Cytoplasmic streaming is a characteristic of plant cells, Amoeba & WBC. It is caused by

Options

A. sliding microtubules
B. contracting microfilaments
C. change in turgor pressure
D. growth of cell

Answer

**Step-by-Step Solution:**

1. **Understanding Cytoplasmic Streaming**: Cytoplasmic streaming, also known as protoplasmic streaming or cyclosis, refers to the movement of the cytoplasm within a cell. This process is essential for the distribution of nutrients, organelles, and other materials throughout the cell.

2. **Identifying the Role of the Cytoskeleton**: The cytoskeleton is a network of fibrous and tubular structures within eukaryotic cells. It provides structural support, maintains the cell's shape, and facilitates intracellular transport.

3. **Types of Cytoskeletal Structures**: The cytoskeleton is composed of three main types of structures:
- Microfilaments
- Intermediate filaments
- Microtubules

4. **Focusing on Microfilaments**: Among these structures, microfilaments, which are made of actin, play a crucial role in cytoplasmic streaming. They are ultramicroscopic and contractile in nature, meaning they can change shape and facilitate movement.

5. **Mechanism of Cytoplasmic Streaming**: The contraction of microfilaments, often in association with myosin, enables the movement of cytoplasm. This contractile machinery is responsible for various cellular movements, including the formation of pseudopodia in amoeba and white blood cells (WBCs).

6. **Eliminating Incorrect Options**:
- Sliding microtubules do not directly cause cytoplasmic streaming.
- Changes in turgor pressure are not the primary cause of cytoplasmic streaming.
- The growth of the cell is unrelated to the mechanism of cytoplasmic streaming.

7. **Conclusion**: Based on the analysis, the correct answer is that cytoplasmic streaming is caused by **contractile microfilaments**.

**Final Answer**: Cytoplasmic streaming is caused by **contractile microfilaments**.

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