Which of the following groups contains amino acids with sidechains that are all strong absorbers of ultraviolet (UV) radiation?
A) Glycine and alanine
B) Alanine and tyrosine
C) Tyrosine and tryptophan
D) Phenylalanine and lysine
E) Glutamic acid and lysine

Question

Quizplus · Accepted Answer

Tyrosine and tryptophan both have aromatic sidechains that are strong absorbers of UV radiation. Glycine and alanine have no aromatic sidechains and absorb very little UV radiation. Alanine and lysine have only weakly absorbing sidechains. Phenylalanine has a strongly absorbing sidechain but lysine does not. Glutamic acid has no aromatic sidechain and absorbs very little UV radiation, while lysine has a weakly absorbing sidechain.

Which of the Following Groups Contains Amino Acids with Sidechains