Genetic Material: Either DNA or RNA

Can't replicate without a host cell

Can't divide by binary fission, Mitosis or Meiosis

Can't make energy (get it from Host cell)

Can't make their own Protein or Genetic material (steal it from host cell)

Intracellular Parasites

Size range from 10-300 nm

Can infect all Organisms

Genetic Material surrounded by Capsid or Protein coat (Small protein units called Capsomeres)

Some have an outer envelope

May also have tail, sheath and tail fibres

Type of genetic Material

shape and/or size of Caspid

Number of Capsomeres

Presence or absence of an envelope

Type of hosts it infects

Type of disease it produces

Target cell

Immunologic or antigenic properties

Is the spectrum of host cells the virus can infect

Mostly single host range

Rarely cross the hist range Barrier

Determined by

3 Major theories

Outer surface of virus interact with specific receptor sites on surface of potential host cell

Complementary component held together by hydrogen bonds

Interfere with the Phases of viral multiplication

May disrupt an enzyme or protein

May interfere with the synthesis of viral parts like DNA, RNA or Protein synthesis

Retroirus

Plant Virus

Bacteriophage

Animal Viruses

Oncogenic Viruses

Based on guideline by ICTV (International Committee on Taxonomy of Viruses)

Grouping based on

Names