DNA molecule has uniforms dimeter due to ?

Options

A. Double standed
B. Presence of phosphate
C. Specific base pairing between purine and pyrimidine
D. Specific base pairing between purine and purine

Answer

**Step-by-Step Solution:**

1. **Understanding DNA Structure**: DNA is a double-stranded molecule that has a uniform diameter. This structure is crucial for its function in genetics.

2. **Identifying Components of DNA**: DNA is made up of nucleotides, which consist of a sugar, a phosphate group, and a nitrogenous base. The nitrogenous bases are divided into two categories: purines and pyrimidines.

3. **Base Pairing**: In DNA, specific base pairing occurs between purines and pyrimidines. The purines include adenine (A) and guanine (G), while the pyrimidines include cytosine (C) and thymine (T).

4. **Hydrogen Bonding**: Adenine pairs with thymine through two hydrogen bonds, while guanine pairs with cytosine through three hydrogen bonds. This specific pairing is known as complementary base pairing.

5. **Formation of Double Helix**: The two strands of DNA coil around each other to form a double helix structure. This coiling is maintained by the uniform distance between the paired bases, contributing to the uniform diameter of the DNA molecule.

6. **Conclusion**: The uniform diameter of the DNA molecule is primarily due to the specific base pairing between purines and pyrimidines, which ensures that the distance between the two strands remains constant.

**Final Answer**: The DNA molecule has a uniform diameter due to specific base pairing between purines and pyrimidines.

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