1. Chapter 19 Pgs 485-490

2.  Bacteria produce disease in one of two general ways. Some bacteria damage the cells and tissues of the infected organism directly by breaking down the cells for food.  Tuberculosis—is inhaled through the lungs, where it destroys the lung tissue.  Other bacteria release toxins (poisons) that travel throughout the body interfering with the normal activity of the host.  Streptococcus (strep throat)—releases toxins into the bloodstream: can also cause scarlet fever.

3.  Many bacterial diseases can be prevented by stimulating the body’s immune system with vaccines.  Vaccine—preparation of weakened or killed pathogens  Prompts the body to produce immunity to the disease  If a bacterial infection does occur, a number of drugs can be used to attack and destroy the invading bacteria.  Antibiotics—compounds that block the growth and reproduction of bacteria.

4.  Various methods 1. Sterilization by Heat—most bacteria cannot survive high temperatures for a long period of time, so most can be killed by exposure to high heat. 2. Disinfectants—chemical solutions that kill pathogenic bacteria. Overuse increases the likelihood that common bacteria will evolve to become resistant to them. 3. Food Storage—Food stored at low temperatures will stay fresh longer because the bacteria will take longer to multiply.

5.  Like bacteria, viruses produce disease by disrupting the body’s normal equilibrium.  In many viral infections, viruses attack and destroy certain cells in the body, causing the symptoms of the disease.  Cannot be treated with antibiotics.  Best protection lies in prevention.

6.  Viruses produce serious animal diseases as well.  Foot-and-mouth disease that swept through Europe in the late 1990—thousands of cattle were destroyed.  Some animal viruses can cause cancer.

7.  Many viruses infect plants.  Serious threat to many agricultural crops.  Many plant viruses are spread by insects.  Feeding action of an insect pest often provides a perfect opportunity for viral infections to spread.

8.  Viruslike particles that can also cause disease 1. Viroids—cause disease in plants 1. Single-stranded RNA molecules that have no surrounding capsids 2. Viroids enter an infected cell and direct the synthesis of new viroids 3. Then disrupt the metabolism of the plant cell and stunt the growth of the entire plant 2. Prions—cause disease in animals 1. Cause disease by forming protein clumps 2. Contain no DNA or RNA 3. Strong evidence that mad cow disease is caused by prions

9.  http://www.virology.net/big_virology/EM/polio1.gif http://www.virology.net/big_virology/EM/polio1.gif  http://ledaomd.files.wordpress.com/2008/10/hand-foot- mouth.jpg http://ledaomd.files.wordpress.com/2008/10/hand-foot- mouth.jpg  http://www.ourmed.org/images/1/11/Hand_foot_mouth_di sease.jpg http://www.ourmed.org/images/1/11/Hand_foot_mouth_di sease.jpg  http://images.dailytech.com/nimage/10351_plant_virus.jpg http://images.dailytech.com/nimage/10351_plant_virus.jpg  http://www.mcb.uct.ac.za/tutorial/Image62.gif http://www.mcb.uct.ac.za/tutorial/Image62.gif  http://www.peta.org/cfs- filesystemfile.ashx/__key/CommunityServer-Components- SiteFiles/Peta-Images-Main-Sections- Living/200_2D00_LivingVegMadCow.jpg http://www.peta.org/cfs- filesystemfile.ashx/__key/CommunityServer-Components- SiteFiles/Peta-Images-Main-Sections- Living/200_2D00_LivingVegMadCow.jpg  http://www.ars.usda.gov/sp2UserFiles/person/2273/viroids 1a.jpg http://www.ars.usda.gov/sp2UserFiles/person/2273/viroids 1a.jpg