#4. You have been given a tube of E. coli. You are asked to make 1 mL total volu
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#4. You have been given a tube of E. coli. You are asked to make 1 mL total volume of 10 dilution of the bacterial culture. Explain how you would do this. Show all necessary calculations. #5 You have bacteria at a concentration of 5 x 108 CFU/mL. You spread 1 mL of this sample on an agar plate to obtain isolated colonies. How many colonies do you expect to find the next day after incubation at 37°C? Can you count these colonies? Can you use this plate for determining concentration? #6. You have bacteria at a concentration of 1 x 103 CFU/mL (in real life-you don't know this, but we are just working on math skills here). You transfer 1 mL of this sample into 9 mL of water and then spread 1 mL on a plate of agar. How many colonies do you expect to find the next day after incubation at 37°C? Can you count these colonies? Can you use this plate for determining concentration? #7 You take 0.05 mL of a culture of bacteria at a concentration of 4 x 10' CFU/mL, and add 4.95 mL of water to it. What is the dilution that you have performed? What is the concentration of bacteria (CFU/mL) in the diluted culture? #8. You have diluted a sample by 1000 fold ( 1 /1000) and plated 1 mL on an agar plate. You observe 55 colonies. What was the concentration of the original sample in CFU/mL? l sample has a concentration of 3 #9. A bacterial x10 CFU/mL. You make serial dilutions of 10 followed by 102 and 101 dilutions. You finally plate 1 mL of the last dilution on an agar plate and incubate it at 37 What is the total dilution? How many colonies do you expect to see on the plate? Total dilution: # of colonies expected on plate: #10. This time, you see 10 times fewer colonies than you had expected to see. What could have gone wrong? How will you fix this problemExplanation / Answer
Answer=4]
There is a tube of E.coli
preparation of 1mL total volume of 10-1dilution of the bacterial culture is
10-1dilution means 1/10 dilution means 1 ml of bacterial culture & add 99 ml of broth.(1:10)
but we have to make total 1 mL volume
therefore we have to mix 0.1 ml i.e.100 ul E.coli culture & 0.99 ml i.e.990ul of broth for the preparation of 10^-1 dilution
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