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

Options

A. from `H_(2)O` to PS II
B. from PS II and PS I
C. from PSI to NADP
D. from PSI to ferredoxine

Answer

### Step-by-Step Solution:

1. **Understanding Non-Cyclic Photophosphorylation**:
Non-cyclic photophosphorylation is a process that occurs during photosynthesis where both ATP and NADPH are produced. This process involves the flow of electrons through two photosystems: Photosystem II (PSII) and Photosystem I (PSI).

2. **Location of Non-Cyclic Photophosphorylation**:
This process takes place in the thylakoid membranes of chloroplasts. It is important to note that while the question mentions mitochondria, non-cyclic photophosphorylation specifically occurs in chloroplasts.

3. **Role of Photosystems**:
- **Photosystem II (PSII)**: The process begins when light energy is absorbed by PSII, which excites electrons. These high-energy electrons are then transferred through an electron transport chain.
- **Photosystem I (PSI)**: The electrons eventually reach PSI, where they are re-excited by light energy. The flow of electrons from PSII to PSI is crucial for the production of ATP and NADPH.

4. **Production of ATP**:
As electrons move through the electron transport chain from PSII to PSI, they release energy. This energy is used to pump protons (H+) into the thylakoid lumen, creating a proton gradient. When protons flow back into the stroma through ATP synthase, ATP is produced.

5. **Production of NADPH**:
At PSI, the re-excited electrons are used to reduce NADP+ to NADPH, which is another energy carrier used in the Calvin cycle for synthesizing glucose.

6. **Comparison with Cyclic Photophosphorylation**:
In contrast, cyclic photophosphorylation involves only PSI and results in the production of ATP without the formation of NADPH. This process is used when the cell requires ATP but not NADPH.

### Final Answer:
During non-cyclic photophosphorylation, ATP molecules are produced through the flow of electrons from Photosystem II to Photosystem I, utilizing the energy released to create a proton gradient that drives ATP synthesis.