2. Viruses

3. Viruses are very small

4. Anatomy of a Virus

5. Viral Genomes Viruses may have Double stranded DNA Single stranded DNA Double stranded RNA Single stranded RNA Viruses are called either a DNA or RNA virus depending on their type of genome

6. Some Viruses Which Infect Humans Class of virus (type of genome) Name of VirusExamples Double stranded DNAPapovavirus Herpesvirus Papilloma (warts, cervical cancer) Herpes simplex I (cold sores), Herpes simplex II (genital sores), Varicella zoster (chicken pox) Single stranded DNAParvovirusRosoela Double stranded RNAReovirusDiarrhea, mild respiratory disease Single stranded RNAPicornavirus Togavirus Rhabdovirus Paramyxovirus Orthomyxovirus Retrovirus Rhinovirus (common cold) Rubella, Yellow Fever, Encephalitis Rabies Measles, mumps Influenza HIV (AIDS virus)

7. Virus Reproduction Do viruses have o A nucleus? o Enzymes for metabolism? o Ribosomes for protein synthesis? Viruses can reproduce only within a host cell

9. Virus Reproduction The Lytic Cycle Culminates in the death of the host cell The Lysogenic Cycle Replication of the viral genome without destroying the host cell