Viruses

What is a virus? A virus is: NON-LIVING particle Made of a protein coat and DNA or RNA Smaller than bacteria ( nm)

Why is it non living? Reasons 1) A virus is not made out of cells 2) A virus can not reproduce on its own 3) No energy required

What do they do? Infect specific cells and get those cells to make more copies of it PlantsBacteriaAnimals

Growth & Reproduction Nonliving = no energy required Can not grow or make proteins by itself Must infect a host cell Steps to reproduction: 1.Identify specific host cell using protein receptors (lock and key) 2.Enter host cell 3.Insert DNA or RNA 4.Host cell reads instructions and makes more viruses 5.Viruses leave and destroy cell

Viral Reproduction Lytic Cycle –Virus infects cell and integrates into DNA Virus takes over cell processes Makes multiple copies of viral parts Lyses (pops) the host cell

Viral Reproduction Lysogenic Cycle –Virus infects cell and integrates its DNA into host’s DNA The Viral DNA replicates (gets copied) as the cell replicates If virus is activated, it enters into Lytic Cycle –Inserted viral DNA may disrupt cell processes which can be cancerous

Viral Reproduction Virus Attaches Injects DNA Viral DNA takes over host cell protein machinery New virus parts made & assembled New viruses leave & kill host cell by Lysis (popping) Viral DNA integrates into host cell DNA Viral DNA duplicates with the host cell Does not kill cell Lytic CycleLysogenic Cycle If activated, dormant virus can enter the Lytic cycle

Are viruses bad? Yes! All viruses destroy their host cells

How do they make you sick? They insert their DNA or RNA into yours. Your cell makes more viruses until it is destroyed

How can you stay safe? Use a vaccine Wash hands

Any cures? NONE! Antibiotics do not work!!!