During light reaction of photosynthesis, which of the following phenomena is observed during cyclic and non-cyclic photophosphorylation ?

Options

A. Formation of ATP
B. Formation of `NADH_(2)`
C. Release of `O_(2)`
D. Involvement of PS I and PS II both

Answer

To answer the question regarding the phenomena observed during cyclic and non-cyclic photophosphorylation during the light reaction of photosynthesis, we can break down the concepts step by step.

### Step-by-Step Solution:

1. **Understanding Photophosphorylation**:
- Photophosphorylation is the process of converting ADP to ATP using the energy from light during photosynthesis. There are two types: cyclic and non-cyclic photophosphorylation.

2. **Cyclic Photophosphorylation**:
- In cyclic photophosphorylation, only **Photosystem I (PSI)** is involved.
- The electrons are excited by light energy and are transferred through a series of proteins in the electron transport chain, ultimately returning to PSI.
- This process generates **ATP** but does not produce **NADPH** or release **oxygen**.

3. **Non-Cyclic Photophosphorylation**:
- In non-cyclic photophosphorylation, both **Photosystem I (PSI)** and **Photosystem II (PSII)** are involved.
- Light energy excites electrons in PSII, which are then transferred through the electron transport chain. Water is split (photolysis), releasing oxygen as a by-product.
- This process generates **ATP** and also produces **NADPH**.

4. **Comparison of Both Processes**:
- **ATP Production**: Both cyclic and non-cyclic photophosphorylation produce ATP.
- **NADPH Production**: NADPH is produced only in non-cyclic photophosphorylation.
- **Oxygen Release**: Oxygen is released only during non-cyclic photophosphorylation due to the photolysis of water.
- **Involvement of Photosystems**: Cyclic photophosphorylation involves only PSI, while non-cyclic involves both PSI and PSII.

5. **Conclusion**:
- The phenomena observed during both cyclic and non-cyclic photophosphorylation include the production of ATP. However, NADPH and oxygen are produced only in non-cyclic photophosphorylation.

### Final Answer:
The correct answer to the question is that **ATP is produced during both cyclic and non-cyclic photophosphorylation**.