Match list-I and list-II, select the correct answer using the codes given below the lists.
`{:("List-I (Constractile proteins)","List-II (Functions)"),(A."Mysoin",1."Stabilizes F-actin"),(B."Actin",2."Calcium binding"),(C."Troponin",3."Sliding"),(D."Tropomyosin",4."ATPase activity"):}`

Options

A. 3, 4, 1, 2
B. 4, 3, 2 ,1
C. 4, 3, 1, 2
D. 3, 4, 2, 1

Answer

To solve the matching question between List-I (Contractile proteins) and List-II (Functions), we will analyze each protein and its corresponding function step by step.

### Step-by-Step Solution:

1. **Identify Myosin (A)**:
- Myosin is a muscle protein that plays a crucial role in muscle contraction.
- It hydrolyzes ATP to provide the energy necessary for muscle movement.
- **Function**: ATPase activity (4).
- **Match**: A - 4.

2. **Identify Actin (B)**:
- Actin is another essential protein involved in muscle contraction.
- It facilitates the sliding mechanism that allows muscles to contract.
- **Function**: Sliding (3).
- **Match**: B - 3.

3. **Identify Troponin (C)**:
- Troponin is a regulatory protein that binds to calcium ions.
- It plays a key role in muscle contraction by regulating the interactions between actin and myosin.
- **Function**: Calcium binding (2).
- **Match**: C - 2.

4. **Identify Tropomyosin (D)**:
- Tropomyosin is a protein that stabilizes the actin filaments (F-actin) in muscle cells.
- It prevents the binding of myosin to actin in the absence of calcium.
- **Function**: Stabilizes F-actin (1).
- **Match**: D - 1.

### Summary of Matches:
- A - 4 (Myosin - ATPase activity)
- B - 3 (Actin - Sliding)
- C - 2 (Troponin - Calcium binding)
- D - 1 (Tropomyosin - Stabilizes F-actin)

### Final Answer:
The correct matches are:
- A - 4
- B - 3
- C - 2
- D - 1

Thus, the answer is option 2 (4, 3, 2, 1).

---