IF DNA has 10 spirals,t he length of DNA will be

Options

A. 34Å
B. 340Å
C. 640Å
D. 64Å

Answer

To solve the question regarding the length of DNA when 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, which means it has a spiral shape. Each complete turn of the helix is referred to as a "spiral."

2. **Identify the Given Information**:
- The question states that there are 10 spirals in the DNA.

3. **Know the Helix Pitch**:
- The helix pitch of B-DNA (the most common form of DNA) is approximately 34 angstroms. This means that for every complete turn of the DNA helix, the length of the DNA is 34 angstroms.

4. **Calculate the Total Length of DNA**:
- To find the total length of the DNA, we multiply the number of spirals by the helix pitch.
- Formula:
\[ \text{Length of DNA} = \text{Number of Spirals} \times \text{Helix Pitch} \]
- Substituting the values:
\[ \text{Length of DNA} = 10 \text{ spirals} \times 34 \text{ angstroms} = 340 \text{ angstroms} \]

5. **Select the Correct Option**:
- From the calculations, the total length of DNA is 340 angstroms. Therefore, the correct answer is option 2: 340 angstroms.

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

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