Lab Report 2 - General Microbiology-merged

Why do variations in generation time exist:a. Among different species of microorganisms?b. Within a single microbial species?

A species of bacteria has a doubling time of 24 hours. After incubating the initial population for one week, the final population was 6,400 cells. What was the initial population of that bacteria? Show all work. Equations: Nt = No x 2n Final concentration = (initial concentration)/(total dilution factor)   Total dilution factor = (individual dilution factor)# of serial dilutions

Population calculation A culture of bacteria is started with an initial input of 250 cells. After 20 generations, how many bacteria would be present in the culture?

Give an example of an industrial/clinical setting where quantifying viable bacteria would be useful. How would you prepare a series of dilutions to get a final dilution of 10–10? Outline each step.

You sample cole slaw for bacteria soon after purchase, and after it has been left out on the kitchen counter for 6 hours (room temperature), and after 12 hours (at room temperature).    From the data below, CALCULATE  the generation time of the bacteria in this sample (at room temperature) – that is, the time it takes for the bacterial population to double in number. Soon after purchase:                                          4.0 x 103 bacteria per mlAt 6  hours at Room Temperature:                     1.9 x 105 bacteria per ml ( = 192 x 103 bacteria per ml)At 12 hours at Room Temperature:                    1.2 x 107 bacteria per ml  ( = 12,300 x 103 bacteria per ml)  What do you calculate the generation time to be?                                                 (generation time is the time needed for the population to double in size )                                  Hint:  What is double the initial population?                                                                Hint:…

Define what is a minimal medium and the nature of its components.

Researchers are designing several experiments to test the ability of Salmonella bacteria to develop antibiotic resistance. A culture of Salmonella bacteria is exposed to the same concentrations (200 mg/L) of an antibiotic for four days. The table shows the number of isolated resistant bacteria over a four-day period. Which of the following statements best explains these results? Day Number of Resistant Bacteria in the Culture 1 5 2 59 3 677 4 32,456 The bacteria were not affected by the antibiotic. After being exposed to the antibiotic, the bacteria altered the antibiotic. A new species of bacteria emerged after the antibiotics were introduced. Random mutations led some bacteria to be resistant and, over time, they increased in the population.

Which of the following types of data produce curves similar in shape to the graph? Select all that apply 1.Bacterial growth in a culture 2.A normal distribution of height in a population of students 3.Exponential population growth 4.Haemoglobin binding of oxygen 5.Log transformations of drug dose curves 6.Osmotic fragility of red blood cells 7.A standard curve for an enyme assay

As a technologist in the brewing industry, your job is to research and develop ways to improve the yield and quality of brewed beverages. You are responsible for growing and maintaining the particular strain of microorganism that is used in the fermentation of beverages. Name 2 environmental factors that would affect the growth of this organism and which you will need to optimize for abundant growth of your organism.

what is k and r for each condition?  K (carrying capacity): can be estimated by finding the point where the growth curve levels off. Take the average of this data point and all data collected beyond this point to estimate k (note: if the bacteria population is still growing, you can just take the last value of data for k.  r: choose any two points at the log phase of growth. Then use the r formula.  Just choose two waste conditions for r and k calculation so I can get the idea of how to do this, thanks.

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 2 Time (hours) 3

You are a technician working in a microbiology lab. You grow two bacteria cultures, Bug A and Bug B, for two purposes: You want to harvest lactic acid for sports drinks from Bug A. You want to harvest antibiotics from Bug B for the pharmaceutical industry.  Describe how you would maintain the two cultures, how you might manage their nutrient supply and waste products in order to induce them to produce the desired products. Which stage of the growth curve would you try to keep them in?

An inoculum of 106 bacterial cells was introduced into a flask of culture medium and growth monitored. No change was seen for 18 minutes (the lag phase), then growth occurred rapidly. After a further 87 minutes, the population had increased to 5.08 × 107 cells. What is the doubling time of the culture? Show your solution. (The 87-minute period is after the lag phase.)

List and describe the phases of the growth curve of a population of bacteria.  Explain how a decrease in one environmental factor (choose oxygen, temperature, OR pH for your explanation) might affect the growth curve of that bacterial population.

Solve the following problem: 34,000 bacteria/l have been measured 4 hours after inoculating a medium. After 24 hours, the number of bacteria increased to 5.2x10^6/l. Assuming that the lag phase is negligible, calculate: The specific speed of growth. The number of bacteria that were inoculated.

make a graph out of this t = time of growth of bacteria in mins y = number of bacteria

A bacterial culture contains 500 organisms / mL in the exponential growth phase at 8 am in the morning. If you consider a generation time of 20 minutes, the total number of organisms / mL (round off to the nearest integer) after three hours (i.e. at 11 am in the morning) will be

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.

Are you able to identify the lag, log, stationary and death phase in using these growth curves?Are you able to calculate the generation time for this microbe under the two conditions?

Answer the attached picture below briefly and concisely.

A microbiologist inoculates a growth medium with 100 bacterial cells/ml. If the generation time of the species is 1 hour, and the microbes are in the exponential (log) phase of growth, how many hours require for the culture to surpass 10,000 cells/ml, if the culture is checked once each hour? O 1) 2 hours O 2) 7 hours O 3) 3 hours O 4) 10 hours O 5) 24 hours

What is the role of glucose, which is added to a minimal medium? Use the appropriate vocabulary

Which of the following include the correct order of phases of a typical bacterial growth curve? log, lag, stationary, decline/death lag, log, stationary/decline, death lag, log, stationary, decline/death log, lag, decline/stationary, death

Use the data below to calculate the colony forming units per mL (CFU/mL) from a sample of bacteria after growing the sample in an incubator for 2 hours. Culture density (CFU/mL) = Time 1 hour 2 hours 1x 10-¹ 1 x 10-² 1x 10-³ 1x 104 number of colonies (dilution) x (volume plated, in mL) Dilution (before plating) Volume spread on plate (replicate plates) 1x 10-1 1x 10-² 1x 10-³ 1 x 104 0.1 mL 0.1 mL 0.1 mL 0.1 mL Number of colonies observed 0.1 mL 0.1 mL 0.1 mL 0.1 mL TNTC 660 101 8 TNTC 220 15 3 TNTC 783 115 7 TNTC 180 9 7

Suppose that you were tasked with 4 cultures of a specific Bacteria Species in Luria Broth medium: (1) culture A – cells are in lag phase; (2) culture B – cell in log phase; (3) culture C – cells in stationary phase; and culture D – cells in decline phase. Imagine that you observe the growth rates of each culture in a fresh sterilized LB medium. Now, plot the outcome growth curves of cultures A, B, C and D in a single graph.

Describe in full the technique of density gradient centrifugation?

describe the molecular switches involved in microbial stationary growth phase. give one research article link

Describe the following phases of the bacterial growth curve and draw them out:a.    Lag phaseb.    Logarithmic phasec.    Stationary phased.    Decline/death phase