 Hey everybody! Super exciting lecture today because we finally get to talk about something that is alive. Before we start our lecture talking about the cell, I want to take you through a little slideshow of some different kinds of cells. Inside humans, now if you haven't figured it out already, I definitely have a human bias. I find human anatomy and physiology super interesting and I definitely know more about humans than any other critters out there, but this class as a general biology class, we have to prepare you with content to get you into anatomy and physiology but we also have to take some time to appreciate all life and the diversity of life. That's one of the coolest things about this class. So let's just start with a little survey of some cool-looking cells. This first slide has two different kinds of cells. They have a lot in common, these two cells, but if you look at them, you're like, dude, what are these even? Both cells, and they are. The one on the left is a protist. It's a animal-like single-celled organism. One single cell, that's its whole being, and we'll spend some time talking about protists. They're kind of a weird group of critters. The cell next to it is a neuron. That's like a brain cell in humans or in lots of animals have neurons. It's kind of an advanced nervous system cell that plays a role in communication. You can see how that cell has the central cell body, like we will see all cells have, but then it has these really long extensions of basically of cell guts, like cell membrane reaches way out and it has all the cytoplasm and cell guts that reach way out and communicate with other cells. One of the things that we will see is that cells really specialize for their needs. So different kinds of cells look the way they do. They have the structures that they have because those structures enable various functions. This is a single-celled fungus. It's a yeast. Yeast, I mean, anywhere we go, we got to appreciate our yeast. Yeast are provided gases to make rising breads. So if you like bread, then yeast are your friends and of course yeast pee is alcohol. So in the absence of oxygen yeast make alcohol and lots of humans like to ingest yeast pee and have a good time. We'll talk more about that at a later date for sure. Here are some red blood cells. These are one of the smallest cells in human bodies. They look kind of like little doughnuts and they fill our bloodstream. They carry oxygen and carbon dioxide around oxygen to your cells. So they have fuel, carbon dioxide away from your cells because carbon dioxide is garbage. Garbage, that's why we breathe it out. Thank you, red blood cells. White blood cells. They don't carry oxygen around. They use the oxygen. They produce carbon dioxide, but they are our immune system. So you've probably been hearing a lot about white blood cells and T cells and different immune cells in our bodies. And this is one of them. The other thing that I think is really cool is to look at this. You might look at this and be like, dude, what is that white blood cell sitting on? It looks to me. I'm like, oh my gosh, it's a parasite worm that it's sitting on and it isn't. It's sitting on the fibers that form blood clots. So this little white blood cell got caught up in a blood clot, the fibrin proteins in a blood clot. Here is a bacterium. Now this type of bacteria, if you look really closely, each one, they're like these little rod-shaped cells. Bacteria are much smaller than all the other cells that we've looked at so far and we'll talk about those guys. But I just think, I don't know, I got a little enchanted with the person who went through and colored all these micrographs because they are super pretty. But they just kind of, again, show you the diversity of what we can see out there. We've seen Henrietta Lacks's cells before. Remember these came from her cervix when they were diagnosing her with cervical cancer, took her cells, didn't ask, and continue still, are using her cells. And I don't think they've even yet, maybe they finally have compensated her family. But you can see some of the qualities of cells that are common to all these guys. You can see that big red nucleus and we'll talk about that guy at length. I could spend all day looking at these guys. Here's another protist, a single-celled organism, and these guys have stalks. And I learned when I was finding that picture going, oh my god, that's so cool. I learned that they have a that little stalk has the fastest muscle proteins. I don't know. I'm sure they don't call the muscle, but mover, mechanical movement proteins known that we know of. And there's a video, I'll try to link it somewhere so that you guys can check this out, but there's a video that they took of this guy where just all of a sudden like one of them will like contract and like run away. And then they, their little stalks come back up again, and then they'll contract really really fast. And you can see how how fast it happens, but that's one-cell. That's one-cell with some sort of cellular appendage that has this phenomenal function. I don't know if you can see it down here in this corner. That it almost looks coiled like it like it coils up to contract and pull that little head cell thing back down. This is a filamentous green algae. So this is a multi-cellular organism, but I just was again enchanted by the colors and how like organized and nicely structured these cells are. Each one of these boxes is a cell and it's filled with all the cell parts that we have seen and we will see in this whole lecture. Here are a couple more protists. This is a really interesting series here because these protists, you can see that fur that's all over them. They're like little hairy protists and those are structures, cilia, designed for movement. So that's how these guys move around. And I believe the guy with the two strings of cool hair, I think that guy is about to eat the furry one with all the hair. So there's actually a really cool series of pictures where you can see the one cell ingesting the other one. We'll talk a lot about energy and why everything needs to eat. So of course, of course, there are white guys involved in our conversation and I need to say this out loud. We're gonna talk about the cell theory and I'm gonna give you some facts about the cell theory. These guys came up with cell theory in the 1800s. I believe they're both German fellows. They were friends. I think they were botanists, whatever. We see a lot in any time I go and try to look up some history of science because it is interesting to think about the humans who discovered these things and think about them working together and the process of science. It is really interesting. But we see some patterns and the patterns are that you needed to have a penis and you needed to have not very much melanin in your skin. And those were the two rules to participate in science. Now those were the rules to participate in science, the science that we know in our society. And I think it's really important to keep in mind that that's where our information is coming from and that's who got to participate. I would like to think that we must change that. We must have diverse minds. We must have diverse perspectives. When learning, especially now, like the stakes are kind of high, we have lots to learn. But when I show you some of these historical humans, I definitely want to be sure you know that it was a very exclusive time in science. And I would argue an exclusive time in history as well. So the historical information that we get is determined by people who had penises and white skin. Okay, so let's talk a little bit about the concepts, the ideas that these guys came up with. And just take a second to think about they had access to microscopes, but they like this was kind of amazing for them to figure out that basically everything is made out of cells. Okay, so let's go. Let's see. I'm gonna close that down. I'm gonna go here. We want to do this. Come on now. Hold, give me a second. Okay. It's, I hate it when this does this. Okay, did that work? Okay, I'm gonna push pause and I'll be right back. Well, I think that worked. I paused it for a really long time and you didn't know, except that now I told you which why would I tell you? Okay, let's make a list of the cell theory tenets. There's three that the fellows we just looked at came up with and three more that got added after over some time. I would never ask you about their names or even the timing, like the historical information is not something that I'm gonna hang on to. I just think it's really interesting to have context and perspective. Okay, so cell theory. This is what the fellows came up with. Number one, I already said this, the cell is the fundamental unit of life. Do you feel like, dude, yes, we already know that. Okay, we don't need to spend any more time on that. We've labeled that and named that all along in the class. All, and this is interesting. This is kind of a chicken egg thing. All critters, all living things are made of one or more cells. Okay, this is where we have a virus debate in our future because the case is made that viruses do not have a cell membrane. Therefore, aren't cellular. So in order to be alive, you have to have a cell and then these guys, though the fellows came up with all cells come from other cells. This was kind of a shocking revelation that cells didn't just spontaneously arise out of like rat heaps or garbage dumps or anything like that. They actually had to come from existing cells. Those were our original tenants and then we added some more and I'll go ahead and throw these in a different color. They are basically all cells. I'm gonna not write all cells because I'm gonna run out of room here. All cells have the same chemical composition and dude, this is the part that I think is so cool. We're all, we're made of the same stuff. We've learned the building blocks. Those building blocks make up all cells. All cells have, use energy through metabolic processes and the metabolic processes are conserved. We see the same general processes in all critters using energy and producing waste products. And then the last one we have is that all cells have DNA and they pass it on to their daughter cells. In a world where the penis was sort of required to get in, it's interesting to me that we talk about daughter cells during cellular reproduction. We produce daughter cells and that's like, I don't know how, that's a common way that we talk about the cell, baby cells they get produced from other cells. So the DNA in the cell when we divide and make new cells, because we learned that all cells come from other existing cells, they get all the DNA which we will spend a lot of time talking about. Okay, that's your introduction to the cell. In the next section we're going to look at the two main categories. Now I showed you a whole pile of diverse cells. In the next section we're going to divide those into just two types and look at what those are.