Reference no: EM1383801

3)      A friend of yours asks you to help him/her draw two bacterial growth curves. He/she gives you the following information: the TA started both cultures (one was labeled culture “X” and the other culture “Y”) at 8:30am using the same overnight culture to inoculate fresh medium. After inoculation of the medium the OD was 0.14 for both cultures and both cultures were incubated at 37 ^oC. During class the following OD readings were obtained: for culture “X”: 0.19 at 9:50am, 0.28 at 10:10am, 0.29 at 10:30, 0.68 at 10:50 am, and 1.1 at 11:10am. At 11:30am the OD of a 1:10 dilution of the stock culture was 0.29. For culture “Y”: 0.16 at 9:50am, 0.19 at 10:10am, 0.21 at 10:30, 0.24 at 10:50 am, 0.28 at 11:10am and 0.32 at 11:30am.A) Draw the two graphs. B) What was the generation time of these cultures? C) What could be the reason for the different growth pattern? Give a detailed explanation!

4)      For a different experiment you are growing up Saccharomyces cerivisiae instead of E.coli. The measured OD is 0.89. A) In order to calculate the concentration of the Saccharomyces cerivisiae culture, can you use the equation that you use to calculate the concentration of an E.coli culture? If yes or no, give adetailed explanation. B) Does E.coli or Saccharomyces cerivisiae have a shorter generation time? Give a detailed explanation!

5)      Your TA gives you an E.coli culture that has a concentration of 2000cells/ml. He/she tells you to evenly spread 25µl of this culture on an LB agar plate and another 25µl on a GMS plate. Both plates are incubated at 37^oC. What do you expect to see the next day and why? Give a detailed explanation!

6)      You want to determine what the optimal pH is for E.coli to grow. How would you set up the experiment? Give a detailed explanation!