Protist Cells

Hi. In this video, we're going to talk about protests, which are essentially the category of eukaryotes that includes everything that isn't a plant and animal or fungus. So it's kind of like a biological grab bag or potpourri. It's a real mixture. And as you'll see, there aren't really a lot of unifying themes that Thai protests together. So let's begin our discussion by talking about eukaryotic cells. Right? Protests? Are you Kerasiotes? So what are you, Kerasiotes? Well, you might recall that you Kerasiotes have, uh, nucleus. They have membrane bound organelles and he's a site of skeletons. Now, the unifying theme of you Karatz, if you will, is the nucleus. And let's use a little fancy terminology here. The sin apa morphy, right? The derived character that is shared between the organisms in ACL aid. Um, the sin apa morphy that unifies eukaryotes is the nucleus right now you carry. It's also tend to be much larger than pro carry outs right here. We've got some a little, uh, pro carry Ah, tick cells. Here we have our eukaryotic cells or eukaryotic cell. I should say one cell and you carry out tends to be a lot larger. It's got this nucleus. You could see all these membrane bound organelles. We have mitochondria here. Uh, these air Golgi apparatus. Right. Um, there's our, uh, century ALS and, you know, here we're really showing it Same same thing, you know, Now you can see the rough er and the smooth E r. And if you want Thio, review these concepts, go back and check out the video on cells. Uh, before we dive into protests. I also want to revisit the idea of endo symbiotic theory. And that is because endo symbiotic theory is actually gonna play into protests in kind of a unique and pretty darn cool way. So if you recall, uh, the basic idea of endo symbiotic theory, it is that as pro carry attic cells which were the first form of cells, got bigger, um, they you know, they faced this problem the surface to volume surface area to volume ratio issue that cells and organisms in general run into as they get larger. And so you know these in folding these membrane in fold ings appeared thio help counter act, um the or thio help maintain rather a surface area to volume ratio. that was ideal for the organism. Eventually this becomes the nucleus and the end of membrane system, and ultimately, now we're going to get to the end of symbiotic part. Ultimately, what's gonna happen is these, uh, thes cells air going to engulf Prodi a bacterium. And it's worth noting that a lot of these single celled organisms, you know, that act as hunters will literally just engulf their prey like this. But instead of digesting this bacteria, what happened is these two organisms essentially became reliant on each other. They formed the symbiotic relationship where they were helping each other. Uh, you know, for example, the larger cell that engulfed the pro dio bacterium's, like offering protection, probably feeding nutrients to the Prodi, a bacterium. And in exchange the pro dio bacterium is going thio generate a bunch of ATP by, you know, oxidative phosphor relations. So eventually these pro dio bacterium through, uh, you know what is called sim biogenesis? Write that down. So, through sim biogenesis, these pro dio bacterium that were engulfed by pro carry attic cells will eventually become a eukaryotic cell, and those proteome bacterium are going to become mitochondria. There's a lot of evidence for this. We're not really gonna cover it now. Um, other than saying that, uh, like pro carry outs which have a double membrane, mitochondria have a double membrane, which is unlike other membrane bound organelles. And the reason I mention that will become significant later. So in addition to this, um, there was also another Sim biogenesis event where cyanobacteria, um, were engulfed and eventually became chloroplasts. Right. So thes are both instances of Sim biogenesis. We have Prodi, a bacterium becoming mitochondria and cyanobacteria becoming horror blasts. Now with that, let's flip the page and talk about how protests experience some unique forms of endo symbiosis.

while the organisms of the plant I lineage, uh, have chloroplasts as a result of what we'll call primary Endo symbiosis. Meaning, uh, they engulfed the cyanobacteria mom, And that turned into the chloroplast. There are lineages of protests that actually have these quadruple membrane chloroplasts. Right? So remember that bacteria have that double membrane structure to them. Right? So chloroplasts, like mitochondria, have that double membrane. But in certain protests that have, uh, chloroplasts present, they have this quadruple membrane chloroplast. And people take this as evidence of what's called secondary endo symbiosis. So basically, um, this organism, this eukaryotic cell would engulf a photosynthetic. You carry out IQ sell like we see happening here, it's going to engulf it. And then this, uh, photosynthetic eukaryotic cell will eventually become this quadruple membrane chloroplast structure. And this will account for the origin of chloroplasts in other eukaryotic lineages outside the plant. I lineage within plant I It is what we see going on right here outside of plant I It is going to be this situation here, right? They engulfed. Now finally, let's actually get Teoh a little bit about road ists. What defines them? Um well, not a lot. Unfortunately, protests again there a grouping of convenience, right? They're basically everything that does not belong to fungi and Amalia and plant. I write fungus, animals, plants. Every you carry out that is not in one of those three groups is a protest. So that means that protests are a para file edit group, right? They're not monofilament IQ. Unlike fungi, animals and plants which are all mono, which are Armando Filipek protests are para Philip Group. So as a group, they do have some shared features. Uh, but many protests will display unique characteristics. And in later video, we will actually go through and look at some of those characteristics. So most protests are uni cellular. Um, but some are colonial meaning that live in colonies and others actually are multi cellular. And these are like brown algae, red algae and slime molds. Those air some, uh, examples of multi cellular protests. Now it is worth noting that multi cellular garrity actually arose independently in many eukaryotic lineages. So, uh, there wasn't some original multi cellular organism, and that's where all multi cellular organisms came from. Instead, uh, many multi cellular organisms have cropped up in various lineages right. So you might remember, uh, when we talked about evolution, we said that the I evolved independently 16/ different times. So just like that multi cellular charity arose independently, many times in eukaryotic lineages. Now, most protests undergo a sexual reproduction, which will include mitosis, unlike binary fission. Right? Remember, protests are you carry out. So they're gonna have a nucleus, which means they're going to need to perform Might Asus when they when the cells divide. However, uh, they generally, uh, sorry. We'll produce undergo a sexual reproduction, but some of them have evolved a various forms of sexual reproduction. And remember, sexual reproduction is a major event in evolution because it allows for the introduction of tons of genetic variation, which is super important for evolutionary purposes. Now, it's, uh, worth looking at this little mock up of a file a genetic tree, and I really wanna emphasize mock up. Um, this is not like a very nice file, a genetic tree. I'm really just trying to show one little, uh, point here. And that is how much? Outside of plants, animals and fungi, how many different lineages there are outside of plants, animals and fungi. So here our keep lasted A This is this is plants, right? This is a plant. I basically, um Now, that's not to say that there aren't protests in this group, but that's where land plants are. We have fun guy over here, and it's e should note that this whole branches coming off of this one right here, um and so fun guy right there and then you can see down here we have animals. So look at all these other lineages that exist outside of plants, animals and fungi. Right? Thes are all the protests Big big group, there big big group. And as you can see, lots of distantly related cousins, so to speak. That's what I meant by the This is not a mon If I let it group, but a parafoil ethic group. There's all these Philip parallel to each other, uh, in this taxonomy, and with that, let's flip the page

As I keep saying, there is nothing that really unifies or defines protests as a group outside the fact that they're all eukaryotes. Um however, there are certain features that are shared by many protests across very various lineages. So let's talk about a couple of those. One of the coolest, I think, is that protests can be multi nuclear hated. And that is when a single EUKARYOTIC cell will have more than one nucleus and you'll see this actually comes in variety of different forms, one of the craziest of which is types of slime. Molds that will take a look at that actually can have thousands of nuclei in a single cell. It is worth noting that there are, you know, human cells, for example, that are multi new created, Uh, and these include types of muscle cells. However, uh, you know, this is just one feature of protests that you can kind of apply generally is like a blanket statement. Of course, there are many protests that are not multi new created because again, the grouping of protests is just out of convenience. There isn't really like one unifying or you know more than one unifying thing that brings them all together. So many protests have cell walls or shells, Actually, even that serve as protective outer layers. Some of these shells are made of like inorganic materials. It's super cool. Uh, some of them are very beautiful. Will actually be taking a look at them when we discuss the various lineages of protests. Now, like all eukaryotic cells, protests can use cilia and flew Gela for movement as well as other things. Um, here we see a picture of cilia here we have our flag. L a. Now I do want to mention that pro carry optic flow. Gela and Eukaryotic flag ela are actually different. Uh, their structural differences between them and, um you know, we have discussed that previously in the video on cells I'm not gonna get into that here. I'm just pointing this out because I am using the same picture of flu Gela that I used when I waas talking about pro carry attic flag. Ela. I just really like the way that these two images look next to each other. So that's why I'm reusing it here. Uh, you're not just know that they are actually structurally different. Um, the fact that I'm using the same image image isn't going to you effect. You are understanding at all. So the last kind of common feature that I want to point out is me Boyd Movement. Now many protests are considered. Amoeba and amoeba are basically organisms that move by reshaping their cells and forming what are called pseudo podia which literally means false foot. Pseudo is false. Podia is foot and you can see an example of these pseudo podia on this amoeba here thes little tentacle like things that it's stretching out. Those are the suit of podia and these air literally cytoplasmic protrusions. Uh and the cell will use acting and myson thio kind of stretch various parts of the membrane out into these pseudo podia. Now it is worth pointing out. Since we're talking about pseudo podia and amoeba, there is a lineage of protests called amoebas OA. But amoeba exist in other lineages as well, because amoeba are simply organisms that reshaped their cells and use pseudo podia or reshape their cells in the form of pseudo podia to move around. Now many protests are actually predators. Yeah, unis, cellular predators, not something we often think about, But trust me, it gets savage at the cellular level, right? You know, they're not, like, you know, uh, stunning their prey or something and taking them out. Nice way. No, they do fag a psychosis. They literally engulf the whole cell and just eat it like that. I almost think like a snake swallowing its prey whole. Now, what's pretty cool is when they do faggots ketosis there, actually using pseudo podia right to stretch out the membrane of the cell around the thing they're trying to eat, which isn't necessarily another cell, but it can be here in this image. It's just as solid particle could be like a particle of food. It could also be another cell, though, Um, for example, like a bacteria cell or another eukaryotic cell. Um, it is worth noting that some protests actually do use photosynthesis. You might recall we just talked about secondary end of symbiosis, right? So there are chloroplasts in various forms present in, uh, in different protests, and they will do photosynthesis. Though many protests do not rely solely on photosynthesis, they will, uh, do some photosynthesis. But then they'll also, you know, obtain nutrients in other ways now, De composers, actually. Oh, before I get to that, I love this picture right here. These are protests and these dark dots, those air red blood cells. Yeah. So these air protests that air eating red blood cells inside an animal. As I said, it gets savage on the cellular level. They eat your blood now A z I was saying D composers absorb nutrients directly across their cell membrane. Uh, usually, this is accomplished via transport proteins. So, um, uh, many protests are de composers, and they will break down and absorb nutrients from decaying organic matter. And again, they'll take those nutrients in the transport proteins. So these are just some themes that you can apply to produce. But again, bear in mind that it's really not a very well defined group. It's really just a everything that isn't this stuff group with that. Let's flip the page