Fungi

Hi. In this video, we're going to talk about fungi, which include molds, mushrooms, yeasts, mildew, all that lovely stuff. Now fungi are hetero trophic. You carry outs, and they generally have a hap Lloyd nucleus, and they tend to be the main D composers in many ecosystems. And this is a very important feature of fungi that we're going to return Thio again and again. And here you can see a couple examples. We have morel mushrooms, which are absolutely delicious type of mushroom. You hear these? A monogamous Kariya. These will kill you, don't eat those. And of course, this is the most important mushroom, the power mushroom. Now some fun guy, our mutual ists. And that basically means they exist in relationship with another organism that benefits both of them. And this is another one of those really important properties of fun guy, and you'll see why momentarily now fungi are essential to many land plants. You often think of these as being two completely separate organisms. But the point that I'm going to try to drive home to you is that most land plants would not be able to survive without fungi, and the reason is because of this mutual ist relationship. They share this symbiosis. They share now a couple examples of some fungi relationships, not the kinds that end in bad breakup. The good kinds are end of fights, which are basically symbiotic fungi that live inside plants. And they benefit the plants that in which they live, and the plants in which they live benefit them, and they lived happily ever after. That's not to say that things can. The things always work out well, as we'll see soon now, like in our in especially cool example of mutual ist fungal relationship. And it's a symbiotic association of fungus and algae, or sometimes a cyanobacteria, the main point being a uni cellular organism that performs photosynthesis. Now, in this example, here we see in blue the fungal body. We'll learn more about what fungal bodies are made of momentarily, but for now, just think of that is the body of the fungus, and it's wrapped around these algae, and essentially, these two organisms are going to help each other. I mean, algae perform photosynthesis right again. This could be cyanobacteria, But for the sake of my example, I'm just gonna talk about algae so algae perform photosynthesis, meaning they're going thio generate organic compounds that the fungus can feed off of in return. The fungus helps ah, secure water for the algae and also helps prevent it from drying out. It essentially acts as a protector, and it also can provide certain nutrients to the algae, so they live together in harmony. Very, very cool organism. You can see a picture of some liken right there. It's a little like, like and clump like and actually come in all different shapes and sizes. That many different morphology is really cool organism. Now, last thing I want to say is that some fun guy are actually or some phone guy have symbiosis. That air obligate that is to say, there, uh, they exhibit obligate symbiosis, meaning they have to live in a symbiosis in order to survive. Now, Other fungi in many fungi. In fact, uh, our faculty native. And if you recall these terms from when we talked about, um, cellular respiration, specifically aerobic respiration, uh, you might recall that obligate means you have thio and faculty Native means you can, but it's not necessary. So some funk I can, uh, have symbiosis but they don't necessarily need them in order to survive. They might just survive better with them, Now said. Not all these relationships and well, well, it turns out there are a bunch of fun guy that are parasites, and they'll infect plants and animals. And when they infect animals, we call this my casus. Now fungi tend to be the main D composers, as I said, and what's really important is they're able to digest plant material, specifically cellulose and lignin. You might remember previously when we talked about lignin, we said it was a tough material and thinking way far back to when we first talked about Celie List. We actually talked about the fact that cellulose cannot be digested. If you're curious as to this lesson, I'm referring Thio. The lesson on carbohydrates in the biological molecules chapter. Now cellulose can't be digested by animals, but fungi can digest cellulose, so they're actually a bunch of fungi that live in the guts of various animal species that help those animals digest plant material by breaking up of cellulose for them as well as the lignin, for that matter. And what's so important about this is because plants take so much carbon out of the atmosphere, right? They take all that co two that we animals put into the atmosphere. They take it out and they build it into their bodies. Right? And if nothing is done about this, then that carbon just sits there. And eventually those plants, the carbon and those plants will turn to what we know is coal today. Um, but fungi return this carbon to the carbon cycle. So they break down that non digestible plant matter or what's non digestible? Thio many other organisms. They break it down and they return that carbon to the carbon cycle. And actually, we have a special term for fun. Guy that feed on dead plant matter specifically right. If you're feeding on live plant matter Well, probably parasite, Right. So fun guy that feed on dead plant matter are called sacrifice. Now, here I just want to point out this parasitic fungal infection all these little tubular pink spaghetti strands, whatever you want to think of them as branches, they kind of look like those are part of the fungal body and this is animal tissue around it. So that is a fungal infection in an animal. And over here we can actually see the fungal bodies that are in the process of decomposing or fungal bodies that will be part of organisms that are going to decompose, plant matter and return carbon to the carbon cycle. Now, before we turn the page, the last fungus I wanna give a shout out to is yeast, my favorite fungus. The often overlooked fungus, however, it it's a wonderful organism. It's Ah Eunice cellular fungus. And as you'll see, most fungi outside of yeast are multi cellular, and it is the fungus that's responsible for leavened bread and beer. So we have been humans that is, have been using yeast for an enormously long time. I mean, it's hard to really say I you know, I'm not an expert on anthropology, but it's Humans have incorporated yeast into our cooking processes and are brewing. Process is for a very, very long time, and they're awesome organisms, and they actually have many similarities to human cells, which is why they're used for a number of, um, studies, including genetic studies to you learn more about humans. So go yeast, Easter. Awesome. And with that, let's turn the page

now, fungi. Morphology is going to be a little strange. Let's say, compared to what we've seen thus far, fungal bodies are mostly made of what are called Haifa. These long filaments that are actually, um, made up of one or sometimes many, many cells and are surrounded by a kind of tube shaped cell wall that will enclose all of them in a filament, you can see a microscopic image of Haifa here. Um, there these Phil mentis strands, you see, and we can see a non artist rendition of a Haifa here. Um, each of these blocks actually represent individual cells and essentially, um, they While the cells are, uh, technically independent, they do have pores between each other and, um, these blockages or these divides in the cells, I should say they're not actually blockages. They allow passage between the cells. These divides are called SEPTA. So here this is a septum. That's gonna be the singular form of the word. And it's worth noting that, um, these fungal cells right, these Haifa have a kindness cell wall which is actually a modified beta glucose polymer. You might remember that beta glucose is what is used to make cellulose. Interestingly enough here, however, the sub units have been modified with and amino acid like group and essentially, uh, it this'll polymer. Um X is a tough sell wall for the fungal cells, and it's actually also present in insects shells, interestingly enough, And that's why when bugs die, their shells hang around and don't decompose or anything. Because, uh, there's really not a lot that digest kite. It's a very tough, resilient material. That's why you know, you can keep, for example, an insect shell from a dead insect from, you know, really, really, really long time ago, and also why fungi tend to be or tend to have these resilient, hardy cell walls. Now Haifa refers Teoh, a Nen vivid jewel filament, and we use the term Hi Fay Thio. Refer Thio Multiple Haifa. So that's the plural form. The entirety of a fun guys fungus is Hi hi fi Hi Fay are called the Mycelium, so that's essentially the the mass of the fungus, which is made up of all these interwoven haIf A that is called Mycelium. So you might hear those terms used interchangeably from time to time. But just know that mycelium is that the totality of the Haifa Haifa of Ah, Phangnga the totality of the haIf a of a fungus say that five times now, fun guy actually perform what's called extra cellular digestion. And essentially, what they do is they release enzymes and absorb the nutrients that get are The enzymes will break down compounds releasing nutrients, and these nutrients get absorbed through thief fungal. Hi, Fay. Now it's worth noting that might sound really strange, but humans technically also perform extra cellular digestion, Right? We put food into our gastrointestinal tract, and we release enzymes from cells around the G I tract that break down our food. And then those cells absorb the nutrients as the food gets broken down. The difference, really is that, um we're doing this inside of our bodies, whereas fun guy, uh, don't always, uh, funk. I don't usually do it like that. They will actually, uh, x or secrete these enzymes to the environment, break down the stuff and then absorb it. So, uh, not as weird as it sounds, but still different than the way humans do it. Now, some parasitic fungi actually have these. A special hi Fay called Historia and again singular here is gonna be a story. Um, all these Latin words I know, Um, so ah ah, story. Um, that's gonna be the singular form. And you can see them here. These air all plant cells and these dark bits that you see inserted into the plant cells. Those are the historia, and you can tell because the fungus has been stained this darker stain. So this band, you see, that's the fungus. And these nubs, it's inserting into the plant cells, those air, the storia. And this is what parasitic plants air gonna dio uh, some parasitic. I'm sorry, some parasitic fungi you're going to do to extract nutrients from plant cells. Now, with that in mind, fungi actually generally are really helpful to plants. Okay, so sometimes their parasitic always some bad apples in the bunch, right. But, uh, fungi are actually essential thio many, many land plants. And they actually formed this symbiotic association of haIf A and roots of vascular plants. Obviously, because vascular plants are the only plants that have roots and a supposed to resides might recall from plants. Now, this association of roots and fungi can be seen here in white. That is the fungal body and the little brown bits are roots. Basically, what you're looking at is, um, someone kind of like pulled a plant, flipped it upside down and brushed some of the dirt off the roots. And that's that's what we're looking at here. Now there are actually two ways that these micro Resi can form and notice that term. Micro resi right riz I that's referring Thio roots Maiko is referring thio fun guy. So we have fungal roots. Basically now, as I said, they're essentially two different versions of my core. Is I the Actually, it gets a little more complicated. You know, Azaz, I hope you realize by now we have to simplify things a little bit just to make it manageable, to talk about and to paint some broad strokes pictures. But essentially you can have Acto Acto Micro is I which, uh, form on the outside of plant cells the extra cellular surface. Um, they don't penetrate into plant cells, and you can see an example of this right here we have the artist's rendition in purple thes purple stringy bits. Those are the fun guy, and you can see that While they don't actually penetrate the plant cells, they will penetrate into the root of the plant and grow around the cells. And here you can see a new image on image of the Ecto Mike. Or is I around a route? So we're all this stringy stuff. Is the fungal body forming around the route? But it can also go the other way. Our bus killer fungi, which are sometimes referred to as Endo Micro Rizal, right endo, meaning internal. So our bus secular fungi will actually penetrate into the cells in the roots of plants. Um, however, in both instances, this is a beneficial relationship to the plants, just two different strategies. So the, uh, the main relationship here is that the fungi helped the plants get certain nutrients and help them obtain water. And in return, the fungi are provided with nutrients by the plants. So with that, let's conclude this video and I'll see you guys next time