Transcript Viruses
Viruses Three Learning Objectives. 1. What is a virus? 2. What are the two basic parts of a virus? 3. How do viruses reproduce? 1. What is a Virus? 1. A simple microscopic parasite that infects bacteria, plants, and animals. 2. Often a major cause of disease 3. Consist of a core of RNA or DNA surrounded by a protein coat. Did you write that down? They are not truly alive. Viruses can’t: metabolize nutrients produce and eliminate wastes Reproduce (unless they are inside another organism’s cells) They are not considered living cells. Some human diseases caused by viruses are: AIDS Hepatitis Chicken pox Flu (Influenza) Common cold Mononucleosis Fever blisters Polio Measles Smallpox Ebola Warts 2. What are the two basic parts of a virus? The two basic parts of a virus are: a small collection of genetic material (DNA or RNA) an outer protective protein coat called a capsid. 2. What are the two basic parts of a virus? The two basic parts of a virus are: a small collection of genetic material (DNA or RNA) an outer protective protein coat called a capsid. Did you write that down? Everyone knows Franklin D. Roosevelt was afflicted by a virus. In the summer of 1921 at the age of 39 he was stricken with polio. What was the worst viral epidemic in US History? Between the years of 1918-1919 In the US 675,000 people died, (43,000 servicemen mobilized for WWI died) Globally between 20 –40 million 3. How does a virus reproduce? As stated earlier a virus can only reproduce in a living cell. This complicated series of five steps is called the Lytic life cycle. Lytic life cycle 1. The virus attaches to a host cell. 2. The virus inserts its DNA into the cell. 3. The viral DNA takes over the cell's machinery. 4. The host cell produces more and more viruses. 5. The host cell splits open releasing the viruses which leads to the cells death. Lytic life cycle 1. The virus attaches to a host cell. 2. The virus inserts its DNA into the cell. 3. The viral DNA takes over the cell's machinery. 4. The host cell produces more and more viruses. 5. The host cell splits open releasing the viruses which leads to the cells death. Two examples of common viruses: Polio Common Cold Polio FAVORITE HANGOUT: Intestine and nervous system LIKES: Moving to the brain and spinal cord, where it can cause paralysis DISLIKES: The vaccine developed in 1954 that has tamed it throughout most of the world Common Cold FAVORITE HANGOUT: Mucus linings of the respiratory tract LIKES: DISLIKES: Body temperatures above 102, hand washing, Helpful cites Glossary: http://wwwmicro.msb.le.ac.uk/MBChB/VirGloss.html http://www.mansfield.ohiostate.edu/~sabedon/biol3025.htm http://www.microbeworld.org/htm/aboutmicro/microbe s/types/virus.htm http://www.microbeworld.org/htm/aboutmicro/microbe s/types/virus.htm