Amino Acid

The organic compounds that combine, via peptide bond, to form proteins.

Amino acids must contain both an amino functional group and a carboxylic acid functional group bonded to the alpha carbon. The variation in amino acid composition results from the side chain that is also bonded to the alpha carbon. The fourth bond on the alpha carbon is a hydrogen.

Cellular Respiration

A series of metabolic reactions, taking place at that the cellular level, that convert organic matter (food) into a usable form of energy.

There are two types of cellular respiration: aerobic (in the presence of oxygen) and anaerobic (without oxygen).