Describe some of the modifications that polypeptide chains undergo before becoming functional proteins

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.

Cells of an organism tell each other when predators are near.

Except hold on to his or her beliefs even if there is no evidence for those beliefs.