A photosynthetic organism which does not release oxygen is

Options

A. blue green alga
B. green sulphur bacterium
C. green alga
D. algal component of lichen

Answer

To determine which photosynthetic organism does not release oxygen, we can analyze the options provided: blue-green algae, green sulfur bacteria, green algae, and the algal component of lichen.

### Step-by-Step Solution:

1. **Understanding Photosynthesis**:
- Photosynthesis is a process where organisms convert light energy into chemical energy, producing glucose and oxygen as byproducts.
- Most photosynthetic organisms, such as plants and green algae, release oxygen during this process.

2. **Identifying the Organisms**:
- **Blue-green algae (Cyanobacteria)**: These are known to perform photosynthesis and release oxygen.
- **Green algae**: Similar to plants, they also release oxygen during photosynthesis.
- **Algal component of lichen**: This is usually green algae or cyanobacteria, which also release oxygen.
- **Green sulfur bacteria**: These are unique among the options as they perform photosynthesis without releasing oxygen.

3. **Characteristics of Green Sulfur Bacteria**:
- They are gram-negative bacteria and contain pigments such as chlorophyll B, D, E, and small amounts of chlorophyll A.
- They utilize a different photosynthetic pathway that does not produce oxygen as a byproduct. Instead, they may use sulfur compounds.

4. **Conclusion**:
- Based on the analysis, the photosynthetic organism that does not release oxygen is the **green sulfur bacteria**.

### Final Answer:
The photosynthetic organism which does not release oxygen is **green sulfur bacteria**.

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