Ultraviolet light absorbed by nucleic acid is

Options

A. 26 nm
B. 75 nm
C. 160 nm
D. 1500 nm.

Answer

**Step-by-Step Solution:**

1. **Understanding Nucleic Acids**: Nucleic acids, such as DNA and RNA, are composed of nucleotides. Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base.

2. **Identifying Nitrogenous Bases**: The nitrogenous bases in nucleic acids are categorized into two groups: purines (adenine and guanine) and pyrimidines (cytosine and thymine in DNA; uracil replaces thymine in RNA).

3. **Structure of Nucleotides**: The nitrogenous bases are arranged in a specific structure that includes heterocyclic rings. These rings are responsible for the absorption of ultraviolet (UV) light.

4. **Absorption of Ultraviolet Light**: When nucleic acids are exposed to UV light, they absorb this light due to the presence of these heterocyclic rings. The specific wavelength at which nucleic acids absorb UV light is important for various biological processes.

5. **Peak Absorption Wavelength**: The peak absorption of UV light by nucleic acids occurs at approximately 260 nanometers (nm). At this wavelength, the energy from the UV light can break the hydrogen bonds between the nitrogenous bases.

6. **Conclusion**: Therefore, the correct answer to the question regarding the wavelength of ultraviolet light absorbed by nucleic acids is 260 nanometers.

**Final Answer**: Ultraviolet light absorbed by nucleic acid is at 260 nanometers.

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