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Viruses

Viruses. -Segments of RNA or DNA contained In a protein coat. Viruses are not living!!!. 1) Viruses are not made of cells 2) Viruses do not grow 3) Viruses can’t reproduce on their own. 2 Main Shapes of Viruses. 1) Helical Virus - Rodlike

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Viruses

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  1. Viruses -Segments of RNA or DNA contained In a protein coat

  2. Viruses are not living!!! • 1) Viruses are not made of cells • 2) Viruses do not grow • 3) Viruses can’t reproduce on their own

  3. 2 Main Shapes of Viruses 1) Helical Virus - Rodlike - Capsid proteins winding around core in a spiral

  4. 2 Main Shapes of Viruses 2) Polyhedral Virus -Many sides, roughly spherical -Most efficient at holding viral genes

  5. Bacteriophages • Viruses that infect bacteria • Structure is polyhedron capsid w/ helical tail

  6. How can a Virus Reproduce? • Infect a living cell • Living cell reads viral nucleic acids and produces more viruses • Bacteriophages go through the lytic or lysogenic cycle

  7. Lytic Cycle • Viral genes are injected into the host cell • Host cell replicates viral genes and make viral proteins (capsids) • Genes and viruses are put together • Process repeats until cell bursts

  8. Lytic Cycle • http://student.ccbcmd.edu/courses/bio141/lecguide/unit3/viruses/lytlc.html#rellyt

  9. Lysogenic Cycle • Viral gene is inserted into host chromosome (provirus) • When cell divides, provirus divides • Change in environment can begin lytic cycle

  10. Lysogenic Cycle • http://student.ccbcmd.edu/courses/bio141/lecguide/unit3/viruses/repmatly.html • http://www.youtube.com/watch?v=_J9-xKitsd0

  11. Emerging Viruses • Viruses that evolve in geographically isolated areas and are pathogenic to humans • Hanta Virus • Ebola Virus

  12. Hantavirus Pulmonary Syndrome • May 1993 • Acute respiratory symptoms • Breathing in air contaminated w/ the virus • Urine and feces

  13. Ebola Virus • 1976 • Severe, often fatal disease • Found in humans and non-human primates • Gabon, Sudan, the Ivory Coast, Uganda, and the Republic of the Congo. • http://www.cdc.gov/ncidod/dvrd/spb/mnpages/dispages/ebola/ebolatable.htm

  14. Why do we encounter emerging viruses? • http://ffh.films.com/id/9505/The_Emerging_Viruses.html

  15. Prions • Proteins and no nucleic acids • Cause disease by influencing how proteins fold • Misfolding spreads like a chain reaction • Mad Cow Disease • Creutzfeldt-Jakob disease

  16. Bacteria • http://video.google.com/videosearch?hl=en&q=bacteria&safe=vss&um=1&ie=UTF-8&sa=N&tab=wv#

  17. What are Bacteria? • Single celled, prokaryotic organisms • 1/10 the size of most eukaryotic cells -http://www.cellsalive.com/howbig.htm • Have a single circular piece of DNA • Reproduce by Binary Fission • Anaerobic and aerobic processes (Euk are mostly aerobic) • Flagella is simple • Some have pili

  18. Pilihttp://microbiologybytes.com/video/photosynthesis.html • Along with gel-like capsule, pili help bacteria adhere to surfaces • Enable Conjugation-two organisms exchange genetic material

  19. Cell Walls • Most Bacteria have 2 types of cell walls -Gram-negative -Gram-positive The 2 types differ in susceptability to anti- biotics -Chemicals that interfere with life processes in bacteria

  20. Three Basic Shapes • Bacillus (buh SIHL uhs) -Rod shaped • Coccus (KAHK us) -Round shaped • Spirillium (spy RIHL uhm) -Spiral shaped

  21. Baccilus Northwestern Link

  22. Coccus http://biology.northwestcollege.edu/biology/b1010lab/bacillus1.jpg

  23. Spirillium http://biology.northwestcollege.edu/biology/b1010lab/bacillus1.jpg

  24. Which is Which???

  25. Aggregating Bacteria • Strepto- form filaments • Staphylo- form clusters

  26. How Bacteria Cause Harm • Metabolize their host • Secrete chemical compounds

  27. Metabolizing their host • Acne • Propionibacterium acnes, grow in the oil glands of skin • Metabolize certain kind of oil produced by glands • Oil glands increase oil production during puberty • Food increases so bacteria population increases • http://www.nlm.nih.gov/medlineplus/tutorials/acne/htm/_no_50_no_0.htm • Myths

  28. Metabolize their Host • Mycobacterium tuberculosis • Once one of most common causes of death (1.6 million in 2005) • Incidence rates have stabalized • Contracted from inhaling droplets of moisture containing bacterium • Cough up sputum (saliva mixed w/ mucus or puss) and blood, chest pain, fever, fatigue, weight loss • Over one third of world population is infected (5-10% will become sick)

  29. Secrete Chemical Toxins • Staphylococcus aureus • Causes most common food poisoning • Nausea, vomiting, diarrhea

  30. Secrete Chemical Toxins • Clostridium botulinum • Causes botulism • From improperly heated canned food • Double vision and paralysis • May die because can’t breath • 1g would is potent enough to kill 1 million people

  31. Relevance of Bacteria • Living with you • Food • Antibiotics

  32. Living with You • Streptococcus pneumoniae - present in upper respiratory tract of half the population • E. coli - Present in small intestine. Aids in digestion • Streptococcus aureus - causes most common staph infections. • Found in Nose and on skin

  33. Food • Fermented food • Pickles, buttermilk, cheese, saurkraut, olives, vinegar, and sourdough bread

  34. Antibiotics • Can be naturally produced by fungus or imitated chemically • Penicillium was first used antibiotic • Either stop bacteria from multiplying (bacteriostatic) or interferes with formation of cell wall or cell contents (bactericidal) • Over 100 types and most often perscribed medicine

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