Membrane-bound organelles are absent in :

Options

A. Saccharomyces
B. Streptococcus
C. Chlamydomonas
D. Plasmodium

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which of the given options lacks membrane-bound organelles. Membrane-bound organelles are structures within a cell that are enclosed by membranes, such as the nucleus, mitochondria, and endoplasmic reticulum.

2. **Identifying Cell Types**: There are two main types of cells: prokaryotic and eukaryotic. Prokaryotic cells (like bacteria) do not have membrane-bound organelles, while eukaryotic cells (like fungi, plants, and animals) do.

3. **Analyzing the Options**:
- **Prokaryotes**: These are unicellular organisms and lack membrane-bound organelles. Examples include bacteria.
- **Eukaryotes**: These include organisms like fungi (e.g., Saccharomyces), green algae (e.g., Chlamydomonas), and Plasmodium. All these organisms have membrane-bound organelles.

4. **Evaluating Each Option**:
- **Saccharomyces**: This is a fungus and is eukaryotic, so it has membrane-bound organelles.
- **Streptococcus**: This is a type of bacteria and is prokaryotic, meaning it lacks membrane-bound organelles.
- **Chlamydomonas**: This is a green algae and is eukaryotic, so it has membrane-bound organelles.
- **Plasmodium**: This is a parasite and is also eukaryotic, thus it has membrane-bound organelles.

5. **Conclusion**: The only option that lacks membrane-bound organelles is **Streptococcus**, which is a prokaryote.

**Final Answer**: The correct answer is **Streptococcus**.

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