Exactly one-tenth of your cells are now in a new tube with a final volume of 10 ml.Plus, get practice tests, quizzes, and personalized coaching to help you.
Advantage And Disadvantage Of The Serial Dilution Agar Plate Procedure Serial Dilution OfFortunately, through precise serial dilution of a sample, it is possible to get down to a number that is much easier to work with.What happens when you need to know how many individual bacterial cells are contaminating a food, living in an environmental sample, or growing in a culture tube You need some method for counting the bacteria accurately.
But, it is not uncommon for a liquid culture of bacteria to have a billion cells in every milliliter of media. That means that every teaspoon of liquid could potentially have 5 billion bacteria in it. Even if you counted one bacteria every second, it would take you over 150 years to get to 5 billion Obviously, this is not a viable option. Ideally, you want to only have to count between 30 and 300 bacteria, a range of numbers that takes only at most a few minutes to count. But, how do we get there Serial Dilution The answer is through dilution. If you simply pull out a smaller, exact quantity of culture liquid, you could count those bacteria and, based on how much you pulled out of the total, you can determine how many bacteria are in your original sample. Sounds easy, right But first, one more analogy: you have billions of bacterial cells and need to get down to 30 to 300. In order to do that, you would have to dilute your sample about 10 million-fold. To do this, you would need to take about 15 milliliters of your sample, about 3 teaspoons, and dilute it into your swimming pool I doubt this is a viable option, especially if youre working in a cramped lab space. Advantage And Disadvantage Of The Serial Dilution Agar Plate Procedure Series Of SequentialA serial dilution is a series of sequential dilutions used to reduce a dense culture of cells to a more usable concentration. Each dilution will reduce the concentration of bacteria by a specific amount. So, by calculating the total dilution over the entire series, it is possible to know how many bacteria you started with. The best way to fully grasp serial dilutions is to try out the procedure yourself. How to Perform a Serial Dilution Im going to walk you through an example serial dilution using the easiest method, but, once you grasp the concept, you can change the actual numbers to whatever works best for you and do it the same way. To start, we need 10 milliliters (10 ml) of your original bacterial culture (labeled OBC). Your liquid could be growth media, saline, sterile water, or any other appropriate liquid. If your cells settle to the bottom, and you remove liquid without swirling, you run the risk of not getting enough cells, invalidating your final count. Once swirled, carefully transfer exactly 1 ml from your OBC Tube to Tube 1.
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