 So, viruses are surprisingly diverse for being as simple as they are. I'm going to write down what a virus is just so you have like a definition. It's basically some sort of genetic material inside a protein coat. Okay, that's it. A protein coat, so imagine like a protein capsule and inside is genetic material. I say genetic material because that can be DNA. That's what our genetic material is, but there are RNA viruses. And so the genetic material in the virus could be RNA as well. When we think, okay, that is a very simple thing. In fact, viruses, it is generally agreed that they aren't even alive. They literally cannot function at all unless they infect someone else's cell. They aren't considered cellular, and the cell as we know is the first level of organization where we have the qualities of, or the characteristics of life. This is a topic of hot debate. It's a topic of hot debate in my very own household, but I still stick with, dude, these things aren't even alive, but they're not alive, but they're like wildly diverse. I stole this picture right here. This is a picture of a bunch of different virus particles. And I found the virus resource of ever. Check this thing out. You're just not going to believe. If you need to be convinced that viruses are profoundly diverse, go check out this website. Of course, they have a lot of information about the SARS-CoV-2 virus. It's a type of coronavirus and we'll look at that structure carefully. But look, these are all categories like different kinds of virus groups. And you can go and look up and learn about all of them. And look, not all of them infect humans. We have plant viruses. And look at this virus is a virus that infects the Archaeans. Remember, the Archaeans and the bacteria were two types of prokaryotes, two groups of prokaryotes. They have their own category of viruses that infect them. You can look at all these different categories like, I don't even know where to start, but you can take a different class on microbiology or virology and enjoy learning about these things. Like, dude, it's ridiculous. And it's also ridiculous how many viruses are out there. The only care that they are protein coats with genetic material inside. Let's take a closer look at the coronavirus. So let's be really careful about our language here. It's the SARS-CoV-2 virus. That's the name of the virus that causes COVID-19. So COVID-19 is the disease that you get if you get infected with the SARS-CoV-2 virus. It's super easy to talk about the COVID-19 virus, but I'm going to attempt. I will not be perfect, I guarantee, but I will attempt to make sure that I'm using the proper language. So let's just write that down. This is SARS-CoV, and that is a little O, CoV-2, I think that's how it's written. I'll make sure that I've got that correct. I'm not sure where the dash goes, I can't remember. You know how easy it would be to look to make sure I know where I did it perfectly because the dash goes right there. Okay, so this is the virus, good Lord, virus, and it causes COVID-19, and this is the disease. Okay, so take a look at the COVID- I mean, the SARS-CoV-2 virus particle. Here it is. And you can see coronaviruses all have these spike proteins. Those spike proteins are the characteristic that's particularly unique about coronaviruses, and they all have them. They're just proteins that help the virus function to get into the cells that it's infecting. You'll notice that the SARS-CoV-2 virus has an RNA genome. So its genetic material is RNA, not DNA. That's significant. You'll notice that it has a little envelope. The genome is actually inside here. I'm just going to make sure that you can see that. All that stuff inside the protein coat is your RNA. Super simple. That's it. Protein and genetic material, that's the anatomy. Floats around, doesn't do do do, unless it can get into a cell. Getting into a cell, I translate that from structure, what you're seeing right here, to function. So let's take a look at how viruses in general and the SARS-CoV-2 virus, in particular, how they get into the cell and replicate themselves.