If DNA has 10 spirals, the length of DNA will be

Options

A. `34Å`
B. `340Å`
C. `640Å`
D. `64 Å`

Answer

To determine the length of DNA given that it has 10 spirals, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of DNA**: DNA is structured as a double helix, and the distance it spirals around is referred to as the "pitch" of the helix.

2. **Identify the Pitch of DNA**: The pitch of B-DNA (the most common form of DNA) is approximately 34 Ångströms (Å). This means that for every complete turn (or spiral) of the DNA helix, it extends 34 Ångströms in length.

3. **Determine the Number of Spirals**: In this problem, we are given that the DNA has 10 spirals.

4. **Calculate the Total Length of DNA**: To find the total length of the DNA, we multiply the number of spirals by the pitch of the DNA:
\[ \text{Length of DNA} = \text{Number of Spirals} \times \text{Pitch} \]
Substituting the values we have:
\[ \text{Length of DNA} = 10 \text{ spirals} \times 34 \text{ Å} \]

5. **Perform the Calculation**:
\[ \text{Length of DNA} = 340 \text{ Å} \]

6. **Select the Correct Option**: From the options given, 340 Ångströms is one of the choices, making it the correct answer.

### Final Answer:
The length of DNA with 10 spirals is **340 Ångströms**.

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