Heavy meromyosin stands for

Options

A. The tail of meromyosin
B. The head of cross arm of meromyosin
C. The head and tail of meromyosin
D. The cross arm and tail of meromyosin

Answer

**Step-by-Step Solution:**

1. **Understanding Meromyosin**: Meromyosin is a monomeric unit of myosin, which is a contractile protein found in muscle fibers. It is important to note that myosin is a thick filament in muscle tissue.

2. **Components of Meromyosin**: Each meromyosin molecule consists of two main parts: a globular head with a short arm and a tail.

3. **Defining Heavy Meromyosin (HMM)**: Heavy meromyosin refers specifically to the portion of meromyosin that includes the globular head and the short arm. This is the part that interacts with actin filaments during muscle contraction.

4. **Defining Light Meromyosin (LMM)**: The tail portion of meromyosin is called light meromyosin. This part does not have the active sites for ATP or actin binding.

5. **Identifying the Correct Answer**: The question asks what heavy meromyosin stands for. Based on the definitions, heavy meromyosin refers to the head and short arm of meromyosin, which is responsible for binding to actin and ATP.

6. **Conclusion**: Therefore, the correct answer is that heavy meromyosin stands for the head and short arm of meromyosin.

**Final Answer**: Heavy meromyosin stands for the head and short arm of meromyosin.

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