Viruses What do these diseases have in common

Viruses

What do these diseases have in common? Mumps http: //www. kcom. edu/faculty/chamberlain/Website/lectures/lectur e/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/Prof essionals/Diseases/Polio. jpg

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

Structure of a virus Complete the diagram! DNA Protein capsid (or RNA) Tube http: //mrsec. wisc. edu/Edetc/technologist/thumbnails/Matt/Virus_diagram. jpg Tail Fiber http: //www. humanillnesses. com/images /hdc_0001_0_img 0008. jpg http: //www. aidsactioncoalition. org/images/hiv_virus. gif

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/sf 11 x 1 virus. jpg

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

Archaea and Bacteria

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!

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/c 27 x 3 pr oc_shapes. jpg

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

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.

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.

Vaccines § 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 B 1%5 D. JPG http: //www. biojobblog. com/vaccination(5). jpg

§ 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