Red muscle fibres can be distinguished from white muscle fibres as the former have

Options

A. Less amount of mitochondria
B. Fast rate of contraction for short period
C. Less sarcoplasmic reticulum
D. Anaerobic respiration as main mode of ATP generation

Answer

To solve the question about distinguishing red muscle fibers from white muscle fibers, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Types of Muscle Fibers**:
- Red muscle fibers (also known as slow-twitch fibers) and white muscle fibers (fast-twitch fibers) are both types of skeletal muscle tissue.
- Skeletal muscles are voluntary muscles that enable movement.

2. **Identify Key Characteristics**:
- Red muscle fibers are characterized by a high content of myoglobin, which is an oxygen-binding pigment. This gives them a reddish appearance.
- White muscle fibers have lower myoglobin content, resulting in a paler color.

3. **Mitochondria Content**:
- Red muscle fibers are rich in mitochondria, which are the sites of aerobic respiration. This allows them to sustain contractions over a longer period without fatigue.
- White muscle fibers have fewer mitochondria and rely more on anaerobic respiration, which provides energy quickly but is not sustainable for long periods.

4. **Sarcoplasmic Reticulum**:
- Red muscle fibers have less developed sarcoplasmic reticulum compared to white muscle fibers, which have a well-developed sarcoplasmic reticulum that facilitates quick contractions.

5. **Contraction Rate**:
- Red muscle fibers contract slowly and can sustain contractions, while white muscle fibers contract quickly but cannot maintain this for long.

6. **Conclusion**:
- The distinguishing characteristic of red muscle fibers compared to white muscle fibers is their richness in myoglobin and mitochondria, which supports aerobic respiration and sustained contractions.

### Final Answer:
Red muscle fibers can be distinguished from white muscle fibers as the former have **more myoglobin and mitochondria**, allowing for aerobic respiration and sustained contractions.