Term
| 1. What are Bacterial chromosomes made up of? |
|
Definition
|
|
Term
| 2. What form are most (50%) or Bacterial chromosomes in? |
|
Definition
| 2. Single circular molecule, 1-9 Mb |
|
|
Term
| 3. What other forms do bacterial chromosomes take? |
|
Definition
| 3. Single circular molecule, more than one circular molecule, single linear molecule, more than one linear molecule |
|
|
Term
| 4. T/F Extrachromosomal elements are essential for bacterial growth. |
|
Definition
| 4. F – not essential for bacterial growth under normal circumstances |
|
|
Term
| 5. What 2 forms of extrachromosomal elements are there in bacteria? |
|
Definition
| 5. Plasmids, Bacteriophages |
|
|
Term
| 6. What are some variable chromosomal elements that are present in some strains and not others? |
|
Definition
| 6. Integrated Plasmids and bacteriophages, Remnants of plasmids and bacteriophages, transposable elements, Pathogenicity islands |
|
|
Term
| 7. What is a large contiguous block of DNA encoding groups of genes involved in pathogenesis called? |
|
Definition
|
|
Term
| 8. What types of things do Pathogenicity Islands encode for? |
|
Definition
| 8. Virulence factors – toxins, secretion systems, pili, ect. |
|
|
Term
| 9. How can P. Islands be recognized? |
|
Definition
| 9. Often have different G+C content then the rest of the chromosome |
|
|
Term
| 10. How are P. Islands thought to have originated? |
|
Definition
| 10. Horizontal gene transfer |
|
|
Term
| 11. What are the 3 types of Recombination? |
|
Definition
| 11. Homologous, Site-specific, Transposition |
|
|
Term
| 12. Which type of Recombination is used for lambda integration? |
|
Definition
| 12. Site-specific Recombination |
|
|
Term
| 13. Which type is used for generalized transduction, transformation and conjugation? |
|
Definition
|
|
Term
| 14. Which type is used by insertion sequences, transposons, and phage Mu? |
|
Definition
|
|
Term
| 15. How does Site-specific work? |
|
Definition
| 15. Requires very little homology and uses enzymes that recognize apecific sites and recombine them |
|
|
Term
| 16. What type requires host- or phage-encoded homologous recombination proteins? |
|
Definition
| 16. Homologous Recombination |
|
|
Term
| 17. What type involves insertion of transposable elements into different hon-homologous sites in the host DNA? |
|
Definition
|
|
Term
| 18. What are the 3 regions of the prokaryotic gene? |
|
Definition
| 18. Regulatory Region, Coding Region, Termination Region |
|
|
Term
| 19. What codes for the protein to begin? |
|
Definition
| 19. Initiator Codon – ATG |
|
|
Term
| 20. When does the mRNA begin coding? |
|
Definition
|
|
Term
| 21. Where does the ribosome bind? |
|
Definition
|
|
Term
| 22. What region has the most base pairs? |
|
Definition
| 22. Coding region 300-3000bp |
|
|
Term
| 23. What else is within some genes in the regulatory region? |
|
Definition
| 23. Repressor binding sites, activator binding sites |
|
|
Term
| 24. What do most isolated genes have? |
|
Definition
| 24. Promoter and terminator |
|
|
Term
| 25. What is a DNA segment that when transcribed produces a single mRNA which encodes for more than one polypeptide called? |
|
Definition
|
|
Term
|
Definition
| 26. A segment of DNA encoding a single polypeptide |
|
|
Term
| 27. What is a Regulon? Example? |
|
Definition
| 27. Single regulatory protein that affects multiple operons; the arginine biosynthetic regulon |
|
|
Term
| 28. What is it called when multiple genes and operons are controlled by a single stimulus? Example? |
|
Definition
| 28. Stimulon; heat shock, cold shock |
|
|
Term
| 29. T/F Transcription and Translation in Prokaryotes is coupled. |
|
Definition
|
|
Term
| 30. How does the direction of transcription correspond to the lengths of the mRNA transcripts? |
|
Definition
| 30. The more laden with ribosome the transcript the earlier they were transcribed |
|
|
Term
| 31. How is Transcription and Translation coupled? |
|
Definition
| 31. Ribosomes bind in succession to the nascent mRNA molecule and begin translation while the mRNA is being transcribed from the DNA. mRNA degradation follows close behind. |
|
|
Term
| 32. What is the process of Translation of an mRNA? |
|
Definition
| 32. Ribosome recognizes a binding site (rbs) around 6-9 bp upstream of initiation codon (AUG), Translation of gene until Stop codon is reached. At the end of the mRNA will be a transcription terminator. |
|
|
Term
| 33. Do prokaryotic genes have introns? |
|
Definition
| 33. No – the gene and the polypeptide product are collinear |
|
|
Term
| 34. T/F many bacterial genes are grouped into multicistronic operons. |
|
Definition
|
|
Term
| 35. What does a cistron/gene encode for? |
|
Definition
|
|
Term
| 36. What is the difference in Transcription and Translation between Eukaryotes and Prokaryotes? |
|
Definition
| 36. Prokaryotes – coupled, translation begins before the entire mRNA is transcribed; Eukaryotes – the mRNA must leave the nucleus to be translated in cytoplasm |
|
|
Term
| 37. What does the prokaryotic mRNA lack on its 5’ and 3’ ends that eukaryotic mRNA has? |
|
Definition
| 37. 5’ 7-methyl GTP cap, 3’ poly-A tail |
|
|
Term
| 38. What are prokaryotic proteins initiated with? |
|
Definition
|
|
Term
| 39. What does N-formylated peptides act as? |
|
Definition
| 39. Chemoattractants for neutrophils and monocytes |
|
|
Term
|
Definition
| 40. Changes in the DNA sequence, change the genotype, may or may not change the phenotype |
|
|
Term
| 41. What are the 5 types of Mutations? |
|
Definition
| 41. I. Base substitution mutation; II. Frameshift mutations; III. Large deletions; IV. Large insertions; V. Large inversions or translocations |
|
|
Term
| 42. What is a transition? |
|
Definition
| 42. Purine à Purine (G àA) Pyrimidine àPyrimidine (Cà T) |
|
|
Term
| 43. What is a Transversion? |
|
Definition
| 43. Purine to Pyrimidine (G or A à C or T) Pyrimidine to Purine (C or T à G or A) |
|
|
Term
| 44. What is a missense mutation? |
|
Definition
| 44. Protein function altered by incorporation of a different amino acid |
|
|
Term
| 45. What is a Nonsense mutation? |
|
Definition
|
|
Term
| 46. What is a mutation called that is an insertion of deletion of one or two bases? |
|
Definition
|
|
Term
| 47. What would characterize a Large deletion? |
|
Definition
| 47. hundreds to thousands of contiguous bases are lost, leading to severely defective or undetectable proteins |
|
|
Term
| 48. What are large insertions caused by? |
|
Definition
| 48. insertion of transposable element |
|
|
Term
| 49. If large inversions or translocations are not genetically programmed, what can they cause? |
|
Definition
| 49. severe defects in protein function |
|
|
Term
| 50. What are 2 examples of spontaneous mutations? |
|
Definition
| 50. 1. mistakes made during DNA replication and repair; 2. Mutations caused by natural exposure to mutagens. |
|
|
Term
| 51. What are some examples of Natural Mutagens? |
|
Definition
| 51. UV light, cosmic rays, heat, transposable elements |
|
|
Term
| 52. What are some examples of purposeful mutagens? |
|
Definition
| 52. X-rays, UV light, chemical mutagens, transposable elements |
|
|
Term
| 53. At what frequency to mutations caused by purposeful exposure to mutagens occur? |
|
Definition
|
|
Term
| 54. What DNA repair system is highly error-prone? |
|
Definition
|
|
Term
| 55. What is the frequency of mistakes made during DNA replication and repair? |
|
Definition
|
|
Term
| 56. What are 3 regulatory Mechanisms? |
|
Definition
| 56. 1) Change in the DNA sequence; 2) transcriptional regulation; 3) posttranscriptional regulation |
|
|
Term
| 57. What are used in transcriptional regulation? |
|
Definition
| 57. Activators and Repressors |
|
|
Term
| 58. What are 3 forms or posttranscriptional regulation? |
|
Definition
| 58. Covalent modification, proteolytic cleavage, binding to host cell proteins |
|
|
Term
| 59. What is it called when an effector molecule binds a protein altering its ability to interact with its substrate? |
|
Definition
|
|
Term
| 60. What is a regulatory protein called that turns ON the genes when bound to DNA? |
|
Definition
|
|
Term
|
Definition
| 61. regulatory protein that turns genes OFF when bound to DNA |
|
|
Term
| 62. What is a chemical called that when bound to the regulatory protein turns genes ON? |
|
Definition
|
|
Term
| 63. What is a Negative regulation caused by binding of a chemical to the regulatory protein called? |
|
Definition
|
|
Term
| 64. How are catabolic operons usually regulated? |
|
Definition
| 64. positive regulation, (the default state is off) |
|
|
Term
| 65. What type of operons are often negatively regulated? |
|
Definition
| 65. Biosynthetic operons (default state is on) |
|
|
Term
| 66. How is regulation by small molecules accomplished? |
|
Definition
| 66. by the concentration dependence of binding of the small molecules to the regulatory proteins. |
|
|
Term
| 67. How do bacteria use catabolite repression? |
|
Definition
| 67. distinguish between good and poor carbon sources and repress the lac operon gene until all the glucose is used up. |
|
|
Term
| 68. How is catabolite repression mediated? |
|
Definition
| 68. concentration of cAMP, inversely related to glucose levels. (Glucose High – cAMP low; Glucose low – cAMP high) |
|
|
Term
| 69. What regulatory protein is involved in catabolite repression? |
|
Definition
| 69. Cabolite Activator Protein (CAP) (also called CRP – cAMP receptor protein) |
|
|
Term
| 70. Where does CAP bind and what kind of regulatory protein is it? |
|
Definition
| 70. Promoter region of lac operon; activator protein |
|
|
Term
| 71. What does CAP interact with? |
|
Definition
| 71. RNA polymerase and turns on transcription |
|
|
Term
| 72. T/F CAP alone can bind to the promoter DNA. |
|
Definition
| 72. F – Only CAP in a cAMP-CAP complex can bind to DNA. |
|
|
Term
| 73. What is the monitor of cAMP levels? |
|
Definition
|
|
Term
| 74. What is the lac operon transcribed from the promoter as? |
|
Definition
|
|
Term
| 75. How does the absence of the inducer prevent lac mRNA transcription? |
|
Definition
| 75. Lac repressor binds to operator |
|
|
Term
| 76. What is the inducer of the Lac Operon called? |
|
Definition
|
|
Term
| 77. In the presence of allolactose what happens? |
|
Definition
| 77. binds to repressor, causes conformational change that makes the repressor unable to bind to operator DNA |
|
|
Term
| 78. Once the repressor is inactivated why are only a small number of transcripts made? |
|
Definition
|
|
Term
| 79. What happens in the absence of both glucose and lactose? |
|
Definition
| 79. High cAMP levelsàbinds to CAPà cAMP-CAP complex binds to the promoter, BUT no Lactose so no Inducer (allolactos), so repressor stays bound to operator, No Transcription, No lac mRNA |
|
|
Term
| 80. What happens in the presence of Lactose but the absence of glucose? |
|
Definition
| 80. Lac repressor binds inducer, cAMP binds CAP, cAMP-CAP complex binds promoter causeing high levels of transcription |
|
|
Term
| 81. What is the Trp Operon? |
|
Definition
| 81. encodes the five enzymes needed for biosynthesis of amino acid tryptophan. |
|
|
Term
| 82. What is the leader peptide and where is it located? |
|
Definition
| 82. contains 2 tryptophans near its C-terminus; between the operator and the first gene. |
|
|
Term
| 83. What is the default condition of the Trp Operon? |
|
Definition
| 83. ON, it’s a biosynthetic operon |
|
|
Term
| 84. What causes the repressor protein to become active and bind the operator? |
|
Definition
|
|
Term
| 85. In High concentrations of Trp how is the leader mRNA translated? |
|
Definition
| 85. quickly, preventing the stable 2-3 hairpin, and leading to the formation of the 3-4 hairpin that serves as a terminator. |
|
|
Term
| 86. What occurs at low concentrations of Trp? |
|
Definition
| 86. ribosomes stall at the 2 trp codons, allowing the 2-3 hairpin to form an anti-terminator structure, allowing transcription to proceed. |
|
|
Term
| 87. What do hairpin 1-2 and 3-4 cause and why? |
|
Definition
| 87. termination; no protein synthesis |
|
|
Term
| 88. What do virulence factors do? |
|
Definition
| 88. foster survival and multiplication in the host |
|
|
Term
| 89. What type of signals do Bordetella pertussis us for virulence gene expression? |
|
Definition
| 89. temperature, SO4, nicotinic acid |
|
|
Term
| 90. What type of organisms use Iron as a Signal? |
|
Definition
| 90. Corynebacterium diphtheria, E. Coli, Pseudomonas aeruginosa |
|
|
Term
| 91. How does the Two-Component Regulatory system work? |
|
Definition
| 91. The sensor and transducer are phosphorylated by a signal, the P-Transducer activates transcription |
|
|
Term
| 92. What is Quorum Sensing? |
|
Definition
| 92. the ability of the cell to sense the cell density |
|
|
Term
| 93. What do bacterial pathogens use quorum sensing for? |
|
Definition
| 93. to co-ordinate their expression of virulence genes in order to evade the immune response |
|
|
Term
| 94. What can be used to interfere with quorum sensing? |
|
Definition
|
|
Term
| 95. What is quorum sensing especially important in forming? |
|
Definition
|
|
Term
| 96. What are 3 reasons why Gene Transfer in Bacteria are medically important? |
|
Definition
| 96. 1) spread of antibiotic resistance; 2) exchange of virulence factors; 3) antigenic variation |
|
|
Term
| 97. T/F Gene transfer is rare. |
|
Definition
| 97. T – varies from 10-2 to 10-6 per cell |
|
|
Term
| 98. What is Transformation? |
|
Definition
| 98. the transfer of genetic information from one cell to another via naked DNA |
|
|
Term
| 99. What are some examples of bacteria that can naturally transform? |
|
Definition
| 99. Gram Negative – Campylobacter spp, Haemophilus influenza, Neisseria meningitides Gram Positive – Bacillus subtilis, Clostridium botulinum, Strep. pneumoniae |
|
|
Term
| 100. What is the ability to bind and take up DNA called? |
|
Definition
|
|
Term
| 101. How is DNA structured during uptake into the recipient cell in natural transformation? |
|
Definition
|
|
Term
| 102. What 2 forms of artificial Transformation uptake DNA in an intact form? |
|
Definition
| 102. Induced and Electroporation |
|
|
Term
| 103. What is an example of Induced transformation? |
|
Definition
| 103. high salt and heat shock for E. Coli |
|
|
Term
| 104. What happens in Electroporation? |
|
Definition
| 104. cells exposed to short burst of high electric field that transiently permeabilizes the cells and causes them to take up molecules for the surrounding medium |
|
|
Term
| 105. T/F Competence is involved in Electroporation. |
|
Definition
|
|
Term
| 106. What are the steps in the Gram Positive Species Transformation Process? |
|
Definition
| 106. 1) DNA released from cell; 2) DNA binds to cell surface receptor and taken up into the cell, 1 strand is degraded; 3) single strand invades its homologous region and displaces one original strand; 4) heteroduplex is replicated, producing 1 tranformant and one unaltered recipient genome; 5) Close genetic markers can be transformed together on a single DNA fragment |
|
|
Term
| 107. What are the 2 exceptions in Gram-Negative Transformation? |
|
Definition
| 107. 1) DNA binding requires specific sequences in the double-stranded DNA in order to bind the receptor. 2) DNA is taken up in a double-stranded form in a membrane vesicle. |
|
|
Term
| 108. What is the membrane vesicle called? |
|
Definition
|
|
Term
| 109. What involves the direct transfer of genetic information form one cell to another via cell to cell contact? |
|
Definition
|
|
Term
| 110. What does conjugation require? |
|
Definition
| 110. cell to cell contact and specific surface proteins |
|
|
Term
| 111. T/F Conjugation is not DNase resistant. |
|
Definition
| 111. F – it is DNase resistant |
|
|
Term
| 112. How is the ability to promote conjugation usually endoded? |
|
Definition
| 112. by a plasmid in the donor cell |
|
|
Term
|
Definition
| 113. covalently closed, circular, supercoiled DNA molecules that replicate autonomously |
|
|
Term
| 114. How are plasmids inherited? |
|
Definition
| 114. stably in an extrachromosomal state |
|
|
Term
| 115. Are plasmids essential? |
|
Definition
| 115. No, they are “extra DNA” sometimes lost |
|
|
Term
| 116. What are a few types of genes that plasmids can carry? |
|
Definition
| 116. antibiotic resistance, toxin production, metal ion resistance, virulence factors, bacteriocin production, etc. |
|
|
Term
| 117. What is the Incompatibility property of plasmids? |
|
Definition
| 117. prevents 2 related plasmids from stably replicating in the same cell |
|
|
Term
| 118. What prevents entry of a plasmid into a cell that already had a closely related plasmid? |
|
Definition
|
|
Term
| 119. Are unrelated plasmids affect by Incompatibility and Surface exclusion? |
|
Definition
|
|
Term
| 120. What is the Host Range? |
|
Definition
| 120. host in which a plasmid can replicate |
|
|
Term
| 121. How is the copy number determined? |
|
Definition
| 121. by the plasmid replication system, no the plasmid size |
|
|
Term
| 122. T/F – Often small plasmids have a high copy number whereas large plasmids usually have a low copy number. |
|
Definition
|
|
Term
| 123. What type of plasmids have the ability to promote their own transfer from one cell to another? |
|
Definition
| 123. Conjugative plasmids |
|
|
Term
| 124. Are Non-conjugative plasmids able to promote their own transfer? |
|
Definition
|
|
Term
| 125. What are the 2 types of non-conjugative plasmids? |
|
Definition
| 125. Mobilizable and Non-mobilizable |
|
|
Term
| 126. How are mobilizable plasmids transferred? |
|
Definition
| 126. can’t transfer themselves but can be mobilized to transfer by another conjugative plasmid in the same cell. |
|
|
Term
| 127. How are Mobilizable plasmids classified? |
|
Definition
|
|
Term
| 128. T/F Non-mobilizable plasmids can’t transfer under any condition. |
|
Definition
| 128. T – they are oriT (origin of transfer) defective |
|
|
Term
| 129. What confers the ability of F factor of E. Coli to integrate into the host chromosome? |
|
Definition
|
|
Term
| 130. What type of cells are good recipients for DNA transfer by conjugation because they have no F factor? |
|
Definition
|
|
Term
| 131. What type of cells have an extrachromosomal F factor? |
|
Definition
|
|
Term
| 132. Which type of cells have the F factor integrated into the chromosome? |
|
Definition
|
|
Term
| 133. How is the F Factor in the F’ cell? |
|
Definition
| 133. the extrachromosomal F factor also carries some chromosomal genes incorporated during aberrant excision of an integrated plasmid |
|
|
Term
| 134. What are the steps in Transfer of an F Plasmid by conjugation? |
|
Definition
| 134. 1) F pilus of donor cell contact recipient cell, pulls it in; 2) conjugation bridge formed, plasmid DNA nicked at oriT; 3) DNA replicated by rolling circle replication, 5’ end transferred through conjugation bridge, complementary strand made; 4) complete transferred plasmid circularizes and become stable; 5) Conjugation bridge breaks. |
|
|
Term
| 135. What are the steps of Chromosomal DNA transfer by an Hfr? |
|
Definition
| 135. 1) Hfr cell contacts recipient (F-) cell with F pilus, forms conjugation bridge; 2) Nicking oriT, rolling circle replication, 5’ end transferred; 3) conjugation bridge breaks before circularization sequence is transferred; 4) Transferred strand find homologue in recipient chromosome and recombines into it. |
|
|
Term
| 136. How does Conjugation occur in Gram-Positive bacteria? |
|
Definition
| 136. recipient cells make small peptide pheromones, causing donor cells to make adhesions and cells clump, conjugation bridges form. |
|
|
Term
| 137. T/F pheromones are specific for plasmids. |
|
Definition
|
|
Term
| 138. What can the IS element serve as? |
|
Definition
| 138. a region of homology for recombination into the host chromosome |
|
|
Term
| 139. How can homologous recombination lead to excision or inversion of the intervening DNA? |
|
Definition
| 139. depending on the relative IS orientation |
|
|
Term
| 140. How does Amplification of Resistance work? |
|
Definition
| 140. Increased number of drug resistance genes integrated into the cell confer resistance to a higher concentration of antibiotics |
|
|
Term
|
Definition
| 141. discrete DNA elements that carry promoterless antibiotic resistance genes |
|
|
Term
| 142. How do integrons integrate? |
|
Definition
| 142. specific sites and do not encode a transposase |
|
|
Term
| 143. More multi-drug resistant plasmids may be generated by what? |
|
Definition
|
|
Term
| 144. What are bacteriophages? |
|
Definition
| 144. viruses that infect bacteria |
|
|
Term
| 145. How are phages organized? |
|
Definition
| 145. particles are composed of a single molecule of nucleic acid which is protected by a protein coat. |
|
|
Term
| 146. What are the 2 types of Lifestyles phages can take? |
|
Definition
| 146. Virulent and Temperate |
|
|
Term
| 147. What lifestyle results in the production of more phage particles through lytic development? |
|
Definition
|
|
Term
| 148. What 2 outcomes can result from a Temperate Phage? |
|
Definition
| 148. 1) lytic development and progeny phage production. 2) formation of lysogen containing a repressed prophage. |
|
|
Term
| 149. What is used by phages for adsorbing to their host cells? |
|
Definition
|
|
Term
| 150. What are the steps in Lytic Development? |
|
Definition
| 150. 1) Adsorption; 2) Injection of DNA; 3) Transcription of phage DNA; 4) Phage proteins made, phage DNA replicated, conversion of bacterium to phage factory; 5) “Factory” produces Phage structures; 6) DNA packaged into phage; 7) Lysis … Repeat |
|
|
Term
| 151. How can phages be detected in an agar plate? |
|
Definition
|
|
Term
| 152. What are the steps in Lysogen Formation with Integration? |
|
Definition
| 152. 1) Phage DNA injected into bacterium; 2) Lytic functions turned off in phage mRNA synthesis by Repressor; 3) Phage DNA molecule inserted into chromosome of bacterium by Integrase protein; 4) bacterium grows and divides with phage genes as part of bacterial chromosome |
|
|
Term
| 153. T/F – Lysogen Formation with Replication as a Plasmid integrates the phage DNA into the bacterial DNA. |
|
Definition
| 153. F – There is no integrase or integration, the phage DNA replicates at a low level as a plasmid |
|
|
Term
| 154. How does Induction of an integrated prophage or a plasmid prophage take place? |
|
Definition
| 154. destruction of the phage repressor protein |
|
|
Term
| 155. T/F – All Lysogens are immune to superinfection |
|
Definition
|
|
Term
| 156. What can lysogenic conversion do? |
|
Definition
| 156. alter cell wall properties and provide new phage resistances |
|
|
Term
| 157. What phage of C. diphtheria carries the tox gene which encodes diphtheria toxin? |
|
Definition
|
|
Term
| 158. What phage encodes for SPE’s responsible for scarlet fever? |
|
Definition
|
|
Term
| 159. What phage encodes a Shiga-like toxin? |
|
Definition
|
|
Term
| 160. T/F – Infection by a non-toxigenic strain of C. botulinum with a phage that encodes a toxin can convert the strain to a virulent strain that produces the toxin. |
|
Definition
|
|
Term
| 161. What is Transduction? |
|
Definition
| 161. the transfer of genetic material by a phage particle |
|
|
Term
| 162. What are the 2 types of Transduction? |
|
Definition
| 162. Generalized and Specialized |
|
|
Term
| 163. Which type of Transduction occurs by mistaken packaging of a piece of host DNA into a phage particle instead of a phage DNA? |
|
Definition
|
|
Term
| 164. How does Specialized Transduction occur? |
|
Definition
| 164. aberrant excision of a prophage leading to incorporation of a small piece of host DNA into the phage genome |
|
|
Term
| 165. What is abortive transduction? |
|
Definition
| 165. formation of microcolonies instead of normal-sized colonies because the transduced DNA circularizes and only passed to 1 of 2 daughter cells. |
|
|
Term
| 166. What does Excision of Lambda DNA require? |
|
Definition
| 166. integrase and XIS proteins |
|
|
Term
| 167. What is Lambda integration catalyzed by? |
|
Definition
|
|
Term
| 168. What are λdgal phages defective for? |
|
Definition
| 168. growth and plaque formation |
|
|
Term
| 169. What is provided to help the phages with missing function grow? |
|
Definition
|
|
Term
| 170. What are High Frequency Transducing lysate (HFT)? |
|
Definition
| 170. a transductant that arises by lysogenization with both a transducing phage and a normal helper phage |
|
|
Term
| 171. What is the size of DNA transferred by Transduction? |
|
Definition
| 171. 1-2% of the chromosome |
|
|
Term
| 172. What transfers medium sized pieces of DNA, 5-10% of chromosome? |
|
Definition
|
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Term
| 173. How big are pieces of DNA that are transferred with conjugation? |
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Definition
| 173. 25-50% of chromosome |
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Term
| 174. What is a Transposable element? |
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Definition
| 174. discrete segments of DNA that move from one site to another in a genome without a requirement for DNA sequence homology |
|
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Term
| 175. What is Transposition catalyzed by? |
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Definition
|
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Term
| 176. What do all transposable elements (TE) have? |
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Definition
| 176. short (15-30bp) inverted repeats |
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Term
| 177. What are a type of TE with short inverted repeats at ends and no detectable phenotypes? |
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Definition
| 177. Insertion sequences, IS |
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Term
| 178. What are Type 1 composite transposons? |
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Definition
| 178. large elements with long repeats at the ends and unique DNA in the middle, usually antibiotic resistance |
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Term
| 179. Which type of TE has ends that cannot transpose independently? |
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Definition
| 179. Tn3-like transposons |
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Term
| 180. What type of TE has the ability to cause mutation by insertion into host genes? |
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Definition
|
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Term
| 181. What part of the TE binds the transposase? |
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Definition
| 181. short inverted repeats at the ends |
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Term
| 182. How can insertion into a gene disrupt the gene function? |
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Definition
| 182. can eliminate function of downstream genes by polarity |
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Term
| 183. How does simple transposition work? |
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Definition
| 183. Tn from replicon 1 adds on to replicon 2 |
|
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Term
| 184. What happens in Replicative transposition? |
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Definition
|
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Term
| 185. How does Replicative transposition and resolution work? |
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Definition
| 185. R1 and R2 add together and replicate and cointegrate, then separate back down to separate R1 and R2 each with Tn. |
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Term
| 186. T/F – conjugative transposons can transfer between Gram+ and Gram- bacterial species. |
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Definition
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Term
| 187. What are some examples of Diagnostic Methods? |
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Definition
| 187. Direct Examination, Culture, Antibody Detection, Detection of Microbial Components or Metabolites, Genome Detection |
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Term
| 188. How can a direct specimen be taken? |
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Definition
| 188. when pathogen is located in an otherwise sterile site, abscess, collected surgically or by needle aspiration |
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Term
| 189. What is a specimen called that is in a sterile site but must pass through a site containing normal flora to be collected? |
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Definition
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Term
| 190. How is a Sample taken from a site with normal flora? |
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Definition
| 190. Sample collected is a mixture, normal flora are inhibited under growth conditions for analysis. |
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Term
| 191. What are a few guidelines for Specimen Selection, Collection, and Transport? |
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Definition
| 191. Select from active infection, minimize contamination, collect before antimicrobial therapy, minimize time from collection to assay…. etc. |
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Term
| 192. How does an Agglutination Assay work? |
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Definition
| 192. Antibody is bound by its Fc receptor end to the protein A on the surface of dead Staph. A. Visible agglutination is produced when these particles combine with a soluble antigen or another particulate antigen. |
|
|
Term
| 193. How does Direct Immunofluorescence work? |
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Definition
| 193. 1) Acetone-fixed cells on slide; 2) Add fluorescein-conjugated antiserum and incubate; 3) Wash unattached antibody; 4) Exam for fluorescence under UV illumination |
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Term
| 194. What is different about Indirect Immunofluorescence? |
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Definition
| 194. Rabbit antibody added first which is pathogen specific, then fluorescein-labeled goat anti-rabbit antibody is added, then viewed under UV light. |
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Term
| 195. What type of enzymes are used in Enzyme-linked Assays? |
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Definition
| 195. Horseradish peroxidase, Alkaline Phosphatase, Beta-galactosidase |
|
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Term
| 196. How are ELISA Assays reported? |
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Definition
| 196. titer reported is the highest serum dilution that still gives a detectable Ag-Ab reaction based on the color observed. |
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Term
| 197. What is the Western Blot used for in detection of Anti-HIV Ab in serum? |
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Definition
| 197. Distiguishes false positive ELISA vs True positive |
|
|
Term
| 198. Why are DNA Probes convenient for detection? |
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Definition
| 198. Probe is pathogen specific and commercially available. |
|
|
Term
| 199. What are some advantages of PCR? |
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Definition
| 199. more sensitive than direct hybridization, need very small amount of DNA in specimen, very fast |
|
|
Term
| 200. What are some disadvantages of PCR? |
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Definition
| 200. Expense, false positives, false negatives |
|
|
Term
| 201. When should PCR be used? |
|
Definition
| 201. for pathogens with no existing test, poor tests, or diseases with low antigen and antibody production |
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|
Term
| 202. What are some examples of pathogens that PCR is used to detect? |
|
Definition
| 202. hepatitis B, Chlamydia trachomatis, Neisseria gonorrhoeae, HIV, Lyme disease |
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|
Term
| 203. What does Amplicon Detection by Real-Time PCR use? |
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Definition
| 203. DNA intercalating dyes or fluorogenic DNA probes |
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Term
| 204. How is contamination reduced in Amplicon Detection by R-T PCR? |
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Definition
| 204. Amplification and detection are done simultaneously in a closed system. |
|
|
Term
| 205. Order the following from fastest to slowest time it takes for results: |
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Definition
|
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Term
|
Definition
| 206. Obligate intracellular parasites that replicate by self-assembly of individual components rather than by binary fission. |
|
|
Term
| 207. Can Viruses make energy or proteins by themselves? |
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Definition
|
|
Term
| 208. T/F – viruses contain a genome with RNA and DNA. |
|
Definition
| 208. F – contain a genome of limited size that is either RNA or DNA, never both. |
|
|
Term
| 209. How are viruses classified? |
|
Definition
| 209. 1. Size; 2. morphology; 3. type of genome; 4. mechanism of replication. (physical and biochemical characteristics) |
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|
Term
| 210. How can virus genomes be structured? |
|
Definition
| 210. 1. circular or linear ss RNA |
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|
Term
| 211. What is the protein shell that packages the virus genome? |
|
Definition
|
|
Term
| 212. What 3 forms can capsids be in? |
|
Definition
| 212. icosahedral (spherical) , helical, complex |
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|
Term
| 213. Capsids are the result of self-assembly of what? |
|
Definition
| 213. virally-encoded capsomeres |
|
|
Term
| 214. How is the shape of the capsid dictated? |
|
Definition
| 214. by the capsomeres that self-assemble, not the shape of the genome. |
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|
Term
| 215. What makes up a nucleocapsid? |
|
Definition
|
|
Term
| 216. Why are enveloped viruses less stable than naked viruses? |
|
Definition
| 216. a. more susceptible to drying |
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|
Term
| 217. How do enveloped viruses spread? |
|
Definition
| 217. large droplets, secretions, organ transplants, blood transfusions. |
|
|
Term
| 218. How many families of DNA viruses are there? RNA viruses? |
|
Definition
|
|
Term
| 219. What are the major steps in viral replication? |
|
Definition
|
|
Term
| 220. What are the 6 viral cytopathogenesis? |
|
Definition
| 220. 1. Inhibition of cellular protein synthesis |
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|
Term
| 221. Can the +RNA virus genome function as mRNA? |
|
Definition
| 221. Yes – and is immediately translated by cellular ribosomes |
|
|
Term
| 222. How are –RNA virus genomes used? |
|
Definition
| 222. must be used as a template to transcribe a +RNA strand |
|
|
Term
| 223. How do retroviruses function? |
|
Definition
| 223. carry a RNA-dependent DNA polymerase (reverse transcriptase), +RNA genome is reverse transcribed into dsDNA and integrated into host genome |
|
|
Term
| 224. How are DNA virus genomes transcribed? |
|
Definition
| 224. By host DNA-dependent RNA polymerase |
|
|
Term
| 225. What do viruses use to redirect host polymnerases to viral genes and away from cellular genes? |
|
Definition
| 225. specific transcription factors |
|
|
Term
| 226. What do larger viruses depend of for viral genome replication? |
|
Definition
| 226. virally-encoded DNA-dependent DNA polymerases |
|
|
Term
| 227. Do smaller viruses need this? |
|
Definition
| 227. No, they use host DNA polymerase |
|
|
Term
| 228. How are plaques formed? |
|
Definition
| 228. virus infected cells are lysed and leave a “hole” in a confluent monolayer |
|
|
Term
|
Definition
| 229. the suspension of virions in culture medium that results from unrestricted growth of the virus on a cell monolayer |
|
|
Term
| 230. T/F – all virus particles produced in a lysate are infectious. |
|
Definition
| 230. F – particle-to-pfu ratio measure the number of physical particles compared to the number of infectious virions |
|
|
Term
| 231. What do Plaque assays measure? |
|
Definition
| 231. the number of infectious virions in a given volume of lysate. |
|
|
Term
| 232. What is the Multiplicity of Infection (MOI)? |
|
Definition
| 232. the ratio of the number of infectious particles to the number of target cells to be infected. |
|
|
Term
| 233. What MOI is needed to ensure that all cells are infected? |
|
Definition
|
|
Term
| 234. What corresponds to the eclipse period of the single-cycle growth curve? |
|
Definition
| 234. post-penetration phase until virus can be detected intracellulary; corresponds to uncoating, early transcription, and genome replication steps; |
|
|
Term
| 235. When does the eclipse period end? |
|
Definition
|
|
Term
| 236. When does the latent period take place? |
|
Definition
| 236. post-penetration phase until virus can be detected extracellularly |
|
|
Term
| 237. What does the latent period correspond to? |
|
Definition
| 237. uncoating, early transcription, genome replication, virus assemble, and release |
|
|
Term
| 238. T/F – the latent period includes the eclipse period. |
|
Definition
|
|
Term
| 239. Why do viral mutation occur at high frequencies? |
|
Definition
| 239. large number of genome copies produced in every infected cell, and polymerase errors |
|
|
Term
| 240. What step of viral genetics involves exchange of proteins? |
|
Definition
|
|
Term
| 241. What happens in Recombination? |
|
Definition
| 241. An exchange of genetic material on the same segment of genome. |
|
|
Term
| 242. Does recombination occur with both DNA and RNA? |
|
Definition
| 242. DNA – yes occurs frequently |
|
|
Term
| 243. What is the process called that is an exchange of genetic material on different segments of genome? |
|
Definition
|
|
Term
| 244. What are some things to consider about virus-host interactions? |
|
Definition
| 244. route of transmission, secondary spread, incubation period, acute vs. persistent infection, control |
|
|
Term
| 245. What is the most common rout of infection? |
|
Definition
|
|
Term
| 246. What are 2 ways viruses are spread? |
|
Definition
| 246. release of virus from infected cell or syncytia formation |
|
|
Term
| 247. What is syncytia formation? |
|
Definition
| 247. enveloped viruses can fuse an infected cell with uninfected cells to directly spread to surrounding cells |
|
|
Term
|
Definition
| 248. presence of virions in blood |
|
|
Term
| 249. What is the minimum incubation period for viruses that require secondary spread? |
|
Definition
|
|
Term
| 250. T/F – patients can be infection during the incubation period. |
|
Definition
|
|
Term
| 251. What phase of an infection is the symptomatic phase? |
|
Definition
|
|
Term
| 252. What are the 3 froms of persistent infection? |
|
Definition
| 252. Chronic, latent, transforming |
|
|
Term
| 253. What is an example of a latent virus? transforming virus? |
|
Definition
|
|
Term
| 254. What is the first defense in nonspecific immune response? |
|
Definition
| 254. natural killer cells and IFN |
|
|
Term
| 255. What are 3 types of antivirals available? |
|
Definition
| 255. vaccines, immune globulin, drugs |
|
|
Term
| 256. What are the 3 basic types of viral vaccines? |
|
Definition
| 256. live, attenuated virus; killed virus; subunit (recombinant DNA) |
|
|
Term
| 257. What is the challenge of antiviral drugs? |
|
Definition
| 257. viruses are parasites and use much of our own cellular processes, Drugs toxic to Viruses can be toxic to us. |
|
|
Term
| 258. What drug inhibits uncoating of picornaviruses? |
|
Definition
|
|
Term
| 259. What drug inhibits uncoating of influenza A and how does it work? |
|
Definition
| 259. amantadine and rimantadine; inhibits a viral ion channel |
|
|
Term
| 260. What does IFN-alpha inhibit in hepatitis B and C and HPV? |
|
Definition
| 260. transcription and translation |
|
|
Term
| 261. How is translation of CMV mRNA inhibited? |
|
Definition
| 261. a specific antisense RNA |
|
|
Term
| 262. What do the majority of antivirals target and what are they composed of? |
|
Definition
| 262. DNA replication; nucleotide analogs that inhibit viral DNA polymerases or prevent chain elongation |
|
|
Term
| 263. How do protease inhibitors work? |
|
Definition
| 263. prevent polyprotein cleavage and virus assembly by acting as alternative substrates |
|
|
Term
| 264. What does ribavirin do? |
|
Definition
| 264. inhibits nucleoside biosynthesis and as a result inhibits mRNA cap formation and inhibits some RNA polymerases. |
|
|
Term
| 265. What is ribavirin used for? |
|
Definition
| 265. Hepatitis C, Flu and respiratory syncytial virus |
|
|
Term
| 266. What inhibits flu A and B neuraminidase? |
|
Definition
|
|
Term
| 267. What do inhibitor cocktails do? |
|
Definition
| 267. decrease the chances of encountering a resistant strain |
|
|
Term
| 268. T/F – Combination therapies appear to be synergistic. |
|
Definition
|
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