI).

### Answer:
The correct answer is that ATP molecules are produced through electron flow from **Photosystem II (PSII) to Photosystem I (PSI)**.

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