Amino acids can be acidic, basic or neutral depending on the relative number of their amine and carboxylic groups. You need to know which amino acids are acidic and which are basic, as it is easy to get confused between the two. The fact that amino acids behave like zwitter ions add to the confusion. So, get your concepts right!
Nature of aqueous solutions of two different amino acids X and Y are acidic and basic, respectively. X and Y can be: