Consider the following graph depicting the population growth of bacteria in an "ideal" laboratory created condition. Explain what conditions would allow for a population to grow exponentially like in this example, and why this is unlikely to occur naturally in the wild. Population (number of bacteria) 35000 30000 25000 20000 15000 10000 5000 0 Population Growth of Bacteria in Ideal Conditions Time (hours) 5

A 10-5 dilution is performed on a culture of bacteria in order to perform viable plate counts. From the dilution, *0.1 mL* of solution is plated on solid media, and 278 colony forming units grow on the plate.    How many bacteria are in a single mL of the original culture? Express your answer to two decimal places using scientific notation. In scientific notation 540 would be written as 5.40*10^2.  Since only 0.1 mL is put on the plate, this counts as an extra dilution!!! Any time less than 1 mL is transferred, a dilution is being performed. Any time more than 1 mL is transferred, a concentration is being performed. Include the trailing zero so there are two decimal places Canvas expects a single digit before the decimal point. 5.40*10^2 is how Canvas expects 540 to be formatted in scientific notation 54.00*10^1 would be marked wrong. 0.54*10^3 would be marked wrong. A 10-5 dilution is performed on a culture of bacteria in order to perform viable plate counts. From the…

For the state science fair, a student investigated the change in a yeast population over five days. The experimental design included the following. • The yeast were grown on a (5%)glucose (sugar) media in a closed, sterile petri dish for five days. • The petri dish was kept at a constant warm temperature (30°C) in an incubator. • The petri dish was observed under a microscope each day during the study, and the number of live cells in the same area of the petri dish was recorded. • Illustrations of observations were made each day of the investigation. Illustrations of Daily Observations of Growing Yeast Colonies :- Day 1 Day 2 Day 3 Day 4 Day 5 18 Cells 58 Cells 111 Cells 69 Cells 35 Cells

If the number of bacteria were to grow exponentially with a daily rate of r = 0.2612, how long would it take for the number of cases to double? Explain.

You can determine the Z-value for both organisms by calculating the temperature change required to reduce the D value by 1 log cycle. (Observations: Notice the difference in the two organisms. One has a steeper downward slope, but is offset higher. It is slightly more heat-tolerant, but slightly more susceptible to increases in temperature.) Question: Raw milk can be contaminated by several common pathogenic bacteria (i.e. Staphylococcus, M. tuberculosis) and therefore must be pasteurized. Your goal is to find the minimum temperature and time required to destroy these organisms. If you know the Z-values for staphylococcus and M. tuberculosis, do you have enough information to set the appropriate heating parameters?

If Microbe A and Microbe B have whole genome similarity of 68%, as determined by DNA-DNA hybridization, they should be considered the same species.

Assume that after washing your hands, you leave ten bacterial cells on a new bar of soap. You then decide to do a plate count of the soap after it was left in the soap dish for 24 hours. You dilute 1 g of the soap 1:106 and plate it on heterotrophic plate count agar. After 24 hours of incubation, there are 168 colonies. How many bacteria were on the soap? How did they get there?

A medium was inoculated with 5 * 106 cells/ml of Escherichiacoli cells. Following a 1-h lag, the population grewexponentially for 5 h, after which the population was 5.4 * 109cells/ml. Calculate g and k for this growth experiment.

Number of live cells (log) A B C D Time Which of the following statements is CORRECT regarding Figure 6.1 (above)? Cells are actively reproducing only during the stage represented by B. The population is increasing arithmetically during the stage represented by B. Cells are most susceptible to antibiotics during the stage represented by D. Cells are alive but not reproducing during the stage represented by A. No new cells are being produced during the stage represented by C.

A student is performing a bacterial growth curve experiment. At t= 0 hrs, he inoculated 50 mL of the favorable growth medium with 2x 10* bacterial cells. After 6 hrs, the bacterial population was around 450 CFU/50 mL bacteria. Calculate the growth constant "k" for the bacteria.