In the phase 2 or p2 of a dilu on streak i would

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In the Phase 2 or P2 of a dilu # on streak, I would expect to find the lower concentra # on of bacteria. This is because the microbial concentra # on is diluted and only small amount of the bacterial sample is transferred from phase 1 to phase 2. P4 (Phase 4) would contain the lowest concentra ! on of bacteria. The phases rank (from highest to lowest), P1 > P2 > P3 > P4. 2 / 2 pts Ques ! on 21 True or False. When performing a dilu # on streak a new (or sterilized) loop is not required for each phase as long as the bacterial culture is pure. True False Correct! A new or sterilized loop is absolutely required for each phase. Failure to do so would prevent the establishment of a dilu # on gradient, as the same bacterial concentra # on would be spread across both phase regions, regardless of whether or not the culture is pure. Your Answer: 5 / 5 pts Ques ! on 22 The number of phases (3 vs. 4) and/or the number of # mes a loop passes through a previous phase (once vs. mul # ple # mes) is acceptable provided what happens? The number of phases and or the number of # mes a loop passes through a previous phase is acceptable and provided that growth of individual colonies is present within the resul # ng gradient. If it is not provided, the experiment must be repeated or redone in its en # rety. Either devia ! on is acceptable in prac ! ce provided the resul ! ng gradient contains within it the growth of individual colonies—if not, the experiment must be repeated. 2 / 2 pts Ques ! on 23 True or False. Pathogenic strains of bacteria tend to grow slower than normal non- pathogenic bacterial strains. True False Correct! Correct! Pathogenic strains of bacteria tend to grow faster than non-pathogenic strains at 37°C, which is why researchers may set incubators at 25°C to restrict its growth. Your Answer: 0 / 5 pts Ques ! on 24 When given an unknown bacterial sample the first step is to expand the current bacterial popula # on. Which form of media best suites this need? Why? 1. MSA agar 2. LB media containing ampicillin and neomycin 3. MacConkey agar 4. Blood agar The form of media that best suites this need is LB agar, or Lysogeny Broth, it is a media with many purposes, and is capable of growing and producing a wide range of microorganisms. It is a non-selec # ve and non-di ff eren # al media. It is known to grow E.Coli, a microbe that is known for its ability to produce recombinant proteins. Blood agar. All other op ! ons (A, B and C) are all forms of selec ! ve media, meaning they may poten ! ally inhibit the growth of the unknown sample. Although blood agar is considered a di ff eren ! al media, it is, most importantly, a non-selec ! ve media. Given the alterna ! ves, this is the best op ! on. Quiz Score: 89 out of 100 " Previous Next # Submission Details: Time: 59 minutes Current Score: 89 out of 100 Kept Score: 89 out of 100 Home Modules Grades

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