How many spirals (twins or helices) a DNA of 2000 base pairs will have?

Options

A. 2000
B. 4000
C. 200
D. 45.5

Answer

To determine how many spirals (or helices) a DNA molecule with 2000 base pairs will have, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of DNA**: DNA is structured as a double helix, and it is composed of base pairs. Each complete turn (or spiral) of the helix contains a specific number of base pairs.

2. **Identify the Number of Base Pairs per Helix Turn**: It is known that one complete turn of the DNA helix contains approximately 10 base pairs.

3. **Calculate the Total Number of Helices**: To find out how many helices are present in a DNA strand with 2000 base pairs, we can use the formula:
\[ \text{Number of helices} = \frac{\text{Total base pairs}}{\text{Base pairs per helix turn}} \]
Plugging in the values:
\[ \text{Number of helices} = \frac{2000 \text{ base pairs}}{10 \text{ base pairs/helix}} = 200 \]

4. **Conclusion**: Therefore, a DNA molecule with 2000 base pairs will have 200 helices.

### Final Answer:
The number of helices for 2000 base pairs of DNA is **200**.

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