Light reaction produces assimilatory power in the form of

Options

A. (a) ATP,`NADH_(2)`
B. (b) ATP, `NADPH_(2)`
C. (c) NADH
D. (d) NADP

Answer

To answer the question "Light reaction produces assimilatory power in the form of," we need to understand the processes involved in photosynthesis, particularly the light-dependent reactions.

### Step-by-Step Solution:

1. **Understanding Photosynthesis**: Photosynthesis consists of two main stages: the light-dependent reactions and the light-independent reactions (also known as the Calvin cycle or dark reactions). The light-dependent reactions occur in the presence of sunlight.

2. **Light-Dependent Reactions**: These reactions take place in the thylakoid membranes of chloroplasts. They capture light energy and convert it into chemical energy.

3. **Products of Light Reactions**: The primary products of the light-dependent reactions are ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate). Both of these molecules serve as energy carriers and are essential for the subsequent light-independent reactions.

4. **Role of ATP and NADPH**:
- **ATP** provides the energy required for various biochemical reactions.
- **NADPH** acts as a reducing agent, supplying the necessary electrons for the synthesis of carbohydrates during the light-independent reactions.

5. **Evaluating Options**:
- Option A (ATP and NADH2) is incorrect because NADH2 is primarily involved in catabolic processes, not in the light reactions of photosynthesis.
- Option B (ATP and NADPH2) is correct as both ATP and NADPH2 are produced during the light reactions and are used in the dark reactions for carbohydrate synthesis.
- Option C (NADH) is incorrect since it is not produced in the light reactions.
- Option D (NADP) is also incorrect as NADP+ is the oxidized form, not the reduced form that is produced.

6. **Conclusion**: Therefore, the correct answer is **B: ATP and NADPH2**, as these are the forms of assimilatory power produced during the light reactions of photosynthesis.