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?

Aliivibrio fischeri is a marine bacterium that uses quorum sensing to regulate bioluminescence. These bacteria will only bioluminesce when the population is above a certain density. Why would it be advantageous to bioluminesce only when the population is large?

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

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

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.

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?

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:…

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.

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?

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.

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.

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.

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.

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

Provide an example of an organism within each of the four main nutritional categories of microbes and describe how each obtains its essential nutrients. Provide evidence in support of or refuting the following statement: Microbial life can exist in the complete absence of both sunlight or organic nutrients. Polymerase chain reaction (PCR) is a technology that requires high temperatures to reproduce DNA fragments. Explain why the discovery of thermophilic archaea and their associated DNA polymerases was critical to the success of this technique. Summarize how the electron transport chain functions to produce ATP in a bacterial cell versus eukaryotic cell. Explain whether or not the term chemiosmosis accurately illustrates this process.

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

Log Nt = Log N0 – t/D.   D is the time required for a log kill. A single dose of mouthwash is added to a bacterial culture with 10 million cells/mL and, after 30 minutes, one hundred thousand viable cells/mL remain. How many would survive at the end of 1.5 hours? Based on the equation, can you ever totally decimate the population? In a practical sense, when would you assume that all the cells are dead?

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

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

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

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

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?

You want to produce a biological agent to kill bacteria that cause disease. Which organism you will isolate? Which product do you have to produce? Which organism How can you use your biotechnological knowledge to produce it in high amount? Please answer asap

A large oil spill in the Pacific Ocean is threatening marine life. Scientists charged with cleaning up the spill believe bioremediation is the best option, but they are not sure what type of bacterial species to use in the bioremediation process. To help them in their decision, they have listed the nutritional modes of each species. Given your knowledge of the different nutritional modes of bacteria, which nutritional mode would be most beneficial in bioremediation of the oil spill? Chemophototroph Extremotroph Photoautotroph Chemoheterotroph

If it takes 2 hours for a population of bacteria to grow from 100 cells to 1600 cells, what is the generation time of this bacterial species?   15 minutes 20 minutes 30 minutes 40 minutes