BEAUTIFUL but DEADLY

1. A virus is an infectious agent made up of nucleic acid (DNA or RNA) wrapped in a protein coat called a capsid. 2. Viruses have no nucleus, no organelles, no cytoplasm or cell membrane—Non-cellular 3. This is why it does NOT belong to any kingdom. vs

Replication is how a virus spreads. A virus CANNOT reproduce by itself—it must invade a host cell and take over the cell activities, eventually causing destruction of the cell and killing it. (The virus enters a cell, makes copies of itself and causes the cell to burst releasing more viruses.) DNA/RNA is copied. DNA/RNA injected into cell. Virus attaches to cell. Step 3 Step 2 Step 1 Virus copies itself. Cell bursts (lyses) and releases new viruses. Step 4 Step 5

Certain viruses can only attack certain cell types Certain viruses can only attack certain cell types. They are said to be specific. Example: The rabies virus only attacks brain or nervous cells. Surface Markers Virus Receptor Sites It’s like the pieces of a puzzle. The ends have to match up so only certain pieces fit. Cell

A virus recognizes cells it can infect by matching its surface marker with a receptor site on a cell. Virus Surface Markers Cell Receptor Sites

Bacteriophage—viruses that infect bacteria Capsid (protein coat) inside contains either RNA or DNA 2. Flu (influenza), HIV DNA or RNA Surface Marker Capsid (protein coat)

THE FIVE VIRUSES MODELED IN LAB ACTIVITY: Animals, plants and bacteria are all susceptible to viruses. Potato X HIV Adenovirus Tobacco Mosaic Bacteriophage

NANO CELLS: HOW BIG????

VIRAL VECTORS MOSQUITO Carrier of West Nile Virus. When fall arrives and temperatures decrease, the mosquito population consequently declines. However, migration season is shortly after, and as birds and mosquitos travel, they bring the virus with them. There are currently 110 species of infected birds, and the number of mosquito species who can transmit the virus has jumped from one to eight. BATS Carrier of the Rabies virus. It is a preventable viral disease of mammals most often transmitted through the bite of a rabid animal. The overwhelming majority of rabies cases reported to the Centers for Disease Control and Prevention (CDC) each year occur in wild animals like raccoons, skunks, bats and foxes.

Tobacco leaves and tomatoes infected with Tobacco Mosaic Virus NON-VECTOR VIRAL DISEASES Tobacco leaves and tomatoes infected with Tobacco Mosaic Virus POTATO X VIRUS