Name the protein found in isotropic and anisotriopic bands of myofibrils

Answer

### Step-by-Step Solution:

1. **Understanding Myofibrils**: Myofibrils are the basic rod-like units of a muscle cell, and they are composed of repeating units called sarcomeres. Each sarcomere contains bands that are responsible for muscle contraction.

2. **Identifying Bands**: In myofibrils, there are two types of bands: isotropic (I bands) and anisotropic (A bands). The isotropic bands appear lighter under a microscope, while the anisotropic bands appear darker.

3. **Protein in Isotropic Bands**: The protein found in the isotropic bands (I bands) is **actin**. Actin is a thin filament that plays a crucial role in muscle contraction.

4. **Protein in Anisotropic Bands**: The protein found in the anisotropic bands (A bands) is **myosin**. Myosin is a thick filament and is responsible for the contractile properties of muscle fibers.

5. **Summary of Findings**:
- **Isotropic Bands (I Bands)**: Contain **actin** (thin filaments).
- **Anisotropic Bands (A Bands)**: Contain **myosin** (thick filaments).

### Final Answer:
The proteins found in the isotropic and anisotropic bands of myofibrils are **actin** and **myosin**, respectively.

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