Transport of ammonia from skeletal muscle to the liver takes... | Agrigyan

Standard IUPAC amino acid nomenclature: Alanine = Ala (A), Tryptophan = Trp (W), Phenylalanine = Phe (F). The other options contain errors: Tyrosine is Y (T is Threonine); Lysine is K (L is Leucine) and Arginine is R; Asparagine is N (D is Aspartate) and Glutamate is E (G is Glycine).

Assertion (A) is false because proteins exhibit maximum UV light absorption at 280 nm (nucleic acids absorb maximally at 260 nm). Reason (R) is true because aromatic amino acid residues—primarily tryptophan and tyrosine—possess conjugated aromatic ring systems with absorption peaks near 280 nm.

While the average molecular weight of free standard amino acids is approximately 128 Da (weighted for abundance in globular proteins), the elimination of a water molecule ($18\text{ Da}$) during peptide bond condensation reduces the average molecular weight of an amino acid residue to approximately 110 daltons.