Viruses• Non-living - does not grow, eat, release waste,
or breathe.
• Is able to reproduce, but only when inside a host (the cell that a virus enters)
• 100 times smaller than bacteria
Virus -• A nucleic acid core encased in a protein coat that
can infect cells and replicate within them
REPRODUCTION
1. Viruses cannot reproduce on their own
2. They need a host cell to do all the work
3. It is a five step process called the
Lytic Cycle that ends in the host cells death.
Viral Reproduction - Lytic Cycle1. Attachment - Virus attaches to the Host cell
2. Penetration - Virus injects its RNA or DNA
3. Replication - Host cell makes many copies of the viral RNA or DNA
4. Assembly - Host cell builds new viruses
5. Lysis - New viruses breaks out of host cell -killing it – to attack other hosts
1. Attachment2. Penetration3. Replication of DNA4. Protein assembly - making new viral coats5. Lysis
4
352
1
MOBILITY
• Viruses do NOT move on their own
• Transferred by water, air, food, human contact
MOVEMENT
VIRAL DISEASES
Pathogenic (disease causing)
• Flu
• Hepatitis C
• Mumps
• Measles
• Ebola
• Polio
• HIVPolio
How are viruses treated?
• Antibiotics/medicines do NOT work on viruses
• About the only treatment is to drink plenty of fluids and bed rest. Some medicines may improve symptoms such as aspirin for fever.