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Virus

Virus. Latin for “poison”. A virus is a particle that can only be seen with an electron microscope. Viruses are not cells and are not made-up of cells. They don’t… Contain a nucleus or cytoplasm Eat Grow Carry on respiration Or perform other biological functions.

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Virus

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  1. Virus Latin for “poison” A virus is a particle that can only be seen with an electron microscope.

  2. Viruses are not cells and are not made-up of cells. They don’t… • Contain a nucleus or cytoplasm • Eat • Grow • Carry on respiration • Or perform other biological functions

  3. A virus is surrounded by a capsid (protein coat) which determines the shape of the virus. The capsid contains nucleic acids (either DNA or RNA). Tail fibers for attachment to host cell.

  4. Viruses are classified by: • type of host cell • presence of DNA or RNA (retroviruses) • shape: Binal Polyhedral Filo

  5. VIRAL REPLICATION Viruses replicate in one of two ways: • Lytic • Lysogenic

  6. LYTIC CYCLE Virus attaches to host cell. Virus injects its DNA Cell lyses (breaks apart) and new viruses are released Virus DNA commands host cell to make new viral parts New viral parts assembled

  7. LYSOGENICCYCLE http://www.howstuffworks.com/virus-human2.htm

  8. LYSOGENIC CYCLE • Does not begin immediately • Viral DNA (called a prophage) attaches to the host cell’s chromosomes – lies dormant. • Environmental stimulus sends viral DNA into lytic cycle.

  9. VIRAL DISEASES

  10. Most viruses have NO cure (Influenza, & HIV), but some viruses like Small- pox have vaccines. Vaccines contain a weakened or killed virus that provides immunity to the disease.

  11. BACTERIA • Prokaryotic = no nucleus • Unicellular = one cell • Mostly heterotrophic = cannot make own food

  12. Two Kingdoms of Bacteria: (Based on differences in structure of DNA, cell wall and cell membrane) Eubacteria and Archaebacteria

  13. Archaebacteria • “Archae” Means Ancient • Live In Extreme Conditions • Such As Hot Springs • Highly Salty Water

  14. Eubacteria • “Eu” (True) • Live almost everywhere • Fresh and salt water • Land • In Humans E.coli

  15. Identification(based on shapes, cell walls,movement and by the way they obtain energy) • Shapes: • Bacilli = rods • Cocci = round • Spirilla = spiral

  16. BACILLI (RODS)

  17. COCCI (ROUND)

  18. SPIRILLI (SPIRAL)

  19. A • Prefixes: • Diplo = 2 • Strepto = chain • Staphylo = clumps B C

  20. More Identification • Gram Staining is used to identify bacteria with extra membranes. These bacteria are more resistant to damage. • Gram + stain purple • Gram – (extra membrane) stain red

  21. Even More Identification MOVEMENT: • Flagella • Glide on slime • Wiggle • None

  22. Reproduction • Asexual: Binary fission

  23. Sexual: Conjugation • Endospores: protect genetic material until environment is favorable for reproduction.

  24. Roles • Symbiotic relationship – E.coli in the intestines aid in digestion in exchange for food and a warm home.

  25. Recycle Chemicals • Decomposers • Oil-eating bacteria • Break-down raw sewage • Nitrogen-fixation: change nitrogen to a form that producers can use to make protein.

  26. buttermilk Many fermented foods are produced with the help of bacteria. • Cheese • Buttermilk • Sour cream • Vinegar • Pickles • Sauerkraut • Sourdough bread

  27. Pathogen:Disease-causing Agent • Bacteria cause disease in 2 ways: • Damage cells • Release toxins (poisons) Anthrax Acne

  28. BACTERIAL DISEASES

  29. Control • Antibiotics: medicines that stop bacterial growth • Sterilization: heat or disinfectant • Cook food all the way Prevention=vaccines

  30. Immune System What is the main function? This system fights infectious diseases.

  31. Also, identify “nonself cells” (don’t belong in your body) from “self cells” (belong in your body).

  32. GERM THEORY There is a relationship between microorganisms and diseases. Pasteur Koch Lister

  33. How are diseases transmitted? direct contact animal bites food indirect contact

  34. What is your first line of defense? skin • Keep out pathogens • Nonspecific (does not discriminate) sweat tears mucus

  35. Your Second Line of Defense • The Inflammatory Response • Reaction to tissue damage • Nonspecific • Redness and swelling

  36. THIRD LINE OF DEFENSE • The Immune Response • Specific • Triggered by antigens • Two parts: • Humoral Immunity(B-cells) • Cell-mediated Immunity(T-cells)

  37. HUMORAL IMMUNITY • Fights pathogens in body fluids. • B-cells produce antibodies that mark antigens for destruction.

  38. CELL-MEDIATED IMMUNITY • T-cellsdirectly attack harmful cells. • Harmful cells include cancerous, infected or transplanted cells.

  39. There are different kinds of T-cells: Killer Helper Suppressor

  40. Killer T-cells kill harmful cells.

  41. Helper T-cellscall in more Killer T-cells and tell the B-cellswhen to make antibodies.

  42. The Suppressor T-cellstell the B-cells to stop making antibodies.

  43. M ACQUIRED IMMUNITY • Memory T and B cells remember previous antigens. • If the same antigen enters the body again, the memory T and B cells trigger a secondary response.

  44. http://www.harbinson.fslife.co.uk/e-coli.jpg http://www.okstate.edu/OSU_Ag/fapc/fsw/bacteria.jpg http://www.plantsci.cam.ac.uk/plantsci/teaching/1aqb/images/image4.gif http://images.google.com/imgres?imgurl=www.cs.unm.edu/~williams/cs257/ecoli/flagella.gif&imgrefurl

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