3.1 Amino Acids and Their Polymerization

amino acids

a small organic molecule with a central carbon atom bonded to an amino group (-NH₃), a carboxyl group (-COOH), a hydrogen atom, and a side chain. When amino acids are linked together to form proteins, they are referred to as residues.

4 components to an amino acid

1. Hydrogen atom

2. amino functional group

3. carboxyl functional group

4. distinctive R-group (aka side chain)

R group/ side chain

part of an amino acid’s core structure that varies from a single hydrogen atom to large structures containing carbon rings. R-group variability is responsible for the variability in amino acid structure and function

Amino acid R-groups can be divided into three general types

1. charged (acidic/basic)

2. uncharged polar

3. nonpolar

peptide bond

a covalent bond formed by a condensation reaction between two amino acids (C-N covalent bond)

oligopeptide

generally when fewer than 50 amino acids are linked together

polypeptides

polymers that contain 50 or more amino acids

protein

a macromolecule consisting of one or more polypeptide chains. each polypeptide has a unique sequence of amino acids and each protein generally possesses a characteristic 3-dimensional shape