Which among the following is not a prokaryot?

Options

A. Saccharomyces
B. Mycobacterium
C. Nostoc
D. Oscillatoria

Answer

To determine which organism among the given options is not a prokaryote, we need to understand the characteristics of prokaryotic and eukaryotic cells.

### Step-by-Step Solution:

1. **Define Prokaryotes**: Prokaryotes are organisms that have a primitive nucleus, meaning their genetic material (DNA) is not enclosed within a membrane. They lack membrane-bound organelles and typically have a simpler cell structure.

2. **Identify Characteristics of Prokaryotes**:
- No true nucleus (naked genetic material).
- Organelles are not membrane-bound (e.g., ribosomes are 70S).
- Examples include bacteria and archaea.

3. **Identify the Organisms Provided**:
- **Saccharomyces**: This is a genus of fungi.
- **Mycobacterium**: This is a genus of bacteria.
- **Nostoc**: This is a genus of bacteria.
- **Oxylateria**: This is also a genus of bacteria.

4. **Classify Each Organism**:
- **Saccharomyces**: Eukaryotic organism (true nucleus).
- **Mycobacterium**: Prokaryotic organism (bacteria).
- **Nostoc**: Prokaryotic organism (bacteria).
- **Oxylateria**: Prokaryotic organism (bacteria).

5. **Conclusion**: Since Saccharomyces is a eukaryotic organism and the others are prokaryotic, the answer to the question "Which among the following is not a prokaryote?" is **Saccharomyces**.

### Final Answer:
**Saccharomyces** is not a prokaryote.