Final answer:
When glycine and alanine bond, only one dipeptide is formed because each amino acid can bond in only one specific way due to the presence of a single amino group and a single carboxyl group in their structures. Option a
Step-by-step explanation:
When a molecule of glycine bonds to a molecule of alanine, only one compound can be made, which is a dipeptide. This is because each amino acid has only one amino group and one carboxyl group that are capable of forming a peptide bond.
When they join, they form a dipeptide with a specific sequence (glycine-alanine or alanine-glycine), depending on which amino acid is at the N-terminus and which is at the C-terminus.
Despite glycine being achiral, the resulting dipeptide with alanine will only have one structure. Therefore, the correct answer to how many different compounds can be made is: a. one.