What is a Virus?
Polyhedral Virus
consist of nucleic acid surrounded by a polyhedral shell or capsid, usually in the form of an icosahedron.
Helical Virus
consist of nucleic acid surrounded by a hollow protein cylinder or capsid and possessing a helical structure
Spherical Virus
consist of nucleic acid surrounded by either a helical or polyhedral core and covered by an envelope
Complex Virus
have neither helical nor polyhedral forms, are pleomorphic or irregular shaped, or have complex structures