Amino acids are organic compounds containing amine (-NH2) and carboxyl (-COOH) functional groups, along with a side chain (R group) specific to each amino acid. Amino acids are the building blocks of protein and play the important role in the body:

Break down food
Grow
Repair body tissue
Perform many other body functions

Amino acids are classified into three groups:

Essential amino acids
Nonessential amino acids
Conditional amino acids

ESSENTIAL AMINO ACIDS

Essential amino acids cannot be synthesized by the body. and thus must be supplied in its diet.

The nine amino acids humans cannot synthesize are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine,tryptophan, and valine.

NONESSENTIAL AMINO ACIDS

Nonessential means that our bodies produce an amino acid in sufficient quantities in the body even if we do not get it from the diet.

Nonessential amino acids include: alanine, asparagine, aspartic acid, and glutamic acid.

CONDITIONAL AMINO ACIDS

Conditional amino acids synthesis can be limited under special pathophysiological conditions, such as prematurity in the infant or individuals in severe catabolic distress.  You do not need to eat essential and nonessential amino acids at every meal, but getting a balance of them over the whole day is important. A diet based on a single plant item will not be adequate, but we no longer worry about pairing proteins (such as beans with rice) at a single meal. Instead we look at the adequacy of the diet overall throughout the day.

Conditional amino acids include: arginine, cysteine, glutamine, tyrosine, glycine, ornithine, proline, and serine.