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Microbiology

Learn the toughest concepts covered in Microbiology with step-by-step video tutorials and practice problems by world-class tutors.

10. Dynamics of Microbial Growth

Introduction to Cultivating Microbial Growth

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Introduction to Cultivating Microbial Growth

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in this video, we're going to begin our introduction to cultivating microbial growth. And so studying microorganisms in a laboratory requires growing the microorganisms on culture medium. And so culture medium is sometimes referred to as just media is either going to be a solid or a liquid preparation of nutrients that are used to grow microorganisms. Now a solid preparation of these nutrients is referred to as auger and a liquid preparation of the nutrients is referred to as a broth. And recall from our previous lesson videos that a pure culture refers to a population of cells that started from just a single colony viable cells. And so if we take a look at our image down below notice on the left hand side over here, we are showing you an image of auger which is a solid growth medium found inside of one of these Petri dishes here. And so this is a Petri dish and the red uh color that you see represents the culture media uh in a solid form that we refer to as anger. And you can see that the microorganisms are capable of growing on top of this solid culture media. And so the culture media is pretty much providing the nutrients and so it acts as food. And so the bacteria are able to grow on this auger medium which is providing the nutrients and the food that it needs. Then over here on the right hand side, notice that we're showing you a liquid broth, which is really just a liquid growth media and notice that the container is going to be different in order to store a liquid. And all of this red that you see here is really just the liquid culture media, which again is going to act as a nutrients and a food source for these organisms. And the organisms are going to be able to grow inside of the liquid broth. And so we're able to grow microorganisms on solid auger media or liquid broth media. Now, it is also important to note here that when cultivating microbes, it's extremely important to avoid contamination by using what's known as a septic technique. And so aseptic technique is a specific series of techniques that are going to be very important when you're, when you're working with microbes, cultivating microbes in the lab. And so aseptic technique can be defined as a standard practice in the lab and medical procedures that ultimately prevents contamination. And really, that's the main goal behind aseptic technique, is that you perform very careful techniques to make sure that your um culture media does not get contaminated from some unwanted microorganisms. You only want to be growing the microorganisms of interest. And so aseptic technique helps to ensure that. And so this year concludes our brief introduction to cultivating microbial growth. And we'll be able to get some practice applying these concepts and learn more as we move forward in our course. So I'll see you all in our next video.
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Map of Techniques for Cultivating Microbes

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in this video, we're going to introduce our map of the lesson on techniques for cultivating microbes, which is down below right here. And so this image represents a map or an outline of our lesson moving forward. And as always, we're going to be following the map by following the left most branches first and then zooming out and covering the other branches in this order that you see right here. And so what's important to note about the techniques for cultivating microbes is that whenever you are cultivating microbes, it's really important to make sure that you're performing aseptic technique, which recall is just a specific series of techniques that helps to prevent contamination. And it could include things such as using a Bunsen burner to help prevent contamination or using gloves to help prevent contamination as well. And so, aseptic technique is something that's going to be important for all of these other techniques down below as well. Now, over here on the far left, what we're showing you are types of culture media and we'll talk more about these moving forward in our course. But this includes things like slants, deeps and Petri dishes. And then after we cover the types of culture media will move on to plating methods and we'll talk about specific plating methods such as the street plate method, the poor plate method and the spread plate method. And then last but not least we'll move on to counting cells. And so there are direct cell counts such as microscopic counts and sell counters. And there are also viable cell counts like plate counts, membrane filtration and most probable number or M. P. N. And then of course there is measuring biomass using a spectral tata motor or by direct weight. And so we'll be able to talk more about all of these different techniques as we move forward in our course. And again this is really just an outline of our lesson. So we'll start off by talking about the types of culture, media, and so I'll see you all in that lesson video.
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