1. Viruses

2. What is a Virus? Nonliving particle
Strand of hereditary material surrounded by a protein coating.

3. How do Viruses Multiply?
Need a host to replicate.

4. Active Viruses Make new viruses within a host cell.
Kills the host cell.

5. Latent Viruses
When the virus enters the cell, its hereditary material becomes part of the cell’s hereditary material.
The viral hereditary material is copied when the cell multiplies.
Eventually, the virus becomes active.

6. Are viruses host specific?
Some viruses only attack certain species or certain tissues within a host.
Others can infect a group of species.
Virus must match a “host site” in order to attack a host.

7. Bacteriophages
Viruses that infect bacteria.

8. Vaccines Made from weakened viruses that can no longer cause diseases.
Antiviral drugs are now also available for limited use.

9. How does your body fight viruses?
When infected, your body produces interferons.
Interferons cause noninfected cells to produce protective coverings.

10. Viruses and Gene Therapy
Correct genetic material is inserted into a virus.
The virus than infects cells with genetic abnormalities.