Virus The Papillomavirus is a DNA virus that causes warts. These infectious particles are small, about 15 nm in diameter The Adenovirus is a DNA virus that causes colds and "pink eye".

Viral diseases in humans HIV immune system Chicken pox skin Common cold Respiratory system Influenza respiratory system Measles skin Mumps Salivary Tissue Polio Nervous System

Definition A virus is a small infectious piece of material— much smaller than a fungus or bacterium—that must invade a living cell to reproduce (replicate).

Adenovirus http://web.bham.ac.uk/can4psd4/adeno.gif http://www.pacisa-giralt.com/cards/_rct/a/0018.jpg

www.rkm.com.au/imagelibrary/ http://micro.magnet.fsu.edu/cells/viruses/images/bacteriophage.jpg

The polio virus, left, once crippled millions The polio virus, left, once crippled millions. Courtesy of the MicrobeLibrary.org; © Jean-Yves Sgro, University of Wisconsin. The T4 bacteriophage, middle, is a virus that invades bacterial cells. Courtesy of the MicrobeLibrary.org; © Dennis Kunkel. Gold clusters bound to the knob protein of Adenovirus, right. Courtesy of Brookhaven National Laboratory. http://www.microbeworld.org/htm/aboutmicro/microbes/types/virus.htm

Virus Basics not living but contain genetic material lack all cell structures can reproduce ONLY in living cells and do not carry out any other life processes. they survive by using the cell’s “machinery” to reproduce

Virologist Person who studies viruses

How Can you catch a virus? 1. Through the air 2. Through direct contact with body fluids (blood, saliva) 3. Through food.

More basics the Latin word for poison is virus 1892 a Russian biologist discovered the first virus (a plant virus) has genetic material (DNA or RNA) wrapped in a protein coat tobacco mosaic virus

What is a bacteriophage? It is a bacteria “eater” Since the invention of the electron microscope, it is known as a virus. (we’ll use microviewers in class)

Size of common viruses Name Size Cowpox and smallpox 250 nm Influenza, mumps 100 nm Tobacco mosaic virus 65 nm Yellow fever virus 22 nm Polio 12 nm Over 2 million cold viruses could fit on a period at the end of a sentence

Nanometer to meter {scientific notation} Size Conversion 250 nm 250 x 10-9 100 nm x 10-9 65 nm 22 nm 12 nm 1 nm= 0.000000001 meters

What is a vaccine? - It causes the body to attack and defend. - It is a weakened virus or the virus has altered its RNA/DNA - It causes the body to attack and defend.

How do viruses infect cells ? The virus takes control of the cell machinery The cell “forgets” its own needs and works for the benefit of the virus. There are 4 steps to how a virus duplicates itself once it attaches to a cell :

Attach Invade Copy Release 1 2 3 4

More on Active Viruses Attach a specific virus attaches to the surface of specific cell. Invade The genetic material of the virus is injected into the host cell Copy The nucleus of the host cell begins copying the genetic material of the virus Release The cell bursts and a lot of new viruses are released. The new virus cells go on to infect other cells.

Living Versus Non-living