The striated appearance of a myofibril is due to distribution pattern of

Options

A. Actin and myosin
B. Fascicles
C. Troponin
D. Meromyosin.

Answer

To solve the question regarding the striated appearance of a myofibril, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Myofibrils**: Myofibrils are the basic rod-like units of a muscle cell (muscle fiber) and are responsible for muscle contraction. They are composed of repeating units called sarcomeres.

2. **Identifying the Bands**: Myofibrils exhibit a striated appearance due to the presence of alternating dark and light bands. These bands are known as A bands (dark) and I bands (light).

3. **Components of the Bands**: The dark A bands are primarily composed of thick filaments made of myosin, while the light I bands are made of thin filaments composed of actin.

4. **Overlapping of Filaments**: The striated appearance is a result of the overlapping arrangement of these thick (myosin) and thin (actin) filaments. This overlapping creates the characteristic pattern of striations observed in skeletal muscle.

5. **Conclusion**: Therefore, the striated appearance of a myofibril is due to the distribution pattern of actin and myosin.

### Final Answer:
The striated appearance of a myofibril is due to the distribution pattern of **actin and myosin**.

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