There are 90 million living bacterial cells (90,000,000) per ml in a flask, determine this using serial dilutions. There are only 3 test tubes available for you to do dilutions with. You must end up with less then 100 colonies on your plate. You must do at least one 100x dilution and one 10x dilution. Please describe all of your dilutions, how much liquid is being transferred in each dilution, how much liquid is put onto a plate, and how many colonies you see on a plate.
Answers
Answer:
Dilutions are useful in science when making solutions or growing an acceptable number of bacterial colonies to count. There are three formulas used to work microbiology dilution problems: finding individual dilutions, finding serial dilutions, and finding the number of organisms in the original sample.
Finding the individual dilution for each tube is essential for dilution problems.
To find a dilution of a single tube, use the formula: sample/(diluent + sample). The sample is the amount you are transferring into the tube, and the diluent is the liquid already in the tube. When you transfer 1 ml into 9 MLS, the formula would be 1/(1+9) = 1/10. This could also be written as 1:10.
For serial dilutions, multiply the individual dilutions together to get the final dilution.
After you have calculated the individual dilutions for each tube, multiply the dilutions when using serial dilutions. Serial dilutions are the culmination of some diluted tubes used to get smaller dilutions. When a sample diluted 1/100 is added to a sample diluted 1/10, the final dilution would be: (1/100) x (1/10) = 1/1000.