Peptides are short polymers of amino acid which are linked by peptide bonds, the covalent chemical bonds formed between two molecules when the carboxyl group of one molecule reacts with the amino group of the other molecule.
These are distinguished from proteins on the basis of size, typically containing fewer than 50 monomer (AA) units. The shortest peptides are dipeptides, consisting of two amino acids which are joined by a single peptide bond.
There are also tripeptides, tetrpeptides, etc. Amino acids which have been incorporated into a peptide, is termed residues. Every peptide has a N-terminus and C terminus residue on the ends of the peptide.
Proteins are large organic compounds that are made up of amino acids arranged in a linear chain and joined together by peptide bonds. Proteins are the most abundant components of biological cells. They exist functioning such as enzymes, hormones, structural element and immunoglobulin.