Which among the following is not a prokaryote

Options

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

Answer

### Step-by-Step Solution:

1. **Understanding Prokaryotes**: Prokaryotes are organisms that lack a true nucleus and membrane-bound organelles. They are characterized by their simple cell structure. The main groups of prokaryotes include bacteria, cyanobacteria (blue-green algae), and archaebacteria.

2. **Identifying the Options**: The question provides four options:
- A) Ocellatria
- B) Nostoc
- C) Mycobacterium
- D) Saccharomyces

3. **Analyzing Each Option**:
- **Option A: Ocellatria**: This organism is a type of cyanobacteria, which falls under the category of prokaryotes.
- **Option B: Nostoc**: Similar to Ocellatria, Nostoc is also a cyanobacterium and is classified as a prokaryote.
- **Option C: Mycobacterium**: This genus includes pathogenic bacteria, such as Mycobacterium tuberculosis, and is classified as eubacteria, which are prokaryotes.
- **Option D: Saccharomyces**: This is a genus of yeast that belongs to the kingdom Fungi. Yeasts are eukaryotic organisms, meaning they have a true nucleus and membrane-bound organelles.

4. **Conclusion**: Since Saccharomyces is the only organism in the list that is not a prokaryote, the correct answer to the question is **D) Saccharomyces**.