33. Diana used the streak plate procedure to obtain pure cultures of Stevieray's bacterial strains. She decides to generate a growth curve for the novel strain by inoculating a flask of nutrient broth with a single white colony from your streak plate. She removes aliquots from the initial culture to do a plate count for time 0, then incubates the culture at ambient temperature, removing aliquots for optical density measurements at 11-hour intervals for three days. A couple of days later, she collects the data and calculates the cell density for each time point, then plots the following data set: Time (hours) Optical density (at 600 nm) 0 0.020 11 0.141 22 0.502 33 1.887 44 3.499 55 5.035 66 5.243 Chart Title 6.000 5.000 4.000 3.000 2.000 1.000 0.000 0 11 22 33 44 55 66 Time OD600 A) Calculate the number of doublings over the total growth period for the strain. Show all work for full credit. (4 pts) B) Calculate the generation time. Show all work and units for full credit. (6 pts) C) (6 pts) Stevieray has then asked you to dilute the 66-hour timepoint (5.243 OD600) to determine if the cells could be transformed with a plasmid the next morning. He asks you to make a dilution so that he would have 625mL of a 2.25 OD600 culture ready to transform at 11:00 AM. Currently it is 1:00 PM. Assume a 2-hour lag phase. What is the volume of cell culture and media needed for Stevieray's experiment? Show all work and units for full credit.
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The initial OD is 0.020 and the final OD is 5.243. The difference in OD is 5.243 - 0.020 = 5.223. To find the difference in OD for one doubling, we can divide the final OD by 2, since each doubling results in half the OD. So, 5.223 / 2 = 2.6115. Now, we can Show moreā¦
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Time (hours) 0 11 22 33 44 55 66 Optical density at 600 nm 0.020 0.141 0.502 1.887 3.499 5.035 5.243 Chart Title 6.000 5.000 4.000 3.000 2.000 1.000 0.000 A) Calculate the number of doublings over the total growth period for the strain. Show all work for full credit. (4 pts) B) Calculate the generation time. Show all work and units for full credit. (6 pts) C) (6 pts) Stevieray has then asked you to dilute the 66-hour timepoint (5.243 OD600) to determine if the cells could be transformed with a plasmid the next morning. He asks you to make a dilution so that he would have 625mL of a 2.25 OD600 culture ready to transform at 11:00 AM. Currently it is 1:00 PM. Assume a 2-hour lag phase. What is the volume of cell culture and media needed for Stevieray's experiment? Show all work and units for full credit.
Madhur L.
(A) What is the mean growth rate of a particular bacterial culture? (B) How many cells per square inch should be counted in a bacterial culture with an optical density of 0.015? (C) What is the mean growth rate constant (k) for this culture? To determine the growth rate of a bacterial culture, spectrophotometric measurements were performed. The absorbance versus time data is shown below. Please plot the absorbance versus time on a logarithmic scale and calculate the slope of the line. This slope will be used to calculate the generation time. Time (Duration in minutes) Absorbance 0 0.139 3.59 0.262 10.59 0.280 11.59 0.357 12.59 PM 0.384
Sri K.
Lab Activity 1: Table 1 Temperature Conditions Bean Mass (g) 0 min (mL) 5 min (mL) 10 min (mL) 15 min (mL) 20 min (mL) 25 min (mL) 30 min (mL) 4Ā°C 12.14 0.5 0.51 0.53 0.54 0.55 0.55 0.55 Room Temp 15.03 0.65 0.635 0.615 0.575 0.560 0.530 0.525 37Ā°C 15.90 0.55 0.53 0.5 0.47 0.42 0.39 0.33 1. Plot all three time series as line graphs on the same graph in Excel and print it to turn in with your data sheet. Your X-axis should be time, and the Y-axis should be mmĀ³ Oā consumed. 2. Calculate the total volume of Oā consumed in 30 minutes in mL for each temperature. 4Ā°C : 0.5 + 0.51 + 0.53 + 0.54 + 0.55 + 0.55 + 0.55 = 3.73 mL Room temp: 0.65 + 0.635 + 0.615 + 0.575 + 0.560 + 0.530 + 0.525 = 4.09 mL 37Ā°: 0.55 + 0.53 + 0.5 + 0.47 + 0.42 + 0.39 + 0.33 = 3.19 mL 3. Convert these values into mmĀ³. 4Ā°C -> 3730 mmĀ³ Room temp -> 4090 mmĀ³ 37Ā° -> 3190 mmĀ³ 4. What would be the volume (in mmĀ³) of Oā consumed in 1 hour for each temperature? 5. What is the volume of Oā consumed per hour per gram of beans for each temperature? 6. By examining your class data, what trend do you see with regard to temperature and respiration rate? Were the results repeatable from group to group for the same temperature? If there were differences, why might they occur?
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