all right welcome back um this is organelles part two so the next set of organelles we're going to talk about are only found in eukaryotic cells so we're talking plant and animal i will we will talk about um if any are found in only one or the other okay so first organelle we are going to talk about is the endoplasmic reticulum or er so this is a diagram of the er and you're going to notice we're going to talk about both a smooth and a rough er so first let's talk about what these are so the endoplasmic reticulum is a network of membranes and every time you hear the word membrane now you will think phospholipid bilayer okay so this is a continuous it's hard to spell sometimes um in front of people even though i'm not in front of anyone continuous network of membranes and what i want you to see is it is continuous with the nuclear envelope see that right here so it goes from nuclear envelope and that develops right in to the er so they're all interconnected usually when i draw it i would have my nucleus here and then i just kind of draw these like that's how i diagram the er so you can you can kind of see that um we have a rough and a smooth so the rough er is rough because it has all these little dots on it which are ribosomes so it has ribosomes attached so hopefully you go ding ding ding ribosomes cytoprotein synthesis rough er must also be a site of protein synthesis so the rough er is in fact a site of protein synthesis and we will actually talk later this semester that proteins can be made on free-floating ribosomes and on the rough er in eukaryotic cells the rough er is also not only a site of protein synthesis but also let me go back to red so we keep this all together and protein modification and we're not really going to talk about this much this semester but it's really important when you take cell biology we'll talk a lot about protein synthesis um i think you probably also cover it in genetics okay so let's contrast that rough er to the smooth er okay so the smooth er is smooth because you can see there are no attached ribosomes the smoothie r is very important for um i'm gonna put a function sorry i write it as slant because i'm my tab tell it's like not flat so i'm having a hard time figuring out how to write but sure by the end of the semester i'll be awesome the function is to make lipids and carbohydrates and we'll talk about all these macromolecules like another week or two it makes some hormones like estrogen and testosterone um it also has a roll so it's a producer i put up here it also has a role in what we call detoxification so your um liver the cells in your liver are full of smooth er where a lot of drugs alcohol other foreign molecules um come through and get detoxified by the smooth er and the detoxification is so that we can get those chemicals out of our body in the muscle cells and in other cells but especially in the muscle there's a storage of ca2 plus which you may or may not know is calcium so calcium ions are also stored in the smooth er what's really super cool is that these two being continuous network of membranes um they can kind of change so smooth ergonomy can become rough if the protein needs if the protein if the cell needs to make a whole lot of proteins then more ribosomes will start to attaching and it will become rough er or like i said in the liver if you really need to work on detoxification you'll lose ribosomes and the rough er will become smooth er pretty cool again eukaryotic cells both plant and animal and these are just some tem micrographs of the smooth and the rough er so this one hopefully you recognize as a rough because it has all those dots on it this one is smooth and it's interesting they kind of change shape so you can see that the rough this is why i draw it like this you know it's it's just this back and forth back and forth network and then the smooth seems to be more tubular and that just is based on how they're working their function okay so this is near the nucleus right continuous with the nuclear membrane the next organelle in all eukaryotes plants and animals is the golgi apparatus okay this is the one organelle that you must capitalize because it's named after the scientists that discovered it golgi this is different this is a series of individual stacks uh sex stacks of sex series let me just write it series of individual saps or membrane sex i should say okay so every line you see here that's your membrane and what i want you to see that's different is that these are not connected okay they're individual so it's not a network like um oops like the um er you can kind of see that here's a tm and you can see i should change color so i could actually you can actually see what i'm drawing you can see all these individual sacks so some people say it looks like a stack of pita bread or a stack of pancakes um the function of the golgi is to sort package tag and distribute okay so let's write that sort package tag and distribute proteins and lipids hopefully you can read my writing um so the golgi some people describe it as the ups of the cell so it gets you can see incoming it gets stuff usually from the er and it will sort it it will maybe tag it with sugars or other modifications so that that molecule knows where to go in the cell it will package it into these vesicles which is our next term and distribute it to the right parts of the cell again yep all eukaryotic cells plants and animals so let's talk about these little vesicle things so um we have two terms here vesicle and vacuole so both are membrane sacs so we get lots of membrane sex so remember um eukaryotic cells are full of what we call membrane-bound organelles so we have membranes so that we can have distinct functions in all of these different organelles parts of the cell remember that also allows the cell to be a little bit bigger or not a little bit a lot bigger than a prokaryotic cell because it has all these specialized organelles in it it helps move things around better um vesicles in general are for transport okay so moving things from one place in the cell to another so you can see down here from our rough er we have a transport vesicle that's bringing say some proteins to the golgi and then from the golgi we have what we call a secretory vesicle that is going to take uh these proteins to the plasma membrane to secrete them so sometimes vesicles will have these special modifier names transport secretory things like that again you'll really get into this in cell biology um vacuoles in general are more for storage so the one vacuole that i want you to know about is the central vacuole and this is only in plant cells now there are all kinds of vacuoles in animal cells plant cells protists i'm guessing fungi i don't really know but we're just going to focus on subsets here so the central vacuole in plant cells excuse me it's for the storage of water so it's huge it takes up a huge it's hard to see here huge space um in the plant cell and what's really cool so if you've ever and i wish i had videoed this the other day so i have this big um planter full of catnip for my cat and he goes out there every morning and munches on it and then like passes out and i went out the other morning and one of the containers it was all wilted over we'd forgotten to water it the day before and i was like oh man i just lost all this catnip i thought well i'm just going to try it so i gave it oh sorry i've been not moving around in my office enough i gave it a whole bunch of water and these will too like i really thought they were dead plants sucked up that water came back to life looked beautiful and that's all the central vacuole so that central vacuole has to fill up with water and make the plant cell like super full so that the plants can stand up so like i said i thought these guys these plants were gone i wish i had videotaped maybe i won't water them tomorrow and video let's post it for you okay so we've got vesicles vacuoles both are membrane sacs slightly different um functions one's for transport ones for storage in general vesicles in all eukaryotic cells peroxisomes and lysosomes wow guess what these are these are small sacs these are membrane sacs too okay but these inside the membrane sacs they have enzymes and enzymes are type of protein we'll talk about in another week or so and these enzymes make chemical reactions happen so they both have membrane sacs with enzymes right over here to break down different molecules in the cell and by breakdown think like digest so that we can recycle reuse parts of the cell or molecules in the cell okay i would never ask you to look at a picture and decide which is a lysosome which is a proxysome which is a vesicle because they're all membrane bound sacs they look very similar under the microscope these two have slightly different functions so lysosomes they use enzymes called acid hydrolases and they can break down things even big like old organelles so if you have a we haven't talked about mitochondria yet but you probably heard that term so if you have an old mitochondria that's not working well um a lysosome will surround it and then break down that old mitochondria and we can reuse the parts so it can break down old organ nails or material from outside the cell so if we go back one slide you can see that this is a picture of what we call a macrophage and that's part of your immune system and what macrophages do is they go around your body and they're looking for foreign objects like bacteria and so what this macrophage did was it took its membrane and made a circle a membrane made of vesicle around that bacteria and then here comes the lysosome which is another membrane sac but now it has but it has enzymes in it and these two um mush together remember i told you all these membranes just like bread dough play-doh can mush together and now you're digesting this bacteria into all the little pieces so you're destroying it saving your body and then you can reuse parts of it so that is oh it kind of maybe is opposite that's a lysosome um a peroxisome um works in detoxification different methods than the smoothie er it also breaks down fatty acids and amino acids which are parts of proteins so the peroxisome here is just a little bit more specialized but they're both functioning to break down molecules and they're both membrane sacs with enzymes okay this is where there's a thing to note so peroxisomes are in both animal implant okay lysosomes you find in animal cells lysosome function in plant cells are in a vacuole so like i said vacuoles are for storage pretty much but the more you learn about biology the more you learn that any kind of rule you try to make it gets broken by something so plant cells let me just write this down here cells use a vacuole not the central vacuole just another vacuole for the lysosome activity so they can still break things down they just do it a little bit differently okay i think i got all of that um so the endomembrane system is basically the organelles we were just talking about so it consists of the nuclear envelope the er the golgi vesicles the lysosome and the plasma membrane so there's one two three four five six six parts and this is the figure i just showed you earlier this system works to make modify sort distribute all of our proteins and lipids so it works together to create all these molecules that we need in our cells so that is the endomembrane system endo means inside membrane system and and one of the reasons um this internal membrane system works is like i said you can have vesicles let me do a different color you can have vesicles butt off from say the smooth er and go and smush into the golgi and then butt off and go where it needs to go and this is a youtube link from your textbook it's pretty good just goes walks you through the endomembrane system okay we have one more kind of classification of molecule organelles that we're going to talk about and that is the cytoskeleton this again is in eukaryotic cells and these microfilaments intermediate filaments microtubules these are all protein fibers and we'll talk about proteins in the macromolecules of the cell but hopefully you've thought about protein right you need protein in your diet proteins are one of the most diverse of macromolecules as far as functions in the cell so i mentioned enzymes are proteins now you know that the cytoskeleton is also made of these long protein fibers you've got three types and we're going to talk about each type in a second individually but in general what the cytoskeleton does is it maintains the cell shape it helps for cell movement and it just kind of keeps everything organized so it keeps different organelles where they should be it we'll talk about this minute microtubules act kind of like train tracks so things can move in orderly fashion fashion um prokaryotic cells do have a type kind of cytoskeleton but it's nothing like this so if you're when you're filling out your chart we say that prokaryotes do not have a cytoskeleton but plant and animal cells do okay and this is an image um showing you um the different types of cytoskeleton so here in a you have what we call micro and like i said i'll talk about the individual functions in just a minute these actin ones are called micro filaments and this one in yellow is called an intermediate filament and what i want you to see is that the microfilaments are the thinnest the microtubules are the thickest and gosh guess what the intermediate are right in the middle there okay so let's talk about the functions so microtubules these if you're going to describe them they are hollow tubes right remember made of protein some of their functions in the cell they're like the train tracks so for moving things around in the cell there are these really cool things called motor proteins that will like hold organelles and vesicles and walk down these microtubules back and forth to take things in an orderly fashion from say the er to the golgi so train tracks in the cell and you can see these are all stained green it's really pretty for movement of vesicles and organelles as i should put train tracks um microtubules also make up what we call the spindle fibers that are important in pulling chromosomes to separate cells in cell division whoa okay so spindle fibers for oops for separating chromosomes during cell division microtubules also make up something we're going to talk about in just a second they also make up a thing called a centriole they make up flagella which we'll talk about in the last video and cilia are made of these hollow two proteins microtubules the next one we're going to talk about is microfilaments the skinniest one and these are shown in red and sometimes they're also called actin filaments and they're really important for cell movement so some cells in your body like white blood cells actually can crawl along finding foreign objects part of your immune system so cell movement excuse me oh sorry um actin filaments or microfilaments are very important for they are super important in your muscle cells so this is how your muscles contract actin and myosin they are also important in dividing the cell so in dividing the cytoplasm during mitosis and meiosis they really help you can see they're all over the place with cell shape microfilaments are important for cytoplasmic streaming so if you don't know what cytoplasmic streaming is it's really super cool go click on this youtube video um you can see it really neat in plant cells under the microscope so live cells and you see the chloroplasts kind of moving around in this really organized fashion in order to get the best light for photosynthesis which we'll talk about in the last lecture um so check that out it's really cool okay that's our microfilaments and then um oh and so a description of these did we do yeah we said hollow tubes this is um two strands of actin intertwined that's how you would describe it and recognize it so if you see these two just two strands that's a microfilament if you see something that looks like a hollow tube that's a microtubule and then if you see something that looks like a whole bunch of strands together so this is multiple strands twisted together that is an intermediate filament intermediate filaments are important for cell shape they're important for cell structure they give the cell strength to reduce to not like fall apart and to help in stress like your cells are getting smooshed or stretched so cell structure cell strength really super important for the structure of the nucleus and there are lots of different types of inner intermediate filaments um including like what makes up your nails things like keratin but what's really i think fascinating is that there's different types of intermediate filaments and different cell types so in different tissue types in your body and one of the ways they can figure out if you have cancer that has metastasized so that means cancer that has moved from where it started they actually analyze the intermediate filaments and they can tell where that cancer came from did it come from your liver did it come from the breast tissue um did it come from i don't know wherever cancer comes from they can tell that by the specialized intermediate filaments i thought that was cool okay last slide before we stop this lecture centrioles and the centrosome so i mentioned that centrioles are made up of microtubules and these are essential for the division of chromosomes so a centriole is actually made up of a whole bunch of microtubules so each of these rods is a microtubule that comes together to make that centriole these are only found in animal cells and they're always found in pairs and they can actually um replicate and divide um and what their function is is you can hardly see them let's see if i can i never can zoom in when i want to i only zoom in when i don't need to okay never mind um the centrioles are right here and there's this area called the centrosome so centrosome is an area where the centrioles function and what is made from these centrioles is these things called spindle fibers these spindle fibers are also microtubules and what it's trying to show you here is that they're connecting to these replicated chromosomes and as the cell divides the spindle fibers pull the chromosomes towards the different centrosomes and then the cell will split down the middle so we'll discuss this more when we talk about mitosis and meiosis here's an electron micrograph you can see the centrioles right there okay i'm going to pause and we will come back and finish up with cell wall chloroplasts mitochondria endosymbiosis flagella and cilia and fimbre and pili so we're kind of now going to the outside of the cell all right i will see you at the next lecture