VIRUS

VIRUS A minute, biologically active particle made up of a nucleic acid core (as a genetic material) and a protein covering (capsid) It is not a cell (not capable of carrying cellular processes).

Obligate intracellular parasites Virus Biological particle Capsid - protein Acellular level Obligate intracellular parasites

Classification As to their host cells - plant viruses - bacterial viruses - animal/human viruses B. As to their symptoms - virulent – causes a disease - temperate – does not cause a disease immediately C. As to nucleic acid core - DNA viruses - RNA viruses

Structure: Capsid – protein coat Membranous envelope- surrounds the protein coat Nucleic acid core – hereditary material

Viral Replication (Reproduction) 1. Lytic Cycle - the virus replicates and ruptures the host cell. 2. Lysogenic Cycle - the viral genetic material is incorporated into the host’s DNA. - killing of the host cell is not necessary

Common Viral diseases Warts 6. polio Chicken pox 7. colds Influenza 8. Rabies Mumps 9. Viral 5.Measles pneumonia

Other viral . . . . HIV – AIDS - retrovirus - reverse transcriptase - RNA – DNA - RNA

Small pox

Polio

Measles

Mumps