Proteins are made from amino acids. An amino acid has three parts that are joined to a central carbon atom. Identify the three parts that create an amino acid.

The three parts that are joined to the central alpha carbon (Cα) atom to create an amino acid are:

1. Amino group (–NH2): A functional group consisting of a nitrogen atom attached by single bonds to hydrogen atoms, alkyl or aryl groups. In the case of amino acids, the amino group is attached directly to the central carbon atom.

2. Carboxyl group (–COOH): A functional group composed of a carbon atom double-bonded to an oxygen atom and also bonded to a hydroxyl group. This makes the carboxyl group act as an acid because it can donate a proton (H+) due to the polar covalent bond between the oxygen and hydrogen in the hydroxyl part.

3. Side chain (R group): The R group is unique to each amino acid and determines its characteristics and function. This side chain can be a hydrogen atom (as in the simplest amino acid, glycine), a carbon chain, or a more complex ring structure, like in the amino acid tryptophan. The chemical nature of the side chains can be basic, acidic, hydrophobic, or hydrophilic, which influences how the amino acids interact with one another and with other molecules.

In addition to these three parts, there is a fourth part—the hydrogen atom—that is also attached to the central carbon, making the general formula of an amino acid NH2-CHR-COOH, where "R" represents the side chain or R group specific to each amino acid.