 In this video, I'm going to do a quick overview of all of the key structures of bacteria. So if they need, if I need to give you any more detail, I'll do several videos on those topics. I'm just going to use this image and follow right along here in a clockwise fashion. So starting at the top with the fimbrey. So fimbrey in a word, think attachment. So attachment is very important because if an organism can't attach, then it can't colonize an area, which means it can't infect an area and lead to disease. So there are some examples like, for example, if you take E. coli and remove its fimbrey, it actually will not even be pathogenic. The pathogenic strains of E. coli. So fimbrey, think attachments. I always think of cockle burrs or some of them call them sticker burrs. When you walk the tall grass and you come out and your shoelaces and socks are covering these little structures. Well, that's kind of what these fimbrey do. So they're necessary for attachment, which is really the first part of an infection. Okay. So that's fimbrey. Next, we have cytoplasm. Cytoplasm is basically everything inside the cell membrane or plasma membrane, except for what's in the nucleus, which doesn't matter here because bacteria don't have a nucleus. So cytoplasm, think all the guts on the inside of a cell. Now, compare that to cytosol, cytosol would just be the fluid inside of this. Just in case you hear those words, they're not exactly interchangeable. Next we have the ribosome. So the ribosome is the site of protein synthesis or the site of translation if you want to use the fancy terms. So bacterial ribosomes are called 70S ribosome, stands for S, stands for Sphedberg units, whereas most of our human or eukaryote ribosomes are ADS, so that's an important target for a lot of antibiotics. So ribosome, think protein synthesis. The nucleoid or nucleoid region is where the DNA is in a bacteria. So we obviously, eukaryotes have a nucleus that protects our DNA. Bacteria don't. So the bacteria, but all bacteria have one circular chromosome. So it's tucked into this nucleoid region, so that's what the nucleoid is. Next we have inclusion. So inclusion would be really of storage vesicles would be the best way to think of it. This would be like this bacteria would be storing glycogen, so it could be used as a fuel source, et cetera, et cetera. So inclusion just thinks storage vesicles. Next we have the plasmids. So plasmids are wickedly important. We'll talk about them in a couple other videos. The definition of plasmid, and I'll put it up on the screen because it's hard, extra chromosomal genetic material. So it's telling you it's genetic material. It's DNA, but it's not part of that one circular chromosome that bacteria have. The reason these are important is these are vectors. They're self-replicating, so they can make copies of themselves, and they can actually they're transmissible. So this bacteria here could quote unquote infect its neighbor with a gene that actually gives it some sort of resistance factor that teaches it to evade antibiotics or evade our immune response, et cetera. This is part of the reason that bacteria can evolve so quickly. All right. That's the plasmid. Next here we see the flagella or the flagellum. So these are actually way more complex than eukaryotic flagella. So like the flagella on a human sperm is just a single whip-like flagella, but bacteria can have hundreds of flagella on their surface, and they have a rotary motor that actually powers them. So it's quite fascinating. The way I like to think of it is the bacterial flagella has to be this powerful complex machine, the former editor of the journal Nature called it the most complex machine in the universe. But the reason for that is because bacteria are so tiny and there's so much surface tension and forces holding water molecules together. This bacteria swimming through water would be like you swimming through peanut butter. So kind of interesting. All right. Next we have a pilus. So an organism that has a pilus would have usually just one or two of these. And the pilus is generally used to transfer DNA. Now they can be used for attachment and movement, but I like to say when I hear hooves I think horses. The most important thing the pilus does is to transfer genetic material in a process called conjugation. So the pilus might be named a sex pilus or a conjugation pilus as well. Next we have the capsules. So obviously not all bacteria have capsules, but they definitely make them more dangerous. They increase virulence, which virulence is a term for how pathogenic, how dangerous an organism is. The capsule is a substance, a polymer substance usually made of carbohydrates and or proteins that coats the outside of the cell. And the reason the capsule makes these organisms more dangerous is because it helps them evade phagocytosis. So many of your immune cells will engulf and destroy bacteria, but they can't or have a very hard time doing that with a bacteria that has a capsule. So that's the function of the capsule. We'll do a separate video on that. Next we have the cell wall. There's lots of different types of cell walls, but the two key ones would be gram positive and gram negative. We'll do a separate video on that. But the function of the cell wall, it does give bacteria its shape and its structure, but it's primarily for protection. But it's not like protection. Think about like a fortress wall. It's primarily to protect the cell from bursting. So the plasma membrane is very weak and fragile, especially in bacteria. So if water were to rush into this cell, the cell could literally pop if it weren't for the cell wall. So the cell wall thinks shape and structure, but also protection. Then the last structure here on this diagram is the plasma membrane, also known as the cell membrane. So all living things are composed of cells and all cells have to have a plasma membrane. Plasma membrane is a selectively permeable membrane, which means it forces some things to stay in a cell, forces other things to stay out of a cell. And it's also where things move in and out. So the function of the plasma membrane is to keep the things that are needed in a cell while helping to get rid of the things that we have. We have to get rid of like waste products. So very, very important there. All right. So those are all of the key structures here of a bacterial cell or a prokaryote. Have a wonderful day. Be blessed.