Photosynthetic bacteria include

Options

A. Nitrobacter and Nitrosomonas
B. Chlorobium and Rhodospirillum
C. Streptococcus
D. Chlorobium and Clostridium.

Answer

To answer the question "Photosynthetic bacteria include," we will analyze the provided options step by step.

### Step 1: Understand the Classification of Bacteria
Bacteria can be classified based on their mode of nutrition into two main categories:
1. **Heterotrophic Bacteria**: These bacteria obtain their food from other organisms. They can be further classified into:
- Parasitic (harm the host)
- Symbiotic (live in a mutually beneficial relationship)
- Saprophytic (feed on dead and decaying matter)

2. **Autotrophic Bacteria**: These bacteria can produce their own food. They are divided into:
- **Photosynthetic Bacteria**: Use light energy to convert carbon dioxide and water into glucose and oxygen.
- **Chemosynthetic Bacteria**: Obtain energy from chemical reactions, often involving inorganic substances.

### Step 2: Analyze Each Option
Now, let's evaluate each option given in the question:

1. **Nitrobacter and Nitrosomonas**:
- Both are known to be **chemosynthetic** bacteria, which means they do not perform photosynthesis.
- **Conclusion**: This option is incorrect.

2. **Chlorobium and Rhodospirillum**:
- Both of these bacteria are known to be **photosynthetic**. Chlorobium is a green sulfur bacterium, and Rhodospirillum is a purple non-sulfur bacterium, both capable of photosynthesis.
- **Conclusion**: This option is correct.

3. **Streptococcus**:
- Streptococcus is a genus of bacteria that is primarily **parasitic**. It is known for causing infections such as pneumonia.
- **Conclusion**: This option is incorrect.

4. **Chlorobium and Clostridium**:
- Chlorobium is photosynthetic, but Clostridium is primarily **parasitic** and does not perform photosynthesis.
- **Conclusion**: This option is incorrect.

### Final Answer
Based on the analysis, the correct answer to the question "Photosynthetic bacteria include" is:
**Chlorobium and Rhodospirillum**.

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