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Viruses

Viruses. 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

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  1. Viruses

  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 it’s 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 • They have no metabolism outside the cell • They do not have cell parts (e.g., nucleus, mitochondria) • They comprise only a nucleic acid (DNA or RNA) inside a protein capsule

  4. Structure of a virus Complete the diagram! Protein capsid DNA (or RNA) Tube http://mrsec.wisc.edu/Edetc/technologist/thumbnails/Matt/Virus_diagram.jpg Tail Fiber http://www.humanillnesses.com/images/hdc_0001_0001_0_img0008.jpg http://www.aidsactioncoalition.org/images/hiv_virus.gif

  5. Virus 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

  6. Retroviruses No, they aren’t from the 70s • These viruses store their genetic information as RNA • Example: HIV http://international.ucla.edu/cms/images/hiv_virus.jpg

  7. Archaea and Bacteria

  8. Archaea v. Bacteria Bacteria have peptidoglycan and certain specialized lipids in their cells walls that are not present in Archaea Bacteria live in the same environment as humans, some are anaerobic) Archaea live in EXTREME conditions (high pressure/ temperature, deep sea vents) Most are anaerobic!

  9. Kingdom Bacteria…your friendly neighborhood bacteria • Bacteria are living, unicellular prokaryotes. • Heterotroph or autotroph (most use chemosynthesis). • 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

  10. Structure of a Bacteria Complete the diagram! Cell membrane Cell wall DNA Ribosomes http://www.ou.edu/class/pheidole/General%20Bacteria.jpg

  11. Bacteria reproduction Bacteria reproduce asexually: Binary fission – a bacteria doubles in size; copies its DNA and divides, producing two identical cells. Spore formation – in unfavorable conditions (lack of food, water) bacteria form a capsule that encloses its DNA and part of its cytoplasm When conditions are better, the spore germinates and grows.

  12. 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. • 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.

  13. Vaccines http://www.biojobblog.com/vaccination%5B1%5D.JPG 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(5).jpg

  14. There are two types of vaccines (immunities): • Active immunity – person is injected with the actual pathogen, and immune cells make their own antibodies against the disease, immunity is permanent • Passive immunity – 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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