Kingdom for Virus? Where do viruses belong?
Are Viruses Living or Non-living? Characteristics of life VirusCell Growth Homeostasis Metabolism Mutation Nucleic Acid Reproduction
Are Viruses Living or Non-living? Characteristics of life VirusCell GrowthNoYes HomeostasisNoYes MetabolismNoYes MutationYes Nucleic AcidDNA or RNADNA ReproductionOnly with hostCell Divison
Viral structure : Capsid: Protein Coat DNA or RNA for replication Adsorb-tion site Host specific May have a envelope
Bacteriophage Bacteria “eating” virus Virus uses the bacteria as a host For viral replication
Example: Plant Peach Virus 5.Virus can infect Plants Fungi Animals Bacteria Protists
Viral Replication Lytic cycle Viral DNA is injected into host cell Contains instructions needed to make more viruses Host cell replicates viral DNA and makes the viral capsids (protein coats) New viruses are assembled inside host cell Cell bursts open releasing new viruses
Lytic Cycle (Replication) of a Virus 1.Adsorption of virus onto the host 2. Insertion of Virus DNA into host cell 3. Replication of Viral DNA 4. Assembly of protein coat 5.Lysis of Host cell Membrane & release Of virus
Lytic Cycle
Viral Replication:
Viral Replication Lysogenic cycle Viral DNA is injected into the host cell Vial DNA inserts itself into the host’s DNA Remains inactive for days, months, or years As the cell reproduces, more cells are produced that have the viral DNA in them Eventually, the virus will enter the lytic cycle
Transduction: Viral DNA becomes inserted Into the Bacteria DNA (1/100,000 )
Lysogenic Cycle
Viruses and Human Disease
Herpes Simplex:
Warts Are a Skin Virus!
Plantar Wart
Chicken Pox & Polio Virus
Chicken Pox and Polio Virus
Rabies virus Hepatitis B (Liver)
HIV Virus
Cow Pox Vaccination 1749 Acquired Immunization Artificial injection of a small amount of virus Body’s immune response makes antibodies
Emerging Viruses Ebola