LIFE SCIENCE

Detailed explanation-1: -There are three amino acids that have basic side chains at neutral pH. These are arginine (Arg), lysine (Lys), and histidine (His). Their side chains contain nitrogen and resemble ammonia, which is a base. Their pKa’s are high enough that they tend to bind protons, gaining a positive charge in the process.

Detailed explanation-2: -At the “center” of each amino acid is a carbon called the carbon and attached to it are four groups-a hydrogen, an -carboxyl group, an -amine group, and an R-group, sometimes referred to as a side chain.

Detailed explanation-3: -Arginine has guanidine moiety in its side chain hence it is the most basic amino acid.