Liberation of oxygen when green cells in water are exposed to sunlight in presence of suitable acceptor is

Options

A. Emerson effect
B. Blackman's reaction
C. Hill's reaction
D. Arnon reaction.

Answer

To solve the question regarding the liberation of oxygen when green cells in water are exposed to sunlight in the presence of a suitable electron acceptor, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Context**: The question refers to a specific process that occurs during photosynthesis, particularly focusing on the release of oxygen when green cells (like chloroplasts) are exposed to sunlight.

2. **Identifying Key Terms**: The terms mentioned in the question include "liberation of oxygen," "green cells," "sunlight," and "suitable acceptor." These terms are crucial for identifying the correct answer.

3. **Recalling Relevant Concepts**: In photosynthesis, particularly during the light-dependent reactions, chlorophyll absorbs sunlight and uses that energy to split water molecules (H2O). This process releases oxygen (O2) as a byproduct.

4. **Recognizing Hill's Reaction**: The specific phenomenon where oxygen is released in the presence of a suitable electron acceptor (like NADP+) is known as Hill's Reaction. This was first demonstrated by Robin Hill in 1939.

5. **Eliminating Other Options**:
- **Emerson Effect**: This refers to the phenomenon where two wavelengths of light are more effective for photosynthesis than one, but it does not specifically relate to oxygen liberation.
- **Blackman's Effect**: This refers to the concept of limiting factors in photosynthesis, not directly related to oxygen release.
- **None Reaction**: This option can be dismissed as there is a known reaction related to the question.

6. **Conclusion**: Based on the above understanding, the correct answer to the question is **Hill's Reaction**.

### Final Answer:
The liberation of oxygen when green cells in water are exposed to sunlight in the presence of a suitable acceptor is known as **Hill's Reaction**.

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