Assume that you counted 67 plaques on a bacterial plate where 0.1ml of a 10-5 dilution of phage was added to bacterial culture. What is the initial concentration of the undiluted phage? Show your calculations and give your answer in pfu/ml (pfu = plaque-forming units)

You perform the Methyl-Red(MR)& Voges-Proskauer(VP)test and gather the followingresults: (Uploaded picture). VP test result is on the left, MR test result is on the right. A) Please interpret these results. B) Your fellow researcher and yourself are sure your bacterial sample is either E. coli or P. vulargis. Basedupon the work we have done in lab which methods will help you determine which bacteria it is? Please explain why, the results you would want to observe and provide analysis of those results.

You use a spectrophometer and estimate the concentration of bacteria in a urine sample to be 4.6 x 10^5 cells/ml. Assuming you will plate 0.1ml of your samples, to what factor should you dilute your sample to get a countable number of colonies? Rearrange Original Cell Density formula to solve.

Complete the colony morphology for the colonies pictured above: 1.  Form - 2.  Elevation - 3.  Margin - 4.  Surface - 5.  Chromogenesis -

If coliform bacteria are native to human colons, why the big concern over coliform contamination?

You perform a Minimum Inhibitory Concentration (MIC) assay on a bacterium that you have isolated from a patient, with the results shown below (white material = bacterial growth). Which of the following is NOT a correct statement about these results? Erythromycin Gentamicin Concentration (ug/ml) 300 None of the other four answers (All statements are true 200 A lower concentration of erythromycin than gentamicin will inhibit growth of this bacterium The MIC for gentamicin was not determined in this test The MIC for erythromycin was 50ug/ml The bacterium was resistant to gentamicin at all concentrations tested

Fifteen bacterial colonies growing on a complete medium (that means that they have all of nutrients that they need supplied in the dish, and they don't actually need to synthesize these compounds to survive) are transferred to minimal medium. Twelve of the colonies grow on minimal medium. Three colonies do not grow on minimal medium. But, if these three colonies are put on a plate that has minimal medium supplemented with the amino acid serine (min + Ser), they all What does this suggest about the three bacterial colonies (pick all that apply)? grow. They lack the ability to synthesize their own serine. O They are probably wild-type. They probably have a mutation that causes them to lack a certain protein. They probably have a mutation that causes them to be unable to perform translation. O They probably have a mutation that causes them to be unable to perform transcription. O They are able to synthesize everything that they need to grow except for serine.

Citing the data from your results table tell which antibiotic is the most effective against this type of bacterium. Citing the data from the results table tell which antibiotic is the least effective against this type of bacterium. Explain how you determined the level of effectiveness. Describe what the Petri dish looked like. Hint(the most effective antibiotic has a larger clear area around the antibiotic disk. The least effective antibiotic has a smaller clear area around the antibiotic disk.

You perform the Methyl-Red(MR)& Voges-Proskauer(VP) test and gather the following results: (Uploaded picture). VP test result is on the left, MR test result is on the right. Please interpret these results and answer this: Your fellow researcher and yourself are sure your bacterial sample is either E. coli or P. vulargis. Basedupon the work we have done in lab which methods will help you determine which bacteria it is? Please explain why, the results you would want to observe and provide analysis of those results.

Write a paragraph for when you once have Neisseria gonorrhoea bacteria in its pure form, what methods can you use to confirm the identity of this bacterium as N. gonorrhoeae? Mention what is the principle of those methods.