•A virus is a non-cellular particle made up of genetic material and protein that can invade living cells.

•Capsid: The protein shell, or coat, that encloses the nucleic acid genome.

•Capsomeres: Morphologic units represent clusters of polypeptides,

•Envelope: A lipid-containing membrane that surrounds some virus particles. It is acquired during viral maturation by a budding process through a cellular membrane

• Virus-encoded glycoproteins are exposed on the surface of the envelope. These projections are called peplomers.

•Nucleocapsid: The protein–nucleic acid complex representing the packaged form of the viral genome.

•Structural units: The basic protein building blocks of the coat.  Is referred to as a protomer.