Microbes that cannnot be cultured in cell - free extracts are

Options

A. Bacteria
B. fungi
C. Viruses
D. Algae

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about microbes that cannot be cultured in cell-free extracts. We need to identify which of the given options (bacteria, fungi, viruses, or algae) fits this description.

2. **Defining Cell-Free Extracts**: A cell-free extract is a fluid obtained by breaking open cells. This fluid contains most of the soluble molecules found in the cell, which are necessary for various biochemical processes.

3. **Analyzing the Options**:
- **Bacteria**: Bacteria have a cellular structure and can be cultured in cell-free extracts. Therefore, they are not the answer.
- **Fungi**: Fungi also possess a cellular structure and can be cultured in cell-free extracts. Hence, they are not the answer.
- **Algae**: Algae are similar to bacteria and fungi in that they have a cellular structure and can be cultured in cell-free extracts. Thus, they are not the answer.
- **Viruses**: Viruses are unique because they do not have a cellular structure. They consist of genetic material (RNA or DNA) and a protein coat but lack the cellular machinery necessary for independent replication. They can only replicate inside a host cell.

4. **Conclusion**: Since viruses do not have a cellular structure and cannot be cultured in cell-free extracts, the correct answer to the question is **viruses**.

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