Virus A pathogen that consists of a Nucleic Acid – (DNA or RNA) wrapped in a Protein Coat- (Capsid). Classification: Classified by the host Bacteriophage infects bacteria
Reproduction Occurs only in a host cell. 2 types: Lytic Cycle: Virus enters cell, makes copies of itself, and kills the cell. Lysogenic Cycle: hides in the DNA and replicates with the host cell until conditions allow it to enter the lytic cycle.
Lytic Cycle Steps: The virus attaches to a cell The virus inserts their genetic info into the cell The virus breaks down the cell’s genetic information and starts to produce virus parts The new virus parts are assembled The new viruses are cause the cell to lyse (burst)
Lytic Cycle
Lysogenic Cycle Steps Virus integrates its DNA into the DNA of the host cell The viral genetic information replicates along with the host cell’s DNA indefinitely. When conditions are favorable, the virus will switch to the Lytic cycle and start killing the host cell.
Lysogenic Cycle
Retroviruses Contain RNA as their genetic information. Named because they work backwards Normal: DNA – RNA – tRNA – Protein Retrovirus: RNA – DNA – RNA – tRNA – Protein (virus) (host cell) Example: HIV
Vaccine Injecting someone with a weakened form of a virus