In photosynthesis , light reaction includes :

Options

A. Cyclin photophosphorylation
B. Non-cyclic photophosphorylation
C. Both (a) and (b)
D. None of these

Answer

To solve the question "In photosynthesis, light reaction includes:", we will break down the concepts related to light reactions in photosynthesis step by step.

### Step-by-Step Solution:

1. **Understanding Photosynthesis**:
- Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose, using carbon dioxide and water.

2. **Identifying the Phases of Photosynthesis**:
- Photosynthesis consists of two main phases: the light-dependent reactions (light reactions) and the light-independent reactions (Calvin cycle).

3. **Focusing on Light Reactions**:
- The light reactions occur in the thylakoid membranes of chloroplasts and are responsible for converting solar energy into chemical energy.

4. **Key Processes in Light Reactions**:
- The light reactions include two major processes:
- **Non-cyclic Photophosphorylation**: This process involves both Photosystem I (PSI) and Photosystem II (PSII). It results in the production of ATP and NADPH, and involves the splitting of water (photolysis), releasing oxygen as a byproduct.
- **Cyclic Photophosphorylation**: This process only involves Photosystem I (PSI) and primarily produces ATP without the production of NADPH or oxygen.

5. **Conclusion**:
- Since both cyclic and non-cyclic photophosphorylation are integral parts of the light reactions in photosynthesis, the correct answer to the question is that the light reaction includes both cyclic photophosphorylation and non-cyclic photophosphorylation.

### Final Answer:
- The light reaction in photosynthesis includes both cyclic photophosphorylation and non-cyclic photophosphorylation (Option: Both A and B).