BIOL 401 – General Microbiology 3. (A) What is the generation time of a bacterial population that increases from 2 to 128 in two hours? (B) What is the mean growth rate constant (k) in this situation? 4. For a particular bacterial culture, a student counted an average of 12 cells per square in a Petroff-Hausser counting chamber when the optical density at 600 nm is 0.05. If the optical density increases from 0.05 to 0.8 in eight hours, how many cells per mL should now be present in the culture? What is the mean growth rate constant (k) for this culture? 5. You performed spectrophotometric measurements to determine the grow rate of a bacterial cell culture and obtained the data shown below. Please plot the absorbance versus time on a logarithmic (base 10) scale to show the growth curve as a straight line. Find the slope of the line and calculate the generation time from the slope. You will first need to calculate the time elapsed (duration) for some of the data points shown in the table below. Time | Duration (min) | OD600 3:59 AM | 0 | 0.189 4:59 AM | 60 | 0.208 5:59 AM | 120 | 0.227 6:59 AM | 180 | 0.246 7:59 AM | | 0.262 8:59 AM | | 0.280 9:59 AM | | 0.302 10:59 AM | | 0.328 11:59 AM | | 0.357 12:59 PM | | 0.384
Added by Adam M.
Close
Step 1
First, we need to calculate the time elapsed (duration) for some of the data points shown in the table. | Time | Duration (min) | OD600 | |--------|----------------|-------| | 3:59 AM| 0 | 0.208 | | 5:59 AM| 120 | 0.227 | | 8:59 AM| 300 Show more…
Show all steps
Your feedback will help us improve your experience
Madhur L and 86 other Biology educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
Lab Questions: 1. Plot the LOG of the number of living cells in the culture (viable count) using Microsoft Excel. Label the graph with the different phases of growth. (15 Marks) 2. Determine the growth rate and generation time for the particular strain and cultural conditions in our experiment. Remember that the points you need to calculate these values are to be taken from the exponential phase. Show all Lab Questions Continued: 3. The mean division time for a bacterial population is 20 minutes. Calculate how many bacteria will be present after two hours, when starting with 10 bacteria. Show all calculations. (5 marks) 4. If turbidometry readings were also made for the culture described above, draw a labeled diagram to show what the growth curve would look like based on the changes in turbidity with time. Explain the reason for any difference between the growth curve from the viable count and the one for turbidity. (10 Marks) 5. If the culture was producing a valuable product during the stationary phase briefly explain how this phase could be prolonged to get maximum yield of product. (8 Marks)
Josee P.
Part II: Interpreting Data & Drawing Conclusions In the growth curve below, Pseudomonas aeruginosa was grown the OD600 measure hourly over 12 hours. Use the data in the graph and the calculations above to answer the questions below. Notice that the numbers above the data point are the OD600 for that timepoint. 1) At timepoint 8 hours, calculate the population density in CFU/ml (Show your work) 2) Given the data, determine the generation time for this organism during log phase 3) At what time (approximately) does this organism enter Stationary phase? 4) This growth curve was conducted at 37°C, what do you think would happen if the growth curve was conducted at 25°C?
Dominador T.
What is the specific growth rate of a bacterial culture undergoing exponential growth, if the generation time is 27 min? Given the cell count at time zero is Zx10^7/L and the specific growth rate is 0.25/h, determine the cell count after The initial bacterial cell numbers in a batch reactor were measured to be 12,500 cells/L. After 4 hours, the cell numbers were measured to be 34,000/L. For the given reactor, determine: The specific growth rate b. Doubling time. Determine the specific growth rate of a bacterial culture using Monod growth kinetics. Given: the maximum growth rate (Umax) = 3.5/hr, substrate affinity constant (K) = 20 mg/L, substrate concentration of 200 mg/L, and maintenance constant (km) = 0.04/min. Determine the maximum growth rate of Saccharomyces organisms given the glucose concentration of 150 mg/L and half-saturation constant (K) for glucose as 25 mg/L. The cell count at time zero was 3x10^2/L and after 4.5 hours, the cell count was measured to be Zx10^9/L. The maintenance constant (km) is 0.05/min and the decay constant is 0.01/min.
Maitreya E.
Recommended Textbooks
Biology for AP Courses
Objective Biology for NEET
Introduction to General, Organic and Biochemistry
Transcript
18,000,000+
Students on Numerade
Trusted by students at 8,000+ universities
Watch the video solution with this free unlock.
EMAIL
PASSWORD