試題詳解

28. Which one of the following statements relating to the common amino acids is correct?
(A) Glutamine and asparagine have acidic side chains.
(B) Valine and leucine have polar side chains containing an amide group.
(C) Only phenylalanine and tyrosine absorb in the ultraviolet region near 270 nm.
(D) There are three amino acids whose side chains carry a net positive charge at pH 5.
(E) Methionine is one of three sulfur containing amino acids.