Microbiology Exam 2

  1. complete elimination of all lifeforms, including endospores
  2. elimination of all vegetative cells of pathogens
  3. what does disinfection NOT kill?
    non-pathogenic cells
  4. reduction of pathogens to a safe level
  5. how do safe levels vary in sanitization?
    from pathogen to pathogen
  6. disinfectants that are approved for use on the body
  7. specific way the method accomplishes killing or inhibition
    mechanism of action
  8. what are the three most common mechanisms of action?
    damage to proteins and dna, altering of membrane permeability, and slowing down metabolism
  9. what are some methods that work by damaging proteins and dna?
    wet heat, heavy metals, radiation, etc
  10. what methods work to alter membrane permeability?
    phenolics and quats
  11. phenolics and quats do what to a membrane?
    insert themselves into the membrane and form holes that ruin membrane integrity
  12. what are some methods that slow down metabolism?
    bacteriostatic - cold and dessication
  13. methods of controlling bacteria can be one of what two things?
    physical or chemical
  14. how do physical methods of control work?
    altering the physical environment
  15. what are some physical methods of control?
    heat, cold, radiation, desiccation, osmotic pressure, filtration, soaps/detergents
  16. how do chemical control methods work?
    employ some kind of chemical attack
  17. what are some chemical methods of control?
    phenolics, halogens, alcohols, heavy metals, aldehydes, quats, peroxides
  18. mechanism of action of moist heat
    denatures proteins
  19. what is moist heat?
    hot water or steam
  20. what is an example of moist heat?
    boiling, autoclaving, pasteurization
  21. endospores survive boiling, especially under what amount of time?
    10 minutes
  22. how do autoclaves work?
    use steam under pressure to denature proteins
  23. what is the time/temp combo most used in autoclaves?
    121 celsius for 15 minutes (15 psi)
  24. what is the target organism for the pasteurization of milk?
    coxiella burnetii
  25. what are some other autoclaves?
    home and commercial canners
  26. what are commercial canners called? what is their process called?
    retorts; commercial sterilization
  27. what is the target organism of commercial canning?
    endospores of clostridium botulinum
  28. home canners (pressure cookers) should be operated at what time/temp combo?
    121 celsius for 15 min (15 psi)
  29. what is the most common cause of botulism?
    inadequately processed hoe canned foods
  30. mechanism of action of dry heat
    kills by burning
  31. what is dry eat?
    fire or hot air
  32. what is an example of dry heat?
  33. dry heat is less/more effective than moist heat at the same temperature?
  34. what is the most common time/temp combo used to sterilize with hot air?
    160 celsius for 120 min
  35. what is dry heat used on?
    glass and metal
  36. some hospitals have their own what?
    incinerator for biological wastes
  37. what happens to the carcasses of cattle effected with anthrax?
    incinerated to make sure endospores are destroyed
  38. what causes anthrax?
    bacillus anthracis
  39. what is a method of dry heat used in lab?
    flaming loops
  40. mechanism of action of cold
    slows metabolism
  41. what is an example of cold?
    freezing, refrigeration
  42. cold temperatures are bacteriostatic or bacteriocidal?
  43. what is the growth of mesophiles inhibited by?
    refrigeration temperatures
  44. what mesophile grows well at refrigeration temperatures?
    listeria monocytogenes
  45. mesophiles include most what?
  46. what grows at refrigeration temperatures? what are they responsible for?
    psychrotrophs, refrigerated food spoilage
  47. what is the most common spoilers of raw meats?
    psuedomonas fragi
  48. mechanism of action of radiation
    damages dna
  49. what is an example of radiation?
    ionizing and non-ionizing
  50. what radiation is ionizing?
    gamma rays, x rays, electron beams
  51. what radiation is non-ionizing?
  52. ionizing radiation is energetic enough to do what?
    knock electrons off of atoms
  53. what rays are used for sterilizing packaging materials?
    gamma rays and xrays
  54. what is the most commonly used source of gamma rays?
  55. UV radiation is useful for what?
    surface air treatment (hospitals)
  56. what is the most effect wavelength of uv light?
  57. what is 260nm the bst wavelength?
    dna absorbs uv rays best at this wavelength
  58. what does UV cause?
    thymine dimers
  59. what does the formation of thymine dimers do to dna?
    changes shape of dna molecule, which causes enzymes that make dna copies to malfunction
  60. hospitals may have what used to disinfect?
    UV lights to disinfect the air
  61. the biological hood contains what?
    UV light and HEPA filter
  62. mechanism of action of dessication
    slows metabolism
  63. what is an example of dessication?
    dehydrating or drying foods
  64. dessication is bacteriostatic or bacteriocidal?
  65. how does desiccation work?
    all organisms require water, when moisture becomes too low enzymes no longer function and metabolism stops
  66. foods with what concentration of water inhibit microbial growth?
    less than 20%
  67. foods that inhibit all microbial growth are resistant to what?
  68. fungi tolerate low water levels better than what?
  69. molds may grow on what foods? why?
    cheese and bread, they grow in dry areas better than bacteria
  70. mechanism of action of osmotic pressure
    draw water out of cells and cause plasmolysis
  71. what is an example of osmotic pressure?
    high levels of sugar/salt in foods like jellie, james, honey, syrup, salty meat
  72. salted foods may be vulnerable to what pathogen?
    staphylococcus aureus
  73. staphylococcus aureus grows in salt concentrations of what?
    more than 7%
  74. mechanism of action of filtration
    removes microbes
  75. what is an example of filtration?
    operating rooms, biological safety hoods, membrane filters
  76. HEPA filter
    high-efficiency particulate air filters
  77. what are HEPA filters used for?
    to filter air
  78. to be a HEPA filter you must catch a minumum of which particles?
    99.97% of 0.3 micrometers (most bacteria are >1 micrometer)
  79. mechanism of action of soaps/detergents
    decrease surface tension
  80. what does the decrease of surface tension cause?
    microbes are allowed to be lifted up and carried off
  81. soaps and detergents have little or no what?
    germicidal action
  82. rather than kill microbes what do soaps/detergents do?
    make it easir to rub and rinse away microbes on surfaces
  83. terms like "sanitizer", "disinfectant", "antimicrobial" cannot be put on labels until when?
    approved by meeting government regulations
  84. antimicrobial products are regulated by who when products are meant to be used on environmental surfaces?
  85. antimicrobial products are regulated by who when products are more for use on the body or could enter the body?
  86. EPA
    environmental protection agency
  87. FDA
    food and drug administration
  88. EPA calls their products what? FDA calls their products what?
    pesticides, drugs
  89. what microorganisms are most resistant to chemicals? why?
    endospores and mycobacteria; waxy mycolic acid coat
  90. what organisms are generally more resistant than bacteria to chemicals?
  91. bacteria are generally more resistant than who to chemicals?
  92. list major groups of microorganisms from most resistant to least resistant
    • endospores
    • mycobactera
    • cysts of protozoa
    • vegetative protozoa
    • gram-negative bacteria
    • fungi (including fungal spores)
    • non-enveloped viruses
    • gram-positive bacteria
    • enveloped viruses
  93. some viruses are surrounded by a membrane called what?
  94. mechanism of action of phenolics
    disrupt cell membranes
  95. what is an example of a phenolic?
    thymol, triclosan
  96. phenolics are effective against what?
  97. thymol is an active ingredient in what?
  98. triclosan is the active ingredient in what?
    antibacterial handsoaps and detergents
  99. antibacterial liquid handsoaps in the lab contain what?
  100. mechanism of action of halogens
    inhibit proteins
  101. what is an example of a halogen?
    fluoride, chlorine, hypochlorite (HOCl), iodine, iodophors
  102. fluoride is in what?
    toothpaste (~1000ppm)
  103. chlorine is used for what?
    treat drinking water (~1ppm)
  104. what is hypochlorite an active ingredient in?
    bleach (5% hypochlorite)
  105. what is iodine useful for?
    prepping skin before an injection
  106. what are iodophors?
    iodine combined with detergents
  107. what are iodophors useful for?
    prepping areas before surgery (disinfect and have cleaning action)
  108. mechanism of action of alcohol
    inhibit proteins, dissolve lipids
  109. what is an example of an alcohol?
  110. isoproponal is a common what?
    household disinfectant (rubbing alcohol)
  111. ethanol is often used for what?
    injection prep
  112. what do we use ethanol in lab for?
    soaking metal spatulas
  113. what happens after spatulas are soaked in ethanol in lab?
    passed through flame to burn off alcohol
  114. what is the most effective concentration of ethanol or isoproponal?
    70% (some water is required in order to denature proteins)
  115. mechanism of action of heavy metals
    inhibit proteins
  116. what is an example of a heavy metal
    silver, copper
  117. what was traditionally place on eyes of newborns?
    drops of 1% silver nitrate
  118. what was silver nitrate used to prevent? how would that be passed to the child?
    neisseria gonorrhoeae infections, passed during birth
  119. what antibiotic is used today to place on eyes of newborns?
  120. why is erythromycin used today in newborns?
    the rise in chlamydia trachomatis eye infections, silver nitrate couldn't effectively kill it
  121. what is copper sulfate used for?
    treat swimming pool water (prevent algal growth) and grapes (prevent fungal growth)
  122. mechanism of action for aldehydes
    inhibit proteins
  123. what is an example of an aldehyde?
  124. why is aldehyde a potential sterilant?
    effect even against endospores
  125. aldehydes are also potential what?
  126. what is probably the most effective groups of disinfectants? why aren't they used often?
    aldehydes, suspected carcinogens
  127. what have solutions of formaldehyde traditionally been used for?
    to embalm bodies or preserve biological specimens
  128. embalming solutions contain what percent of formaldehyde?
  129. mechanism of action of quats
    disrupt cell membranes
  130. what an example of a quat
    benzalkonium chloride
  131. what is benzalkonium chloride listed as on labels?
    alkyl dimethy benzyl ammonium chloride
  132. quats are toxic/nontoxic?
    non toxic
  133. quats can be used in sensitive areas such as what?
    eyewash solutions
  134. quats are active ingredients in what?
    lysol, fantastik, household sanitizers
  135. quats are the active ingredient in what in lab?
  136. mechanism of action of peroxides
    cause various oxidation reactions
  137. what is an example of a peroxide?
    hydrogen peroxide (h2o2)
  138. what peroxide is a common household disinfectant?
    hydrogen peroxide
  139. what is a common acne topical medication?
    benzoyl peroxide
  140. describe bacterial chromosomes and describe eukaryotic chromosomes
    singular, circular; multipl, linear
  141. E. coli has how many basepairs? how many genes? is this common for bacteria?
    4.6 million; 4,300; yes
  142. human dna contains how many base pairs? how many genes?
    3.4 billion; 20,000
  143. bacteria also contain what in their dna?
  144. plasmids have genes for what?
    toxins or resistances to antibiotics/disinfectants
  145. what are some processes involving dna?
    replication, transcription, translation, genetic recombination
  146. dna replication
    copy of chromosome is made
  147. transcription
    rna is made using information in dna
  148. translation
    proteins are made using information in rna
  149. genetic recombination
    segments of dna are transferred from one chromosome to another
  150. where does dna replication occur?
    cytoplasm, specifically the nucleoid
  151. where does dna replication occur in eukaryotes?
  152. bacterial chromosomes have a single origin of replication, which is where?
    a specific sequence of nucleotides recognized by the replication enzymes
  153. eukaryotic chromosomes are larger than bacterial chromosomes so they have how many origins of replication?
  154. what happens once replication is finished?
    new chromosome copies remain attached to proteins in cell membrane, this allows copies to seperate during binary fission
  155. how does dna replicate in eukaryotes?
    spindle fibers move chromosomes around during mitosis
  156. major enzymes involved in dna replication
    dna helicase and dna polymerase
  157. what does dna helicase do?
    uncoils the dna helix and seperates the two strands
  158. what does dna polymerase do?
    lays down the new nucleotides and forms new strands of dna
  159. what are the short lengths produced on discontinuous dna strands are called what?
    okazaki fragments
  160. what is rna used to make?
  161. where does transcription occur?
  162. where does transcription occur in eukaryotes?
  163. what is the major enzyme responsible for bacterial transcription
    rna polymerase
  164. how does rna work to transcribe a gene?
    rna polymerase binds to the dna at the promoter, then seperates the two strands of dna and begins reading dna in one strand, it attaches rna nucleotides according to the nucleotide sequence in dna, and the rna molecule lengthens
  165. bacterial dna contains no what?
  166. what are introns?
    segments of rna that must be removed in order to produce the proper protein later during translation
  167. do eukaryotic rna contain introns?
  168. why are there no introns in bacterial rna?
    there is no time to remove introns
  169. how fast does rna work?
    translation usually begins before transcription ends (before rna is finished being made, ribosomes are already grabbing it and trying to make proteins using the information already there)
  170. where does transcription and translation occur in eukaryotes?
    nucleus, cytoplasm
  171. what are the major structures for bacterial translation?
  172. what are ribosomes made of?
    part protein and part RNA
  173. bacterial cells usually have how many ribosomes?
  174. ribosomes read information in rna how many nucleotides at a time?
  175. what are three sets of nucleotides called?
  176. what does a single codon indicate?
    a specific amino acid that will be added to the protein
  177. what specific codon does translation begin at?
    AUG or the start codon
  178. how are new amino acids delivered?
    by pieces of tRNA (transfer rna)
  179. ribosome continues reading codons and adding amino acids until when?
    it reaches one of the three stop codons, then the ribosome disnegages and the new protein is released
  180. what are the three types of rna that participate in translation?
    mRNA, tRNA, and rRNA
  181. mRNA
    contains the dna message and is the piece of RNA that the ribosome reads
  182. tRNA
    delivers the new amino acids to the ribosome
  183. rRNA (ribosomal)
    forms part of the ribosome (the rna part)
  184. why are bacteria able to adjust their metabolism more quickly than eukaryotic cells when the environment changes?
    bacterial transcription and translation aren't seperated by compartments
  185. what is a mutation?
    change in the nucleotide sequence of dna
  186. what are mutations caused by?
    spontaneous or mutagens
  187. spontaneous mutations are due to what?
    errors made by dna polymerase during replication
  188. what are mutagens?
    chemical or physical agents that cause dna polymerase to make mistakes
  189. how can mutations be repaired?
    dna polymerase has a self-checking ability and other enzymes (repair enzymes) patrol dna and detect unusual shapes
  190. what may mutagens be?
    radiation or chemicals
  191. what is a radiation mutagen?
    gamma rays, xrays, uv
  192. what is a chemical mutagen?
    aflatoxins, ethidium bromide, 5-bromouracil
  193. bacteriocidal uv lamps have what peak wavelength?
    260 nanometers
  194. how do chemical mutagens cause mutations?
    by changing the shape of the dna molecule
  195. what mold produces aflatoxins?
    aspergillus flavus
  196. what are the most carcinogenic naturally produced substances known?
  197. what are the most commonly contaminated foods by aflatoxins?
    peanuts, corn, and wheat
  198. what is ethidium bromide used for?
    stain gels after electrophoresis
  199. what is gel electrophoresis used for?
    to seperate dna fragments during dna fingerprinting
  200. where does the ethidium bromide bind during gel electrophoresis?
    to the dna and is used to located where the bands of dna occur
  201. where is 5-bromouracil commonly used? what for?
    in lab to cause mutations for experimental research
  202. where has 5-bromouracil been used out of labs?
    to treat cancer
  203. what enzymes are available to prevent/repair mutations?
    dna polymerase, photolyass, and endonucleases
  204. dna polymerase has what special function?
    a proof-reading function
  205. what is photolyase activated by? what does it do?
    light, break thymine diners and allow thymines to reattach to their original bases
  206. what does endonuclease do?
    cuts out affected nucleotides after thymine dimers and allows other enzymes to replace them
  207. what test is used to determine if a chemical is a mutagen?
    the ames test
  208. what does the ames test use?
    a his (histidine negative)
  209. what histodine negative does the ames test use?
    salmonella typhimurium
  210. how does the ames test work?
    • chemical being tested and rat liver extract are added to a tube containing salmonella typhimurium
    • time is permitted for mutations to occur and then the mix is plated on an agar without histidine
    • growth on agar means that mutations occured
  211. how would a mutagen survive on an agar?
    most cells die due to lack of histidine in the media, but mutagens will now be allowed to produce their own histidine and will survive
  212. why is rat liver extract used during the ames test?
    chemicals are not mutagenic in their original form but converted to mutagenic compounds by liver enzyme
  213. the ames tests does not just test one compound. why?
    enzymes in rat liver produces a variety of molecules when mixed with original chemical, so it is a test of the original compound and all of its variations
  214. what is genetic recombination?
    exchange of dna between two chromosomes
  215. what does bacterial recombination require? why?
    dna travel from cell to cell because bacterial chromosomes are singular
  216. how do movement of bacterial dna occur?
    transformation, conjugation, and transduction
  217. what is transformation?
    update of naked dna from the environment
  218. what is conjugation?
    direct transfer of dna from one cell to another
  219. what is transduction?
    transfer of dna from one bacterial cell to another by a bacteriophage (virus)
  220. how can transformation be improved in a lab?
    adding chemicals like mild detergents or passing an electric current through the solution (electroportation)
  221. what do the methods of lab transformation do to the membrane?
    ruin it, but not enough to kill it hopefully allowing fragments of dna to pass through
  222. how does conjugation occur?
    through direct contact
  223. how do gram-negative bacteria conjugate?
    using pilus to attach to the receiving cell and reel it into contact
  224. what species allow conjugation?
    genetically equipped with necessary structures
  225. what is passed during conjugation that would give off various resistances?
  226. why are plasmids so highly populated?
    copies are only given off during conjugation so both cells have this plasmid genes and they can pass them onto other cells
  227. what is one common conjugation plasmid?
    f factor in e. coli (f for fertility)
  228. what does the f. factor in e. coli produce?
    the ability to produce pilus
  229. plasmids that give cells the ability to undergo conjugation and pass resistances to other cells are called what?
    resistance factors
  230. what happens when a phage infects a bacterial cell?
    enzymes will cut up dna so when phage particles are being assembled pieces of bacterial dna may be packed in them
  231. what is genetic engineering?
    the process of inserting foreign genes into an organism (this is genetic recombination when it happens naturally)
  232. dna with foreign material inserted in it
    recombinant dna (rDNA)
  233. an organism with recombinant dna can be called what?
    recombinant, transgenic, or engineered organism
  234. what is the outline for how bacteria are engineered?
    • bacterial cells are processed and plasmids are collected
    • seperately, cells with the gene you want to transfer are process and dna is collected
    • plasmids and dna you want are cut open using enzymes and mixed together
    • peices of dna with the gene you want will be inserted into some plasmids
    • recombinant plasmids are inserted into new cells using transformation
  235. what are vectors? what is the vector during genetic engineering?
    transporters, plasmids
  236. what enzymes cut open dna and plasmids during genetic engineering?
    restriction enzymes
  237. what is the most commonly engineered bacterium?
    e. coli
  238. what is the most commonly engineered eukaryotic organism?
    saccharomyces cerevisiae (yeast)
  239. when are viruses used as vectors?
    used to engineer human cells for use in gene therapy
  240. what are restriction enzymes?
    bacterial enzymes that destroy phage dna
  241. where do restriction enzymes cut the dna?
    specific nucleotide sequences (produce sticky ends)
  242. what are sticky ends? why are they called this?
    short, single-stranded lengths; they tend to stick to complementary single strands
  243. why are restriction enzymes useful?
    pieces of dna cut with an enzyme can be inserted into the dna of another organism that's been cut with the same thing, they have the same sticky ends
  244. what is complementary dna (cDNA)?
    dna with the introns removed
  245. what do introns prevent?
    eukaryotic genes from being inserted into bacteria, because they cannot remove introns themself
  246. dna with the introns removed can be produced using what?
    transcriptase, enzyme produced by retroviruses
  247. what is a summary of how cDNA works?
    we use reverse transcriptase to produce cDNA and that allows us to engineer bacterial cells with eukaryotic genes
  248. what is gene therapy?
    genetic engineering of humans in order to treat disease
  249. what kind of virus is usually used in gene therapy?
    attenuated cirus
  250. why are viruses used during gene therapy on humans?
    they already have the ability to penetrate human cells and release dna
  251. what attenuated virus is usually used in gene therapy?
    adenoviruses (cause respiratory infections, like the common cold)
  252. what has gene therapy successfully been used to treat?
    SCID (severe combined immunodeficiency)
  253. what do individuals that have been treated for SCID using gene therapy have a high risk of developing?
  254. what is PCR (polymerase chain reaction)?
    process that makes multiple copies of a piece of dna (usually billions) within a couple of hours
  255. the process of pcr runs in cycles of what?
    heating and cooling of temps between 60-95 degrees Celsius, temperatures that would denature dna polymerase from mesophiles
  256. pcr requires a heat stable dna polymerase, usually from what thermophilic bacterium?
    thermus aquaticus
  257. the is the dna polymerase from t. aquaticus usually referred to as?
    taq polymerase
  258. what methods are commonly used to insert recombinant dna into cells?
    transformation, electroporation, microinjection, gene gun, viruses, and agrobacterium tumefaciens
  259. what is electroporation?
    a variation of transformation that uses an electric current to make the cell membrane leaky and allow dna to enter
  260. what is microinjection?
    dna can be injected directly into cells using an ultra-fine needle
  261. what is microinjection useful for? why isn't it useful for bacterial cells?
    animal cells and yeasts, it may be called microinjection but the needle is far too large for bacterial cells
  262. how do you use a gene gun?
    microscopic particles of gold are coated with dna and fire at cells
  263. the gene gun is used for what cells?
  264. how does agrobacterium tumefacians work?
    a plant pathogen that has the ability to inject dna into plant cells
  265. agrobacterium tumefaciens is a plant pathogen that causes what?
  266. the ability to inject the dna and cause disease are carried on what plasmid?
    ti-plasmid (tumor inducing)
  267. where has agrobacterium tumefaciens been used?
    used to engineer crops with various traits (ability to produce own pesticide), the crops produce protein crystals that harm digestive tracts of insects but are harmless to animals and human
  268. what pesticide can plants produce on their own after being injected with agrobacterium tumefaciens?
    bacillus thuringiensis
  269. what are the crops genetically engineered called?
    bt crops (bt corn, bt cotton, etc)
  270. what can dna fingerprinting be used for?
    to determine paternity, solve crime, trace outbreaks, and detect pathogens
  271. what process is used to make a dna fingerprint?
    cut up dna sample, copy it, seperate it, stain it, view it
  272. for fingerprinting what is used to copy dna?
    pcr makes multiple copies of fragments
  273. how does seperating dna work with dna fingerprinting?
    gel electrophoresis is used to seperate dna fragments according to length, electric current running through gel bath causes fragments to move through the gel, large fragments don't move far and small fragments do, this creates a fingerprint pattern
  274. how do you stain dna in dna fingerprinting?
    stained with ethidium bromide, dna gel is not visible so it must be stained to see, gel is soaked in a solution of ethidium bromide and the bromide wedges itself into the dna helix
  275. how do you view dna during dna fingerprinting?
    ethidium bromide is fluourescent, so when gel is exposed to uv light the band becomes visible
  276. how can bacteria be identified using fingerprinting?
    compare dna of a known species to the unknown species
  277. how is the taxanomic hierarchy same/different with prokaryotes than eukaryotes?
    it's the same except that prokaryotes are not assigned to kingdoms
  278. what are subspecies of bacteria called?
    stains or serotypes
  279. what is a strain of e. coli?
    e. coli 0157:H7
  280. what bacterial family includes e. coli, salmonella, proteus, and other gram-negative intestinal bacteria?
  281. what is the definitive guide to the identification and classification of bacteria?
    bergey's manual
  282. what three domains can all organisms on earth be divided into?
    archaea, bacteria, and eukarya
  283. bacteria domain is divided into more than how many phyla?
  284. what are three of the well-known phyla of bacteria?
    proteobacteria, firmicutes, and actinobacteria
  285. what bacteria are usually in the phylum proteobacteria?
  286. what are some well-known proteobacteria?
    genera: escherichia, proteus, psuedomonas, neisseria, and salmonella
  287. what does the phylum firmicutes include?
    low GC gram-postive bacteria
  288. what are the most well-known gram positive genera in firmicutes?
    clostridium, bacillus, lactobacillus, staphylococcus, and streptococcus
  289. what is GC content?
    the percent of base pairs in an organisms dna are that are guanine-cytosine (GC is below 50%)
  290. what does the phylum actinobacteria include?
    high GC gram-positive bacteria
  291. actinobacteria are often what?
  292. well known actinobacteria include what genera?
    streptomyces and mycobacterium
  293. more than how many species of fungi are known so far?
  294. fungi are prokaryotic/eukaryotic
  295. fungi are aerobic/anaerobic
    aerobic (molds/mushrooms), facultatively anaerobic (yeasts)
  296. what metabolic group do fungi belong to?
  297. how do fungi reproduce?
    using spores (molds/mushrooms) or by budding (yeasts)
  298. fungi are unicellular/multicellular
    molds and mushrooms are multicellular and yeasts are unicellular
  299. fungi contain what in their cell walls?
  300. fungi contain what in their cell membranes?
    sterols (ergosterol)
  301. most fungi are...?
    saprophytes (nutrients from dead and decaying material)
  302. what is an example of a yeast?
    saccharomyces cerevisiae (bread, beer, wine); candida albicans (yeast infections)
  303. molds and mushroom structures are made up of what to make what?
    multicellular hyphage to make a mycelium
  304. where do you find spores on mold mycelium?
    colored area in the center of a mold indicate spores
  305. what is an example of a mold?
    rhizopus stolonifer (black bread mold); penicillium (blue-green environmental mold)
  306. do molds and mushrooms produce sexually/asexually?
    both, either way they produce spores - if a spore lands in a suitable environment it germinates
  307. molds and mushrooms don't have sexes they have...?
    mating types - they produce asexually unti they meet an opposing mating type them produce sexually
  308. when does sexual reproduction occur in molds and mushrooms?
    opposite mating types fuse together (plasmogamy), their nuclei remaind seperate for a period of time, later when stimulted they nuclei fuse (karyogamy)
  309. where does most of the mushroom growth reside?
    below surface
  310. what is the part of the mushroom we see above ground? what is it's purpose?
    a solid mass of hyphae produced during sexual reproduction; disperse spores
  311. what produces penicillin?
    penicillium chrysogenum
  312. what can destructive fungi do?
    cause disease, spoilage, and destruction
  313. what are fungal infections called? what is an example?
    mycoses; yeast infectios caused by candida albicans
  314. what are fungal toxins called?
  315. what percent of fungal species are harmful to humans?
    less than 1%
  316. what percent of the worlds food crops are destroyed by fungi each year? what is an example?
    one-fourth; rhizopus stolonifer, penicillium
  317. how can molds cause destruction?
    mold growth in homes can require significant costs to replace damaged materials or remove toxins
  318. what is an example of a mold that can destroy a home?
    stachybotrys chartarum, black mold that grows on wet building materials
  319. what can stachybotrys chartarum cause?
    anything from headaches to organ damage
  320. are viruses alive?
    no, no metabolism, reproduction, or cells
  321. what size are viruses?
    smaller than bacteria, measured in nanometeres, require a microscope to see
  322. what do viruses contain?
    nucleic acid (rna or dna) and a protein coat (capsid)
  323. viruses whose nucleic acid is single stranded
  324. viruses whose nucleic acid is double stranded
  325. what is the envelope of a virus made of?
    cell membrane that the virus stole from the host cell when it escaped
  326. what can envelopes contain? what do they do?
    spikes, attach to host cell
  327. the cells a virus can infect is determined by what?
    specific receptors on the surface of cells
  328. a virus that infects a bacteria
  329. viruses must be grown how? why?
    by using a living host, they can't be grown in sterile media; they are obligate intracellular parasites
  330. how can bacteriophages be grown?
    in culture media with their bacterial host
  331. how can many animal viruses be grown?
    fertilized chicken eggs
  332. where are the viruses grown each year for use in influenze vaccines?
    chicken eggs
  333. virus multiplication can be divided into what five major events?
    attachment, penetration, biosynthesis, maturation, and release
  334. explain attachment of viruses
    physical attachment to host cell exterior, virus binds to a specific receptor which is usually a polysaccharide or a protein
  335. explain penetration of viruses
    movement of the virus from the exterior to the interior of the host cell
  336. how do non enveloped viruses enter cells?
    endocytosis, host cell membrane invaginates and surrounds the virus and brings it in the cell in a vesicle
  337. how do enveloped viruses enter the cell?
    endocytosis or fusion, the virus envelope melts into the host cell membrane
  338. how do plant viruses penetrate into plant cell walls?
    plant cell walls are tough so it only happens when plant cells are damaged (by insects or gardening tools)
  339. how is bacteriophage penetration accomplished?
    injecting the genetic material intot he cell wall while phage is outside the cell
  340. explain biosynthesis of viruses
    production of virion parts, production of new dna or rna and new capsid proteins
  341. explain maturation of viruses
    forms the whole mature virion
  342. explain the release of viruses
    escape of virions from interior of cell to exterior, these infect new cells
  343. how are enveloped viruses released?
    by budding (obtains its envelope from the cell membrane as it is exiting)
  344. how are non-enveloped viruses released?
    when host cell becomes so full that it ruptures
  345. when viral dna inserts itself into the host chromosome the viral dna is called?
    a provirus
  346. what are retroviruses?
    rna viruses
  347. what is an example of a retrovirus?
    HIV, causes AIDS
  348. how do proviruses work within a host cell?
    they may never activate, but they are never removed and will call the viral dna as long as the cell is alive
  349. what are latent infections?
    virus remains dormant in host cells for long periods of time without symptoms
  350. what is an example of a latent infection?
    herpes viruses - remain latent inside nerves (cold sores, genital herpes, chicken pox)
  351. what are oncogenic viruses (oncoviruses)?
    cancer causing viruses
  352. what is an example of an oncogenic virus?
    human papillomavirus (HPV) causes cervical cancer; hepatitis B (HBV) causes liver cancer
  353. when do cancer causing viruses usually occur?
    the insertion of a provirus disrupts an oncogene
  354. what is an oncogene?
    a gene whose protein helps control cell division, cell can lose control over its cell division
  355. what percent is estimated of cancer is caused by viruses?
    10% of all human cancers
  356. what are prions?
    infectious proteins
  357. what do prions cause?
    spongiform encephalopathies, or spongy brain diseases
  358. why are spongiform encephalopathies called spongy brain diseases?
    infections results in death of brain cells, causes brain to form and fill with fluid and gives the brain a spongy appearance
  359. what an example of a prion?
    scrapie, mad cow disease (bovine spongiform encephalopathy, BSE), Creutzfeldt-Jakob disese, kuru
  360. where does scrapie occur?
    in sheep, this is where the first prion was discovered
  361. how could mad cow disease have been passed to cattle?
    by feeding cattle contaminated sheep parts
  362. what is creutzfeldt-jakob disease?
    most common human prion disease, CJD may have originally been transmitted through contaminated beef infected with neural tissue
  363. kuru affects who? how?
    human in certain new guinea tribes whose burial practices involve eating parts of the deceased
  364. prions are mis-shapen verison of what?
    normal brain proteins
  365. how does transmission of prions usually happen?
    eating meats contaminated with brain or spinal cord tissue
  366. what are viroids?
    infectious rna
  367. how do viroids probably work?
    interfering with normal transcription/translation
  368. so far only what kind of viroids are known?
    plant viroids
  369. what is an example of a plant viroid?
    potato spindle tuber disease, which causes potatoes to grow into an enlongated shape
Card Set
Microbiology Exam 2