The Virus

What is a Virus? A small NON-LIVING particle that invades and reproduces itself inside a living cell.

Are Viruses Living?? Cellular Organization Contain similar chemicals Use energy to grow or respond Growth and development Response to surroundings Reproduction (multiply) X

Do viruses multiply the same way as other organisms? No Uses a host: A living thing that provides the source of energy for a virus. A mutation in the H1N1 influenza A virus, termed the SR polymorphism, enhanced replication of the virus in humans. (Image courtesy of NIGMS) Acts like a parasite: Organisms that live on or in a host and causes harm to the host

Which of the Six Kingdoms do Viruses Infect? Archaebacteria Protists Plants Yes Yes Yes Eubacteria Fungi Animals Yes Yes Yes Yes – They infect all living Organisms Each kingdom has its own set of viruses

Viruses also invade specific areas of an organism!! Cold virus invades the nose and mouth Hepatitis virus attacks the liver Tobacco Virus – the Tobacco Leaf

Some Pictures of Viruses Tomato mosaic Virus Bubo virginianus Ebola virus This is a bacteria

Viruses you might have heard of: Influenza causes common flu Polio causes muscle weakness and paralysis Herpes causes Mononucleosis (mono) and chicken pox HIV causes AIDS Hepatitis cause liver malfunction Measles causes a body rash and flu-like symptoms Ebola Tomato mosaic

Viruses (4 min)

Size and Shape of Viruses Viruses come in different shapes and sizes. Their shape determines what they will infect. How big are they Click http://learn.genetics.utah.edu/content/begin/cells/scale/

Structure of Viruses Genetic Material Outer Protein Coat Protect the virus Acts as the key to lock onto a living cell The protein in the outer coat must match the proteins in the cells membrane

How Viruses Multiply Outer Protein coat locks onto specific host cell surface. Virus’s genetic material is injected in host cell and takes over cell’s function. Active virus – immediately Hidden virus – delayed Cell Produces Virus’ protein and the genetic material over and over and then assembles new viruses. Cell becomes full and bursts.

How are Viruses used to help us? Gene Therapy In Gene Therapy viruses are used because they can attach to a host cell and inject good DNA into an infected cell. Scientists use viruses to change the genetic makeup of these cells.

Understanding Viruses Part 1 and 2 (54 min) https://app.discoveryeducation.com/player/view/assetGuid/2D21C2FF-648A-4187-82B5-C3DAA38D3224