Distance between two nucleotide pairs of DNA is

Options

A. 0.34 nm
B. 34Å
C. 3.4nm
D. 34nm

Answer

To find the distance between two nucleotide pairs of DNA, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of DNA**:
- DNA is composed of nucleotides, which are the building blocks of nucleic acids. Each nucleotide consists of a nitrogenous base, a five-carbon sugar (pentose), and a phosphate group.

2. **Refer to the Watson-Crick Model**:
- The Watson-Crick model describes the structure of DNA as a double helix. This model provides important measurements related to the DNA structure.

3. **Determine the Length of a Complete Turn of the Helix**:
- According to the model, the length of one complete turn of the DNA helix is approximately 3.4 nanometers (or 34 angstroms).

4. **Count the Number of Base Pairs in One Turn**:
- In one complete turn of the DNA helix, there are 10 base pairs.

5. **Calculate the Distance Between Two Nucleotide Pairs**:
- To find the distance between a single base pair, divide the length of one complete turn by the number of base pairs:
\[ \text{Distance between two nucleotide pairs} = \frac{\text{Length of one turn}}{\text{Number of base pairs}} = \frac{3.4 \text{ nm}}{10} = 0.34 \text{ nm} \]

6. **Convert to Angstroms (if needed)**:
- Since 1 nanometer is equal to 10 angstroms, the distance can also be expressed as:
\[ 0.34 \text{ nm} = 3.4 \text{ angstroms} \]

### Final Answer:
The distance between two nucleotide pairs of DNA is **0.34 nanometers** or **3.4 angstroms**.

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