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In the Phase 2 or P2 of a dilu#on streak, I would expect to find the lowerconcentra#on of bacteria. This is because the microbial concentra#on is diluted andonly 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 phasesrank (from highest to lowest), P1 > P2 > P3 > P4.2 / 2 ptsQues!on 21True or False. When performing a dilu#on streak a new (or sterilized) loop is notrequired 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 ptsQues!on 22The number of phases (3 vs. 4) and/or the number of #mes a loop passes through aprevious 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 previousphase is acceptable and provided that growth of individual colonies is present withinthe resul#ng gradient. If it is not provided, the experiment must be repeated or redonein its en#rety. Either devia!on is acceptable in prac!ce provided the resul!ng gradientcontains within it the growth of individual colonies—if not, the experimentmust be repeated.2 / 2 ptsQues!on 23True 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 ptsQues!on 24When given an unknown bacterial sample the first step is to expand the currentbacterial popula#on. Which form of media best suites this need? Why?1. MSA agar2. LB media containing ampicillin and neomycin3. MacConkey agar4. Blood agarThe form of media that best suites this need is LB agar, or Lysogeny Broth, it is amedia with many purposes, and is capable of growing and producing a wide range ofmicroorganisms. It is a non-selec#ve and non-differen#al media. It is known to growE.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 differen!al media, it is, most importantly,a non-selec!ve media. Given the alterna!ves, this is the best op!on.Quiz Score: 89out of 100"PreviousNext#Submission Details:Time:59 minutesCurrentScore:89 out of100Kept Score:89 out of100HomeModulesGrades