Describe how the r group in each of the 20 differebt amino acids determines each amino acid's characteristics

The polarity and acid/base character of each R group is the main factor determining the characteristics of an amino acid.

There are four types of R groups:

• nonpolar, e. g., CH₃ in alanine

• polar, e. g., CH₂OH in serine

• acidic. e. g., CH₂COOH in aspartic acid

• basic, e. g., CH₂ (CH₂) ₃NH₂ in lysine

The R group determines whether an amino acid is acidic, basic, or neutral.

However, the nature of the R groups is the major factor that determines the 2° and 3° structures of polypeptides and proteins.