Question

1. examine the amino acids in model 1.

a. circle an amine group in the diagram.
b. draw a triangle around a carboxylic acid (carboxyl) group.

1. how are the amino acids similar to one another?
2. how are the amino acids different from one another?

Explanation:

1a. In an amino - acid structure, the amine group is $-NH_2$. Locate and circle it in the given diagram.
1b. The carboxylic acid (carboxyl) group is $-COOH$. Draw a triangle around it.

1. All amino acids have a central carbon atom bonded to an amino group ($-NH_2$), a carboxyl group ($-COOH$), a hydrogen atom, and a variable R - group. The similarity lies in the presence of the amino and carboxyl functional groups and the basic structure around the central carbon.
2. Amino acids differ in the nature of their R - groups. The R - groups can be non - polar, polar uncharged, polar charged (acidic or basic), which gives each amino acid its unique chemical and physical properties.

Answer:

1a. Circle the $-NH_2$ group in the amino - acid structure.
1b. Draw a triangle around the $-COOH$ group in the amino - acid structure.

1. All have amino and carboxyl groups and a central carbon with a hydrogen.
2. They differ in their R - groups.