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

9. Microscopes

Introduction to Microscopes


Introduction to Microscopes

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in this video, we're going to begin our introduction to microscopes. And so, as you guys already know, microbes are simply way too small for our bare eyes to see on their own. And so our eyes require the aid of microscopes in order to visualize those incredibly small microbes. And so a microscope, as its name implies, is going to be an optical scope or instrument that is used to visualize microscopically small objects such as cells, for example. And so recall that the root micro is a route that means small. Now moving forward. In our course, we're going to be talking about two main types, or two main groups of microscopes that are commonly used. And so the first main type is going to be the light microscopes, which as its name implies, is going to be using visible light in order to magnify small objects and make those small objects appear larger. Now the second type of microscope that we're going to talk about moving forward are the electron microscopes, which as their name implies, is going to be using electrons for an even higher magnification of even smaller objects. And so the electron microscope is going to be a much more powerful tool and is therefore, we're going to be a lot more complex. And it's going to be a lot more expensive than the light microscopes themselves. And once again, as we move forward, we're going to be talking about different types of light microscopes and different types of electron microscopes. But for now, let's take a look at this image that we have down below, which is showing you the ranges of the human eye, light microscopes and electron microscopes as well. And so notice that in this image it's showing you a bunch of objects across the top here. And uh these objects are arranged in in terms of their size. And so notice that the further to the left are the really, really small objects. Uh And as you go to the right are the larger objects. And so this image helps to put things in perspective a little bit. And so notice on the far right, the largest object that we're showing is actually a human. And uh notice that on the left, the smallest object that we're showing here is the atom or atoms. Now notice that down below we have this scale that's showing you the ranges in terms of their sizes. So it goes from 10 m over here to one m to one centimeter one millimeter and so on. And the smallest that we have down here is a unit called Angstrom Xyz one Angstrom is a really, really small unit. And so notice that we have here. The ranges of the human eye. Uh this green region represents the human eye. And so are our eyes are able to see really, really large things. But there's a limit to how small we can see with our bare eyes. And notice that we are able to see objects such as ants. And some cells were able to see such as frog eggs are quite large, but most plant and animal cells and most bacteria and archaea are simply way too small and outside of the range of our eyes to be able to see. And so in order for scientists to be able to visualize cells and smaller objects, we need to use microscopes. And once again, there are two main types of microscopes that we'll talk about moving forward. There's the range of the light microscopes are right here uh in this blue range. And so you can see that the light microscopes are can be used to visualize most bacteria and archaea and most animal cells, but they're not usually powerful enough to visualize viruses in most cases. And so if we want to visualize viruses which are smaller than most bacteria, archaea and eukaryotic cells, we need to use a more powerful type of microscope called the electron microscope. And so notice that the electron microscopes range allows for the visualization of much smaller objects, including most viruses. And even some uh smaller molecules like proteins and lipids, or macro molecules like proteins and lipids and small molecules like water molecules and things of that nature. And even some atoms as well. And so really this is just a cool image that helps to put things in perspective to show you how these uh you know, different objects compared to each other in terms of their size. Now, a few things to note here that's going to be important for you as you move forward is notice that most plant and animal cells, which are eukaryotic cells that contain a nucleus are going to be larger than most bacteria. And archaea which are pro carry attic pro carry, attic cells tend to be smaller than eukaryotic cells and that's something that will touch more on as we move forward in our course. Another thing to note here is that viruses are much smaller than even bacterial cells, even pro periodic cells. And so viruses are really, really small and usually viruses can only be visualized with electron microscopes. And that's an idea that will also emphasize more as we move forward as well. But for now, this year concludes our brief introduction to microscopes. And once again we'll be able to learn a lot more about these different types of microscopes moving forward. So I'll see you all in our next video

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