VIRUSES

SIZE of VIRUSES  Viruses are so small they must be measured in “nanometers”  1,000 nanometers = 1 micrometer  1,000 micrometers = 1 millimeter  10 millimeters = 1 centimeter  10,000,000 nanometers = 1 centimeter

SIZE of VIRUSES  Bacteria are 1/10 to 1/20 the size of cells from the organisms found in the other 4 kingdoms.  The average bacterium is 1,000 nanometers long.  Viruses are 20 to 250 nanometers long.

Some Common Viruses PoliomyelitisYellow Fever Influenza

Some Common Viruses Bacteriophage Mumps HIV

Other Diseases Caused by Viruses:  Diptheria,  Small Pox  Ebola  Avian Flu  SARS  Mad Cow Disease  And MANY Others!

Types of Viruses:

Parts of A Virus  Capsid – the covering made of protein and can take many different shapes  Genetic Material – either RNA or DNA  Envelope (Some Viruses)

Living or Non-Living?  Cannot Grow  Cannot Respond to the Environment  Cannot Reproduce Independently

Virus Replication  Attachment

Virus Replication  Injection  The Virus pushes its Genetic Material into the host cell.

Virus Replication  Production  The Virus’s Genetic Material forces the host cell to make the parts for new viruses.

Virus Replication  Assembly  The virus parts are attached to create new viruses ready to invade other cells.

Virus Replication  Release  The newly created viruses burst out of the cell to go infect new cells. This obviously kills the host cell!