Viruses, Viroids & Prions

General characterristics

Viruses are infectious bodies that are made up of different nucleic acids in a protien coat, some viruses also have a outer envelope composed of fatty materials and protiens. Viruses range in size from 10- 200 nanometers, and can be seen only with an electron microscope. Viruses use a host cell to reproduce. Each type of virus attacks a specific type of cell, for example the AIDS virus attacks T4 cells. Viruses cannot properly carry out lifes functions outside a living cell of a plant, animal, or bacteria. they have many different shapes including rod shaped and spherical.

Viral Reproduction

Viruses reproduce by infecting a host cell with its nucleic acid,. this then allows the virus to take control of the cells activities and allows it to use the cells DNA or RNA synthesising ablility to reproduce its core and uses the cells ability to replicate protiens to replicate the viruses outer covering. The virus may then cause the cell to burst, releasing the virus to infect other cells. The new viruses may also be released by budding off the cell membrane. the virus may also not replicate and remain dormant in the host cell.

Viron & Prion

VIRON- the extracellularinfective form of a virus consisting of the outer protien layer, the inner nucleic acid core, and (in some cases) the fatty membrain surrounding the capsid.
  PRION- smallest known infectious agent, probibly composed soley of protiens, contains no identifyable genetic material; cause of several neurological diseases.

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