So here s the general rule: in order to be valid, the plate that you scale up should contain between 25 and 250 CFUs.
Pull out 1 mL of this latest mixture, and you ll have 1/100th of 1/100th, which is multiplying the fractions together 1/10,000th.
Assuming you didn t stop to eat or sleep.
Its nasty he said, just as his second sister came.You should practice this until it is second nature.I need a hint : 11 of the little bags would go into one big bag I think I have the answer: about 35 11 about 400.So, when we count the caffeine molecules in a cup of wimpy coffee, we know we got 1/50th of what was in a cup of the original brew - or in other words, there was 50 times as much in a cup of the original.
There s not enough tupperware here for all that food.
Well, dilution and plating is quick and easy compared to the pain of starting your experiment all over again.
OK, then go on to the next page Now that you are very comfortable with dilution factors what happens if you dilute and then dilute again.
We ll talk about a specific method serial dilution, plating, counting, and scaling up, but I want to make it clear at the outset that the problem of counting huge numbers of things is not at all unique to counting bacteria.
For example, you could put one cup of cold press coffee into a pot and add 9 cups of water.Start with a,000 dilution someone else has made.But remember that diluting and sampling is bascially a random process, and imagine the havoc caused by one extra CFU ending up in your pipette - suddenly you estimate the population as 60,000 rather than 50,000, and you re off.So let s put this all together.When we said the diluted coffee was 1/10th as strong as the original that was a dilution factor.OK, there might be a few other morals: futurama jurassic bark full episode Serial dilution means you do a series of dilutions, where each dilution gets you closer to your goal.She quickly caught on to the soup-dilution scheme, found the leftover stock, dumped it over the prince s head, and sent the girlfriend packing.I didn t think of that Well, we don t need to mix up all 100 liters.At dinner the prince s girlfriend slurped down the watery soup like a trooper.I think I have the answer: 0,000,000.