a_ donates high energy and phosohate to ADP, production of ATP. B_ is again formed in relaxing muscle is using c_ and b_ . Choose the option which correctly fills up the blanks a, b,c, d

Options

A. a = Creatin ,b=Phosphocreatine , c=ADP , d= creatine
B. a=Phosphocreatine ,b=Phosphocreatine , c= ATP ,d=creatine
C. a = Creatin ,b= Creatin ,c=ADP, d= Creatin
D. a=Phosphocreatine, b =Creatine, c=ATP d= Phonephocreatine

Answer

To solve the question, we need to fill in the blanks A, B, C, and D based on the context provided about muscle contraction and relaxation, specifically focusing on the role of phosphocreatine and ATP.

### Step-by-step Solution:

1. **Understanding the Role of A**:
- The question states that "A donates high energy and phosphate to ADP, production of ATP."
- In muscle cells, phosphocreatine (also known as creatine phosphate) donates a phosphate group to ADP to form ATP.
- Therefore, **A = Phosphocreatine**.

2. **Identifying B**:
- The next part of the question mentions "B is again formed in relaxing muscle using C and B."
- In the context of muscle relaxation, phosphocreatine (B) is regenerated from creatine (C) and ATP (D).
- Hence, **B = Phosphocreatine**.

3. **Determining C**:
- We have already established that phosphocreatine is formed from creatine and ATP during muscle relaxation.
- Therefore, **C = Creatine**.

4. **Identifying D**:
- Since ATP is used to regenerate phosphocreatine from creatine during muscle relaxation, we can conclude that **D = ATP**.

5. **Final Filling of Blanks**:
- A = Phosphocreatine
- B = Phosphocreatine
- C = Creatine
- D = ATP

### Final Answer:
- A = Phosphocreatine
- B = Phosphocreatine
- C = Creatine
- D = ATP