Viruses

Viruses

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//By Jeff Kitchen //

= = = = = = =What is a Virus? = -Viruses are small nonliving particles of nucleic acid, protein and sometimes lipids.

=Structure of Viruses = -Viruses are protected by a protein coat called a capsid. There is DNA or RNA located inside the virus.

=RetroVirus = -A retrovirus is a virus made of RNA. This makes them very likely to change because RNA is very unstable compared to DNA which cannot just last longer but can be identified easier because it is not constantly changing.



=Bacteriophage = -A bacteriophage is a virus that infects bacteria.

=Viruses Come in Many Shapes and Sizes =

= = =Virus Reproduction = -Viruses reproduce by infecting living cells. One type of infection is a lytic infection. Once inside the living cell the virus can make copies of itself causing the cell to burst. Another way of reproduction by infection is called a lysogenic infection in which the host cell makes copies of the virus indefinitely. The difference between a lytic and a lysogenic infection is that in a lysogenic infection the virus does not lyse the host right away.

=Prophage = <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 120%;">-A prophage is viral DNA embedded into the host DNA.

=<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 120%;">Facts About Viruses = <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 120%;"> -Viruses are only visible with and electron microscope <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 120%;"> -Viruses are non-living <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 120%;"> -Viruses cannot be affected by antibiotics <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 120%;"> -The only known way to stop a virus is by receiving a vaccination - an injection of a weakened or mild form of a pathogen to produce immunity.

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 120%;">Here is an animation about a how a virus infects a cell in the body...

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 120%;">http://www.courses.fas.harvard.edu/~biotext/animations/viralinfection.html