A polypeptide is imagined as a line, the right end represented by the last amino acid and the left end represented by the first amino acid.
The first amino acid is also called as N-terminal amino acid and last amino acid is called C-terminal amino acid .
The different amino acid are attached through -CO-NH bond called peptide bond or amide bond.
Peptide bond is formed when a molecule of water is removed during a reaction between the amino group of one amino acid and the carboxyl group of another amino acid .
Removal of water is known as condensation and the bond formed is called peptide bond .