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Viruses and Bacteria

Viruses and Bacteria. What do these diseases have in common?. Mumps http://www.kcom.edu/faculty/chamberlain/Website/lectures/lecture/IMAGE/MUMPS.GIF. Hepatitis B http://www.idph.state.il.us/images/hepatitisb.jpg. Measles http://www.idph.state.il.us/images/measles.jpg.

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Viruses and Bacteria

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  1. Viruses and Bacteria

  2. What do these diseases have in common? Mumps http://www.kcom.edu/faculty/chamberlain/Website/lectures/lecture/IMAGE/MUMPS.GIF Hepatitis B http://www.idph.state.il.us/images/hepatitisb.jpg Measles http://www.idph.state.il.us/images/measles.jpg Polio http://www.immune.org.nz/site_resources/Professionals/Diseases/Polio/Polio.jpg

  3. It looks alive, acts alive… but its not! • Viruses are not living things. They differ from living things in several ways: • They need to be inside a living organism to reproduce themselves. • Outside the cell, they have no metabolism. • They do not have cell parts. (i.e. nucleus, mitochondria, etc) • They are composed of only a nucleic acid (DNA or RNA) inside a protein capsule.

  4. Viral Reproduction • In order to reproduce: • A virus attaches to a host cell. • The virus injects the cell with its nucleic acid. • The viral nucleic acid commands the cell to make more viral protein and nucleic acid. • The cell then ruptures, releasing hundreds of new viruses. http://porpax.bio.miami.edu/~cmallery/150/gene/sf11x1virus.jpg

  5. Retroviruses…No, they aren’t from the 70’s! • These are viruses that store their genetic information as RNA. • Their genetic information is copied backward-from DNA to RNA. • Ex: some types of cancer & AIDS http://international.ucla.edu/cms/images/hiv_virus.jpg

  6. They infect their host cell. They produce a DNA copy of their RNA. It may remain dormant for varying lengths of time. How it works…… http://hiv.buffalo.edu/./images/hiv_virus_in_action.jpg

  7. Your friendly bacteria • Bacteria are living, unicellular prokaryotes. • Divided into two kingdoms: Eubacteria and Archaebacteria • Heterotroph or autotroph (most use chemosynthesis). • Types of Bacteria are classified based on their shape, type of cell wall, and movement. • Bacteria have three basic shapes: • Bacilli – rod-shaped • Cocci – spherical • Spirilla – spiral http://fig.cox.miami.edu/~cmallery/150/proceuc/c27x3proc_shapes.jpg

  8. Eubacteria have peptidoglycan and certain specialized lipids in their cells walls that are not present in Archaebacteria. • Gram staining is used to differentiate types of Eubacteria. • Those having thick cell walls will absorb more of the dye and appear dark purple (Gram positive). • Those having thinner cell walls will absorb less of the dye and appear pink (Gram negative). http://bioweb.uwlax.edu/bio203/s2008/jaedike_alic/grainpositive.jpg http://www.asm.org/Division/c/photo/gc1.JPG

  9. Bacteria Growth and Reproduction http://porpax.bio.miami.edu/~cmallery/150/gene/sf9x3box.jpg • Bacteria reproduce in two main ways: • Binary fission – when a bacteria grows to double its original size, it copies its DNA and divides, producing two identical cells. • Conjugation – a hollow bridge is formed between 2 bacteria and genes are transferred from one cell to the other. • This creates genetic diversity within the population. • Spore formation – when conditions are unfavorable (lack of food, drought) that encloses its DNA and part of its cytoplasm in a spore. • When conditions are better, the spore will germinate, and the bacterium will continue to grow. http://www.emc.maricopa.edu/faculty/farabee/BIOBK/69091a.jpg

  10. They’re not all bad…. • Bacteria are most widely known for causing diseases such as strep throat, tetanus, meningitis, and tuberculosis. • However, most bacteria are very useful: • E. coli helps us digest our food & make vitamins for humans. • Many are important decomposers in our ecosystem. • Rhizobium provides plants with nitrogen. • A few bacteria are used to clean up small oil spills in the ocean.

  11. Vaccinations • A weakened form of the pathogen (virus/bacteria) is used to stimulate the production of antibodies. • However, bacteria and viruses have very high reproductive rates, which result in many mutations. • Thus, bacteria and viruses evolve quickly, often requiring a different vaccine every year. http://www.biojobblog.com/vaccination%5B1%5D.JPG http://www.biojobblog.com/vaccination(5).jpg

  12. There are two types of vaccines (immunities): • Active – person is injected with the actual pathogen, and immune cells make their own antibodies against the disease, immunity is permanent • Passive – person is injected with antibodies that fight the disease, but immunity is temporary http://www.iavi.org/viewpage.cfm?aid=1682

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