diluted a bacterial culture a million-fold. you then plated out 0.1 mL of dilution and after incubation, 45 colonies appeared on the plate. How many bacteria/mL were in the original undiluted culture
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you diluted a bacterial culture a million-fold. you then plated out 0.1 mL of dilution and after incubation, 45 colonies appeared on the plate. How many bacteria/mL were in the original undiluted culture?
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- A 2x10-6 dilution of your bacterial culture yielded 10 colonies. What was the cell density (incells/ml) of your bacterial culture?If 1.0 mL of a 1:1000 dilution produces 200 colonies on a culture plate, how many bacteria were present per mL in the original (undiluted) sample? 200,000 20,000 2,000 200If you counted 300 colonies on a plate that had a 10-5 dilution of bacteria culture, how many colonies might you expect on a plate that had a 10-6 dilution of the same bacterial culture?
- If you started with a bacterial concentration of 2,000,000 bacteria/ml and wanted to plate out 40 bacteria what would be the dilution scheme of using 4 dilutionsIn a serial dilution, you plate 1 ml of a 1/1000 dilution of a bacterial culture and find 25 colonies the next day. What was the concentration of cells in the original culture? A) 25 cells/ml B) 0.000025 cells/ml C) 25,000 cells/ml D) 26 cells/ml E) 0.025 cells/mlYou make a 1:100 dilution of your culture and plated 0.1 ml of this sample on a Nutrient agar plate. After incubation, you counted 50 colonies on the plate. How many organisms were in the original culture?
- Did each handwashing treatment result in similar types of organisms growing on the plates? (look at the colonies and gram types) Explain why or why not?You have spread 0.1ml of a 1x10-8 diluted bacterial culture sample on a Petridish and counted35 colonies. What was the cell density of your original culture (in cells/ml)? How many cellsdid you have in 100ml of that culture? DON’T FORGET TO ROUND!You have 2 mL of bacterial culture. How would you make a 10^-2 dilution using the entire culture volume
- When analyzing your results after performing a serial dilution, you obtain an average of 40 colonies on your 1 x 106 plate. How many cells were in the original sample?How do we reconcile the number of colonies in the plates to the actual number of bacteria in the original sample? Count Plate MethodYou place 1 ml of a bacterial broth culture into bottle A containing 99 ml of sterile water and mix. You take 1 ml from bottle A and transfer it to bottle B, which contains 99 ml of sterile water. What is the dilution of the bacterial culture in bottle B?