Polypeptide chains undergo some modifications before they become fully functional. Some of these modifications include: proteolytic cleavage, lipidation and glycosylation. Proteolytic cleavage refers to the removal of some amino acids from a polypeptide chain by proteases in order for the protein to become active. An example of a substance that is modified through this process is insulin.
The mass is increased as two things are added together so the two masses of the two substances are added together.
primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide.