Correct option is B
The key to answering this question lies in understanding the absorbance profiles of different molecules at UV wavelengths.
- At 280 nm: Proteins absorb strongly due to the aromatic amino acids (phenylalanine, tyrosine, and tryptophan), which lead to a peak at this wavelength.
- At 260 nm: Nucleic acids, including RNA, absorb strongly because of the nitrogenous bases (adenine, uracil, cytosine, guanine). The absorbance at 260 nm is used to detect RNA or DNA.
Now, examining the spectra:
- At 280 nm, we observe a strong peak, indicating the presence of proteins. This is typical for a protein-RNA complex, where the protein components dominate the absorbance at 280 nm.
- At 260 nm, there is also a peak, but it is smaller than the one at 280 nm. This suggests that RNA is present, as it would absorb at 260 nm, but it is not the dominant component. The combination of a large 280 nm peak (from protein) and a smaller 260 nm peak (from RNA) indicates the presence of Protein-RNA.
Thus, Option 2: Protein-RNA is the correct choice.
Information Booster:
Protein-RNA Complexes: These complexes typically show a prominent peak at 280 nm, indicative of proteins, with a smaller but noticeable peak at 260 nm due to the RNA component. This is exactly what is observed in the provided spectra. The presence of RNA is confirmed by the absorbance at 260 nm, though it is much less intense than the 280 nm peak.
Protein and Nucleic Acid Interaction: Many proteins interact with RNA to form complexes, and these complexes are often studied by their UV absorbance profiles. The smaller peak at 260 nm compared to 280 nm suggests the RNA concentration is lower than that of the protein in this particular complex.
