Virus Notes Kingdom journal pages 9-13

Definition non-living particle that is composed of nucleic acids enclosed in a protein coat

Unique Traits Do not show all characteristics of life (growth, energy use, homeostasis, etc), so are considered non-living Must replicate inside a host cell, which can be any living organism. Viruses though are specific for each host. Vaccines are used to prevent future viral infections by giving a dead or weak version of the virus to cause the body’s immune response to create antibodies against that virus.

Most Common Human Viruses HIV--AIDS Adenovirus—common cold Influenza—Flu Herpes Poliovirus—Polio Hepatitis B and HPV are viruses that can cause mutations that lead to cancer.

Means of Reproduction Must occur within a host cell. The virus takes over and makes the cell build all the new viruses. Lytic cycle—occurs immediately after infection Lysogenic cycle—waits within host DNA

Viral Structure and Function Genetic Material/RNA or DNA—code for making new viruses Capsid—protein coat that protects genetic info Envelope—helps to infect host, not present on all viruses (projects help the virus to blend, so the body does not create an immune response)

Means of Reproduction Must be within a host cell Lytic cycle—virus infects a cell and immediately takes over the cell. The host copies the viral genetic code, makes new protein coats, and assembles the new viruses until they burst out the cell. Lysogenic cycle—virus infects cell, but its DNA waits within host’s DNA until the cell is under stress and then switches to the lytic cycle.