One myosin filament in the myofibril of skeletal muscle fibre is surrounded by how many actin filaments ?

Options

A. Two
B. Four
C. Six
D. Three

Answer

To determine how many actin filaments surround one myosin filament in the myofibril of skeletal muscle fiber, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Muscle Fibers**:
- Skeletal muscle fibers are composed of myofibrils, which contain repeating units called sarcomeres. Each sarcomere is the basic contractile unit of muscle.

2. **Identify the Filaments**:
- Myofibrils contain two main types of filaments: thick filaments (myosin) and thin filaments (actin). Myosin filaments are referred to as thick filaments, while actin filaments are known as thin filaments.

3. **Arrangement of Filaments**:
- In a sarcomere, each myosin filament is surrounded by actin filaments. This arrangement is crucial for muscle contraction.

4. **Count the Surrounding Actin Filaments**:
- Each myosin filament is surrounded by six actin filaments. This means that for every myosin filament, there are six actin filaments that interact with it during muscle contraction.

5. **Conclusion**:
- Therefore, the answer to the question is that one myosin filament in the myofibril of skeletal muscle fiber is surrounded by **six actin filaments**.

### Final Answer:
One myosin filament in the myofibril of skeletal muscle fiber is surrounded by **six actin filaments**.

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