Question

Where does variation exist in the general structure of the amino acid?

a) Amino group
b) Carboxyl group
c) R-group (side chain)
d) Central carbon

Answer 1

c) R-group (side chain). Variation in amino acids occurs in the R-group (side chain), which is attached to the central alpha carbon and gives each amino acid its unique properties.

Step-by-step explanation:

Variation in the general structure of the amino acid exists in the R-group (side chain). While amino acids all have an amino group, a carboxyl group, and are attached to a central carbon (the alpha carbon), it is the R-group that differs among amino acids.

This R-group varies from one amino acid to another and gives each amino acid its unique properties. For instance, the side chain in glycine is simply a hydrogen atom (H), while in glutamic acid, the side chain is CH₂CH₂COOH. The unique chemical properties of the variable side chains contribute to the shape of the protein, which in turn determines the function of the protein.