Which of the following DNA form has maximum number of bases pairs per turn ?

Options

A. A-DNA
B. B-DNA
C. C-DNA
D. Z-DNA

Answer

To determine which DNA form has the maximum number of base pairs per turn, we need to analyze the different forms of DNA based on the information provided.

### Step-by-Step Solution:

1. **Identify the DNA Forms**: The four forms of DNA we need to consider are:
- A DNA
- B DNA
- C DNA
- Z DNA

2. **Understand the Characteristics of Each Form**:
- **A DNA**: This form has approximately 11 base pairs per turn.
- **B DNA**: This is the most common form of DNA, with about 10 base pairs per turn (or approximately 10.5 base pairs per turn in some measurements).
- **C DNA**: This form has about 9.33 base pairs per turn.
- **Z DNA**: This is a left-handed helix and has approximately 12 base pairs per turn.

3. **Compare the Number of Base Pairs**:
- A DNA: 11 base pairs/turn
- B DNA: 10 (or 10.5) base pairs/turn
- C DNA: 9.33 base pairs/turn
- Z DNA: 12 base pairs/turn

4. **Determine the Maximum**: From the comparison, we can see that Z DNA has the highest number of base pairs per turn, which is 12.

5. **Conclusion**: Therefore, the DNA form with the maximum number of base pairs per turn is **Z DNA**.

### Final Answer: Z DNA

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