What type of nutrition found in purple and green sulphur bacteria

Options

A. Photoautotrophic
B. Chemoautotrophic
C. Photoheterotrophic
D. Saprotrophic

Answer

### Step-by-Step Solution:

1. **Understanding the Types of Nutrition**:
- There are different types of nutritional modes in bacteria, including photoautotrophic, chemoautotrophic, photoheterotrophic, and saprotrophic. Each of these modes describes how organisms obtain energy and carbon.

2. **Defining Photoautotrophic Nutrition**:
- Photoautotrophic organisms use light energy to convert carbon dioxide and water into glucose, releasing oxygen as a byproduct. This process is typical for many plants and some bacteria.

3. **Defining Chemoautotrophic Nutrition**:
- Chemoautotrophic bacteria obtain energy by oxidizing inorganic substances (such as hydrogen sulfide) and use this energy to convert carbon dioxide into organic compounds. They do not rely on light.

4. **Defining Photoheterotrophic Nutrition**:
- Photoheterotrophic bacteria use light for energy but require organic compounds for carbon. They do not use water as a source of electrons, and instead, they may utilize hydrogen sulfide.

5. **Defining Saprotrophic Nutrition**:
- Saprotrophic organisms feed on dead and decaying organic matter. They play a crucial role in decomposition but are not relevant to the question about purple and green sulfur bacteria.

6. **Identifying the Nutrition of Purple and Green Sulfur Bacteria**:
- Purple and green sulfur bacteria are known to use light for energy and utilize hydrogen sulfide as an electron donor. They do not release oxygen but instead produce sulfur as a byproduct.

7. **Conclusion**:
- Based on the definitions and characteristics of the nutritional modes, purple and green sulfur bacteria are classified as **photoautotrophic** because they use light energy and hydrogen sulfide to produce energy and organic compounds.

### Final Answer:
The type of nutrition found in purple and green sulfur bacteria is **photoautotrophic**.

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