Which of the following stores calcium required for muscle contraction ?

Options

A. Smooth ER
B. Microfilaments
C. GB
D. RER

Answer

**Step-by-Step Solution:**

1. **Understanding the Role of Calcium in Muscle Contraction:**
- Calcium ions play a crucial role in muscle contraction. They are necessary for the interaction between muscle proteins, specifically actin and myosin, which are responsible for muscle contraction.

2. **Identifying the Storage Site for Calcium:**
- The question asks which structure stores calcium required for muscle contraction. Among the options provided (smooth endoplasmic reticulum, microfilaments, Golgi body, rough endoplasmic reticulum), we need to identify the correct one.

3. **Analyzing the Options:**
- **Smooth Endoplasmic Reticulum (SER):** This organelle is known for storing calcium ions in muscle cells. It is often referred to as the sarcoplasmic reticulum in muscle tissue.
- **Microfilaments:** These are primarily composed of actin and are involved in muscle contraction but do not store calcium.
- **Golgi Body:** This organelle is involved in packaging proteins and does not store calcium.
- **Rough Endoplasmic Reticulum (RER):** This is involved in protein synthesis and does not store calcium.

4. **Conclusion:**
- The smooth endoplasmic reticulum (sarcoplasmic reticulum in muscle cells) is the correct answer as it stores calcium ions necessary for muscle contraction.

**Final Answer:**
- The smooth endoplasmic reticulum (sarcoplasmic reticulum) stores calcium required for muscle contraction.

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