The property of protein to absorb UV rays of light is due to:
**Core Concept**
The property of proteins to absorb ultraviolet (UV) rays of light is a fundamental concept in biochemistry, where proteins exhibit unique optical properties due to the presence of aromatic amino acids.
**Why the Correct Answer is Right**
This phenomenon is primarily attributed to the presence of tyrosine and tryptophan residues within the protein structure. These aromatic amino acids contain a benzene ring, which is capable of absorbing UV radiation. The absorption of UV light is a result of the electronic transitions that occur within the aromatic rings of these amino acids. This property is often exploited in techniques such as ultraviolet-visible spectroscopy to determine the concentration and purity of proteins.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it does not specifically relate to the optical properties of proteins. While nucleic acids do contain aromatic bases, their absorption spectra are distinct from those of proteins.
**Option B:** Incorrect because it refers to a different type of optical property, which is not relevant to the question.
**Option C:** Incorrect because it is a type of spectroscopy, but does not specifically relate to the absorption of UV light by proteins.
**Clinical Pearl / High-Yield Fact**
Remember that the absorption of UV light by proteins is a key feature of many biochemical assays, including ultraviolet-visible spectroscopy, which is commonly used to determine protein concentration and purity.
**Correct Answer:** C.