Presentation on theme: "VIRUSES. Virus- a tiny, nonliving particle that enters and then reproduces inside a living cell Characteristics of viruses: Not cells Do not use energy."— Presentation transcript:
Virus- a tiny, nonliving particle that enters and then reproduces inside a living cell Characteristics of viruses: Not cells Do not use energy Do not make food or take in food Do not produce waste Can only multiply when inside a cell
Host- an organism that provides a source of energy for a virus or another organism Parasite - an organism that lives on or in a host and causes it harm Viruses act like parasites and almost always kill the cells that they multiply in
Viruses attach to cells using a “lock and key” method Each virus has unique surface proteins these proteins allow the virus to attach to certain host cells
HOW VIRUSES MULTIPLY
1. Adsorption - virus binds to the host cell. 2. Penetration - virus injects its genome into host cell. 3. Viral Genome Replication - viral genome replicates using the host's cellular machinery. 4. Assembly - viral components and enzymes are produced and begin to assemble. 5. Maturation - viral components assemble and viruses fully develop. 6. Release - newly produced viruses are expelled from the host cell.