1. Chapter 17 Viruses & prokaryotes

2. 17-1 Viruses  What is a virus?  How do viral life cycles differ?  What is the relationship between viruses and their hosts?

3. What is a virus?  A virus is a noncellular particle made up of genetic material and protein that can invade living cells  First discovered in 1935 by an American scientist named Wendell Stanley  It was called the tobacco mosaic virus or TMV

4. TMV on tobacco plant http://healthyhomegardening.com/Disease.php?pid=15

5. http://concerncrisis.blogspot.com/2008/03/tobacco-mosaic-virus-tmv.html

6. Structure of a virus  Composed of a core of DNA or RNA surrounded by a protein coat called a capsid  Capsid protects the genetic material  The core contains several genes to several hundred genes

7. http://micro.magnet.fsu.edu/cells/virus.html

8.  More complex structures are in viruses called bacteriophages – viruses that invade bacteria  Has a head region (capsid), a nucleic acid core, and a tail  Some have tail fibers that allow them to attach to the bacteria

9. http://micro.magnet.fsu.edu/cells/virus.html

10.  Viruses are rod-shaped, tadpole- shaped, helical and cubelike shaped  Vary in size from 20 to 400 nanometers  A nanometer is one billionth of a meter

11. http://learnsomescience.com/microbiology/viruses-viroids-and-prions/

12. Specificity of a virus  Specific viruses infect specific organisms  Plant virus cannot infect an animal  Only mammal viruses that do not infect other animals and vise versa  Viruses for every type of organism

13. http://www.wellesley.edu/Chemistry/Chem101/dna-viruses/viruses.html

14. Life cycle of a Lytic Virus  In order to reproduce, viruses must invade, or infect, a living host cell  They also invade in different ways…  One way is done by lytic viruses where when they invade the cell bursts or lyses

15. Life cycle of a lytic virus http://dvm5.blogspot.com/2010/11/classification-of-viruses.html

16. Infection  A virus is activated by contact with the right host cell (chance)  It then injects its DNA into the cell

17. Life cycle of a lytic virus http://dvm5.blogspot.com/2010/11/classification-of-viruses.html

18. Growth  The RNA polymerase of the host cell creates messenger RNA of the virus DNA  This mRNA then takes over the host cell  Some proteins turn off the creation of molecules for the cell

19. Life cycle of a lytic virus http://dvm5.blogspot.com/2010/11/classification-of-viruses.html

20. Replication  It then uses the host cell to make thousands of copies of its own protein coat and DNA  The host cell is then filled with viral DNA molecules  These three steps can happen in 25 minutes

21. Life cycle of a lytic virus http://dvm5.blogspot.com/2010/11/classification-of-viruses.html

22.  The infected cell then lyses (bursts) and releases hundreds of virus particles  These particles than infect other cells  The host cell is lysed and destroyed so this process is called lytic infection

23. http://en.wikipedia.org/wiki/Lytic_cycle

24. Lysogenic Infection  Lysogenic infection-the virus does not reproduce and lyse its host cell  The DNA of the virus enters the cell and is inserted into the DNA of the host cell  The viral DNA is then known as a prophage

25. Prophage activity  Blocks entry of other viruses and may even add useful DNA to the host cell’s DNA  Eventually it will remove itself from the DNA and create new virus particles

26. http://en.wikipedia.org/wiki/Lytic_cycle

27. Retroviruses  Retroviruses contain RNA as their genetic information  When they enter the cell they produce a DNA copy  This then enters into the host cells DNA

28. http://ucdbiotech.wordpress.com/2009/10/13/be-on-the-alert-the-first-ever-gammaretrovirus-capable-of-infecting-human-hosts-has-been-identified /

29. Viruses and Living Cells  Viruses must infect living cells to carry out their functions  Viruses are parasites-an organism that depends entirely upon another living organism for its existence in such a way that it harms that organism

30. http://westernrifleshooters.blogspot.com/2011/02/interview-with-stanley-kurtz.html

31. Are viruses alive?  Viruses are not made of cells  They can grow, reproduce, regulate gene expression, an evolve  It is up for debate

32. Virus video Virus video

33. 17-2 Prokaryotic Cells Bacteria Intro video http://hyperphysics.phy-astr.gsu.edu/hbase/biology/imgbio/cellprokaryote6.gif

34. Prokaryotes  Cells that do not have a nucleus http://en.wikipedia.org/wiki/Prokaryote

35. Eubacteria http://calexa.weebly.com/eubacteria.html

36. Cyanobacteria http://user.uni-frankfurt.de/~schauder/cyanos/cyanos.html

37. Archaeabacteria  Methanogens – archaeabacteria that produces methane gas http://en.wikipedia.org/wiki/Archaea

38. Prochlorobacteria http://jk169.k12.sd.us/proteobacteria.htm

39. Bacteria (E. Coli)  One-celled prokaryotes http://en.wikipedia.org/wiki/Bacteria

40. They do not contain the complex range of membrane enclosed organelles that are found in most eukaryotic cells http://www.weblife.org/humanure/images/fig3-1.jpg

41. Eubacteria Structure –generally surrounded by a cell wall made of carbohydrates –there is a cell membrane which surrounds the cytoplasm –long whip like flagella protrude from the membrane through the cell wall

42. Eubacteria http://upload.wikimedia.org/wikipedia/commons/thumb/5/5a/Average_prokaryote_cell-_en.svg/494px-Average_prokaryote_cell-_en.svg.png

43. They use photosynthesis to get energy http://www.biologie.uni-hamburg.de/b-online/library/webb/BOT311/Cyanobacteria/CyanoHyellaStella300Crop.jpg

44. Fresh and saltwater, land, hot water, arctic, grow on snow http://lyxia.us/wp-content/uploads/2012/08/cyanobacteria-1.jpg

45. Methanogens are archaebactria that produce methane gas http://www.daviddarling.info/images/methanogens_large.jpg

46. prochlorobacteria more related to chloroplasts http://jk169.k12.sd.us/images/Escherichia_coli1355024.300a[1].jpg

47. Bacteria Identification –cell shape –Cell Wall –Bacterial Movement –How the obtain energy

48. Bacterial shape https://benchprep.com/blog/ap-biology-diversity-of-organisms-kingdoms-part-i/

49. Gram Staining  There are two types of dye, The bacterial cells with only one thick layer of carbohydrate and protein molecules outside the cell membrane took up the crystal violet. The bacterial cells that have lipid and carbohydrate molecules appear red under the microscope and are gram negative

50. Gram Staining http://en.wikipedia.org/wiki/Gram_staining

51. Bacterial movement –propelled by flagella –spiral forward –glide slowly http://upload.wikimedia.org/wikipedia/commons/thumb/1/15/Flagellum_base_diagram_en.svg/629px-Flagellum_base_diagram_en.svg.png

52.  Phototrophic autotrophs-prokaryotes that trap the energy of sunlight  Chemotrophic autotrophs-prokaryotes that live in harsh environments and obtain E from inorganic molecules  Chemotrophic heterotrophs-bacteria that obtain energy by taking in organic molecules and then breaking them down and absorbing them  Phototrophic heterotrophs- use sunlight for Energy but also need organic compounds for nutrients

53. Obligate aerobes (tuberculosis)  Require oxygen http://www.news-medical.net/health/What-is-Tuberculosis.aspx

54. Obligate anaerobes (Clostridium botulinum)  Bacteria that do not require oxygen http://www.agefotostock.com/en/Stock-Images/Rights-Managed/BSI-0217005

55. Toxins  Poisons that can cause botulism which is a rare form of food poisoning (paralysis) http://www.sciencedaily.com/releases/2008/06/080616115718.htm

56. Facultative anaerobes (Gardnerella)  Bacteria that can survive with or without oxygen http://www.redorbit.com/education/reference_library/health_1/bacteria/2584148/gardnerella/

57. Binary Fission  Bacterial cell replicates its DNA and divides in half (asexual reproduction) http://biology.about.com/od/cellanatomy/ss/prokaryotes_2.htm

58. Conjugation  Genetic information from one bacteria is transferred to the other (sexual reproduction) http://partsregistry.org/Conjugation

59. Endospore  Spore formed when a bacterium produces a thick internal wall that encloses its DNA and portion of its cytoplasm (Not reproduction) http://en.wikipedia.org/wiki/File:Electron_micrograph_of_endospore_of_the_bacterium_Carboxydothermus_hydrogenoformans.png

60. Bacteria food production http://www.jgi.doe.gov/News/news_10_17_06.html

61. Symbiotic relationship (E. Coli)  Both organisms benefit http://blog.search-mojo.com/2010/10/26/googles-symbiotic-relationship-with-seos-yeah-right/

62. They are able to break down cellulose due to the bacteria that make enzymes that allow animals to digest cellulose http://www.quia.com/files/quia/users/lmcgee/biochemistry/cellulose-cows.gif

63. They recycle and decompose, or break down dead material

64. Saprophyte bacteria  Bacteria that digest organic matter and break it down to simpler substances http://www.apsnet.org/edcenter/intropp/lessons/prokaryotes/Pages/BacterialBlotch.aspx

65. Bacteria sewage decomposition http://healthnews-younis.blogspot.com/2010/12/turning-up-heat-on-antibiotic-resistant.html

66. Nitrogen Fixation (Rhizobium) http://textbookofbacteriology.net/Impact_2.html

67. 17-3 Diseases Caused by Viruses and Prokaryotes  Only a small number of viruses and prokaryotes are capable of disease in humans  Pathogens-disease producing agents  Its basically a battle for nutrients between the host cell and the microorganism

68. Pathogens http://www.beltina.org/health-dictionary/pathogen-definition-what-is.html

69. Viruses and Disease  Viruses are the cause of such human diseases as small pox, polio, measles, AIDS, mumps, influenza, yellow fever, rabies, and the common cold  Caused from the virus life cycle  The only successful protection against them is preventing their infection

70.  The immune system must be stimulated to prevent the infection  They stimulate them with vaccines which inject a weakened or killed disease causing virus  Once a viral infection starts, there is little science can do to stop the disease  They mainly treat the symptoms

71. Vaccines http://www.fbresearch.org/TwoColumnWireframe.aspx?pageid=123

72. Interferons  These are small proteins that are produced by the body’s cells when the cells are infected by viruses  Seem to make it more difficult for the virus to spread  Could be used to fight viruses

73. Interferons http://www.odec.ca/projects/2007/sank7b2/page7.html

74. Cancer  Some viruses cause cancer in animals called oncogenic viruses  Virus adds certain genes to the cell to make it a cancer cell  Not very common  The Rous Sarcoma Virus (RSV) is an example in chickens

75. Rous Sarcoma Virus http://dict.youdao.com/w/rous_sarcoma_virus/#q%3Drous_sarcoma_virus

76. Bacteria and Disease  Only a few bacteria produce diseases  Some of the diseases caused by pathogenic bacteria include diphtheria, tuberculosis, typhoid fever, tetanus, leprosy, syphilis, cholera, and bubonic plague

77. Bacterial Diseases http://en.wikipedia.org/wiki/Bacteria

78.  Cause disease in two general ways: –May damage the cells and tissues of infected organisms directly by breaking down its living cells to use for food –May release toxins that travel throughout the body, interfering with the host  Many diseases can be prevented by stimulating the immune system as well

79.  There are also many other ways to fight against bacteria once infected  One is drugs and natural compounds, known as antibiotics, that attack and destroy bacteria  This has increased life expectancy over the last two centuries

80. Antibiotics http://www.nlm.nih.gov/medlineplus/antibiotics.html

81. Controlling Bacteria: Sterilization  Sterilization destroys living bacteria with great heat or chemicals  Bacteria cannot survive high temps so most can be killed boiling water  Disinfectants are another good way to sterilize many places

82. Sterilization http://preparednesspro.wordpress.com/2009/08/11/myths-and-facts-of- water-storage/water-storage-myths-boiling-water/ http://ykalaska.wordpress.com/2006/05/03/disinfectants-for-camp-field-and-household/

83. Food Processing  Bacteria are everywhere including in our food (if we don’t eat it they will which spoils it)  Refrigeration causes bacteria to not grow as fast  Many foods are sterilized by boiling, frying, or steaming (kills bacteria

84. Food Spoilage http://chefsblade.monster.com/training/articles/221-a-guide-to-food-pathogens

85.  Food that is properly canned will last pretty much indefinitely  Chemical treatments such as salt, vinegar, or sugar also preserve the food  Examples: salted meat, pickled vegetables, and jam

86. Canning http://www.foodinjars.com/2011/08/canning-101-tomato-float-sauce-separation-and-loss-of-liquid/