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Experiment No: 01
Aim: To determine the absorption maxima (λ_max) of nucleic acids (DNA/RNA) and
proteins using a UV-visible spectrophotometer.
Principle:
UV-visible spectrophotometry measures the absorbance of light by a sample at different
wavelengths to determine its absorption characteristics. Both nucleic acids and proteins
absorb UV light at specific wavelengths due to their inherent chemical structures.
1. Nucleic Acids:
DNA: Absorbs maximally at 260 nm due to the presence of aromatic bases
like adenine, guanine, cytosine, and thymine
RNA: Also absorbs at 260 nm ,but may have a slight additional peak
around 280 nm due to the presence of ribose sugar and different base
composition compared to DNA.
2. Proteins:
Proteins absorb UV light primarily at 280 nm due to the presence of
aromatic amino acids such as tryptophan and tyrosine.
The absorption maxima (λ_max) for these biomolecules are indicative of their concentration
and purity, as well as the presence of contaminants.
1
Experiment No: 01
Aim: To determine the absorption maxima (λ_max) of nucleic acids (DNA/RNA) and
proteins using a UV-visible spectrophotometer.
Principle:
UV-visible spectrophotometry measures the absorbance of light by a sample at different
wavelengths to determine its absorption characteristics. Both nucleic acids and proteins
absorb UV light at specific wavelengths due to their inherent chemical structures.
1. Nucleic Acids:
DNA: Absorbs maximally at 260 nm due to the presence of aromatic bases
like adenine, guanine, cytosine, and thymine
RNA: Also absorbs at 260 nm ,but may have a slight additional peak
around 280 nm due to the presence of ribose sugar and different base
composition compared to DNA.
2. Proteins:
Proteins absorb UV light primarily at 280 nm due to the presence of
aromatic amino acids such as tryptophan and tyrosine.
The absorption maxima (λ_max) for these biomolecules are indicative of their concentration
and purity, as well as the presence of contaminants.
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