Viruses

By: Spencer Lovejoy & Peter Valhouli-Farb

Viruses

• Viruses are not alive

• By themselves the can not move, grow, or reproduce

• Smaller then the smallest bacteria

• Two types of viruses

• Viruses have two types of Nucleic Acid

• In Latin, virus means “Poison”

Structure of a Virus (HIV)

•Glycoproteins (Receptor Site)

•RNA (Inside)

•Protein (Inside the shell)

•Lipid Bilayer

Reproduction

• Before a virus can replicate it must enter a host cell

• A virus recognizes and attaches to a host cell when one of its proteins interlocks with the receptor cite on the plasma membrane of the host cell.

• The attachment protein is found in the capsid which is inside or the envelope which is outside of the virus.

• Once attached to the plasma membrane of the host cell, the virus enters the cell and takes over its metabolism. Only then can the virus replicate.

Plant Viruses

• First plant virus recognized was the Tobacco Mosaic Virus

• There are more then 400 known plant viruses

• Cause as many as 1000 plant diseases.

• Some plant viruses are good for plants

Human Viruses

• Can be spread by: Intercourse, human fluids, lakes or ponds, germs, or can run down in the family (AIDS and HIV)

• Very few human viruses are deadly

• Human viruses can replicate in dead cells

• UV light can destroy a human virus or viruses

Images

Summary

• Viruses are not living

• Can only replicate with host cell

• Human and plant viruses

• Some viruses are deadly

• Consists of lipid bylayer, protein shell, and glycoproteins

• More than 800 known plant and human viruses