Bacteria and Viruses

1. Bacteria and Viruses Chapter 19

2. Some suggested topics: • Lyme disease • Tetanus • Tuberculosis • Bacterial meningitis • Strep throat • Common cold • Influenza • AIDS • Chicken pox • Hepatitis B • West Nile • Herpes • H1N1 • Anthrax • Botulism • Cholera • Diphtheria • Listeriosis • Pneumococcal pneumonia • Scarlet fever • Syphilis • Typhoid fever • HPV • Measles • Infectious mononucleosis • Mumps • Rabies • Rubella • SARS • Smallpox • Viral meningitis • Viral pneumonia • Gonorrhea • Leprosy • Pertussis (Whooping cough)

3. Bacterial and Viral Infections Presentation • Pictures/video of the pathogen • Transmission (how it gets into the host) • Symptoms (how it affects the host) • Treatment (how we “fight” it) • Value: 20 pts (5 each) • Due date: Wednesday, April 6th at the beginning of class (be ready to present!)

4. Why are bacteria so important to life on Earth? • Producers: photosynthesis for food chain) • Decomposers: (break down/recycle nutrients) • Nitrogen fixers: (convert nitrogen gas into “useful” forms for plants and the food chain)

5. Importance for humans: • Human uses: • A) sewage treatment (purifies water, products for fertilizers) • B) Food and beverage production • C) Digest petroleum (cleaning up small oil spills) • D) Make drugs and chemicals through genetic engineering • E) Enzymes for medicine

6. Human-Bacterial Symbiosis: • Name E. coli is derived from the fact that they live in our colon (large intestine). • We give them: • A) a warm, safe home • B) plenty of food • C) free transportation • They give us: • A) some vitamins we need • B) protection from virulent strains of bacteria • (see news article)

7. Questions from Chapter 19: 1. What are two ways bacteria produce disease? 2. What are antibiotics and how do they prevent disease? 3. a) What does the word “virus” mean? b) Describe the events that lead to the study and understanding of viruses. 4. What are the parts of a virus? 5. What are bacteriophages? 6. Draw diagrams of the 2 types of viral infection. (page 481) 7. a) What’s a retrovirus? b) Explain their name. 8. What are vaccines and how do they prevent disease?

8. Answers to the questions: 1. i) Destroy host cells for food (Ex: tuberculosis). ii) Release of toxins interferes with normal bodily functions (Ex: strep throat, diphtheria). 2.-Compounds that block the reproduction and growth of bacteria; stopping or slowing infection. -Have been responsible for dramatic increases in life expectancy over the last few centuries. Eyes of Nye: Antibiotics

9. Tobacco Mosaic Virus Story: 3. a) “Virus” is the Latin word for “poison”. b) –In 1892 farmers’ tobacco plants dying -yellowing pattern (mosaic) on the plant leaves -Disease-causing juice is isolated from plants -Nothing seen in juice under microscope -Some unknown thing (too small to be bacteria) is therefore causing the infection)

10. Parts of a Virus: 4. i) nucleic acid (genes encoded by DNA or RNA) ii) protein coat surrounding the genes, called a capsid 5. Viruses that infect bacteria (“phage” means “eat”)

11. Stages of Viral Infections: 6. i) Lytic: -Takes over host cell and uses it to make new viral parts (copy itself) - Host cell bursts open, releasing more viruses ii) Lysogenic: -Inserts/incorporates its DNA into host chromosome -This piece of viral DNA is called a provirus -Lies dormant for a while, but then… -At some point, the provirus exits the host chromosome and enters the lytic cycle. Ex: HIV Lysogenic and Lytic Cycles (See page 481 of text)

12. Retroviruses and Vaccines: 7. a) RNA is their genetic material (not DNA). b) “Retro” = “backwards”, refers to these viruses doing the reverse of what normally happens. Normal: DNA RNA  Protein, but: they go from RNADNA instead. 8. -Preparation of weakened or killed pathogens. -Prompts the body to produce immunity to disease. *See Edward Jenner story (smallpox).

13. Bacteria + virus bingo vocabulary: • Prokaryotes • Bacilli • Cocci • Spirilla • Obligate aerobes • Obligate anaerobes • Facultative anaerobes • Binary fission • Conjugation • Endospore • Nitrogen fixation • Virus • Capsid • Bacteriophages • Lytic infection • Lysogenic infection • Prophage • Retroviruses • Pathogens • Vaccine • Antibiotics • Chemoheterotrophs • Photoheterotrophs • Photoautotrophs • Chemoautotrophs • Tobacco mosaic virus • E. coli • Edward Jenner

14. Are viruses alive? • Using the information on page 482-483, as well as your own opinion, write me a short paragraph telling me whether or not you think viruses should be considered living things or not. • Mr. Jessome’s idea of a short paragraph: -More than 2 sentences, but less than 10. • Mr. Jessome’s idea of fun: -Writing a short paragraph about whether or not viruses should be considered living things.

15. Preventing bacterial infections: a) Sterilization by heat: Too hot  kills bacteria b) Disinfectants: Chemicals  kills bacteria c) Food processing: Cool temps  slows bacterial reproduction Antibiotics: -Work for bacterial infections, but not for viruses “anti” = “against” + “biotics” = “living things” Hmmmmmmmmmmmmmmmmmmmmmmmm….

16. Chapter Review questions: • Page 493: #’s 1 -10 (But not #4-You’re welcome) • Also: #’s 12, 14, 17, 18, 20, 21, 25 • Page 495: #’s 1-5, 7, 8