What's up everybody! So in this video we're gonna be talking about organelles and compartmentalization just like this little frog is in his little leaf compartment here and we also got to talk a little bit about tools for research which will make sense when we get to that part in this video. So we know right we know that there are two big categories of cells that exist right prokaryotes and eukaryotes and we know animals and plants they belong to the eukaryote cell category right Now what is a big difference, one of the key differences between eukaryotic cells and prokaryotic cells? We know there are many differences, but one of the key ones is the fact that eukaryotic cells have membrane-bound organelles, right?
They have the mitochondria, the nucleus, all of these organelles, which prokaryotic cells do not have, right? They do not have these organelles. So that's a very key difference, and we're going to talk more about that in this video. So when we look a little bit more, we... Let's zoom into this eukaryotic cell here.
We can see that it has a lot of organelles as I just mentioned. Now in another chapter, we learn all about eukaryotic cells and what the functions are of all of the organelles, right? Because each little organelle has its own little specialized function like the mitochondria is supposed to make ATP, your nucleus stores your DNA. These little things here destroy everything that your cell doesn't need, right? All of these have their own function.
So for now, Just to test yourself for fun, don't worry, it's not part of this chapter. See if you can label all of these structures in this eukaryotic cell. Okay, here they are, in case you can test yourself to see if you got them right. It's not important, don't worry, for this specific chapter.
We talked about it in another one. In this chapter, we need to understand a little bit more about a little concept called compartmentalization. Okay, compartmentalization.
We need to know this definition. We mentioned it before but now we need to really understand it. Okay, so Compartmentalization, what is it?
It's just exactly like the word sounds How a eukaryotic cell has this ability to have little compartments little rooms in a sense that are these organelles, right? So if we look at the official definition it refers to the division of cells into different regions With one or two membranes causing the separation essentially these regions are these little organelles, right? That's what compartmentalization means And we know that prokaryotic cells do not have this ability.
Now, what exactly are organelles? So organelles are these membrane-bound regions or subcellular structures that carry out specific functions. So we know all of these little compartmentalization is essentially forming all of these little regions enclosed by a little barrier, right?
Now, these little things are called organelles, right? So they are membrane-bound, meaning they have little... membrane around them separating them from the rest of the cell.
They are subcellular meaning they're inside the cell. They're not bigger than a cell or outside of the cell. They belong inside the cell and they each have their own specific functions.
That's very important. We need to know these two words compartmentalization and organelles. They're very related terms. Organelles and compartmentalization. Now we need to know, this is a little strange part from the book that doesn't make that much sense, but I'll try and make it as much sense as possible.
So here we have a lot of cellular components, right? And we're going to say here if they're an organelle or not. So what you need to know from this chapter as well is that these three here, the cytoplasm, the cytoskeleton, and the cell wall, are all examples of things that are not organelles.
Now why? If we look at the definition of an organelle here, why on earth is a cytoplasm not an organelle? Okay, let me clear that up for you. A cytoplasm is not an organelle because, think about it, it doesn't have a specific specific function.
The cytoplasm is just a general term that refers to everything within the confinements of the plasma membrane. Anything, everything inside the cell is considered the cytoplasm, right? So all the organelles, like the nucleus and all those things, are within your cytoplasm. within the confinements of the plasma membrane, right? So if we go back to this picture here, all of this here is the cytoplasm, okay?
The cytoplasm contains the cytosol, this fluidy part, plus the organelles. So therefore, the cytoplasm is not actually an organelle, right? So here's some words, you're gonna read that. Okay, what about the cytoskeleton? So in the other chapter where we learned about eukaryotic cells, we know the cytoskeleton is, we can't actually see it in this picture here, but it's little fibers, little like structures that make the cell keep its shape.
Okay, it's little, it's like a framework. You know when they build buildings outside, they have a lot of these frameworks that make the structure of the building so it stays that way. It's the same with a cell. A cell also has these little things that do that and we call them the cytoskeleton.
And you can watch the video on that. eukaryotic cells, if you want to understand that. Now these are not organelles.
Why? Okay, the reason why they're not considered an organelle is interesting, because they technically have a specific function, right? I just mentioned it. They have a specific function to keep the cell structure, right?
Now they are subcellular, because they're inside the cell, right? They're inside the cell, but the problem is they are not membrane bound. So if you think about your nucleus or your mitochondria, it has a little membrane surrounding it.
Now, a cytoskeleton does not have that membrane. It is just little fibers, little poles, little structures inside your cell that isn't surrounded by a membrane. They're everywhere.
So for that reason, the cytoskeleton is technically not considered an organelle. Okay, now one more here is the cell wall. Now remember, this one is only found in plant cells. You know, if you look at your plant cells, so we can go back here. You have two layers, right?
The most outer one is your cell wall, and then we have your plasma membrane, and then we have the inside of the cell. So the thing is, the cell wall is not considered an organelle, because organelles are typically located within the cell's cytoplasm. And the cell wall, if you think about it, is actually outside of the cell.
It's like in the very outside of the cell. So it's not within the confinements of the plasma membrane. It's not within the cell.
So for that reason, some people like to think it's not an organelle. So I want to make something very clear here. This is what the IB wants you to know.
So for the sake of the IB, just remember, the book makes it very obvious, that you need to remember these three are not considered organelles. Because of these reasons that I specified. There are some examples here which I don't really agree with, but don't worry about my opinion.
This is what you need to know for the IB. For example, rough ER makes sense. It's got a membrane around it.
It's got a specialized function. So sure, it's an organelle. Same with the smooth ER. Same with the nucleus, same with the lysosome, but then the ribosome I don't agree with because this one, think about it, it is a little structure inside your cell which technically has a specific function but according to the definition it does not have a membrane around it. It is just a little structure floating around in your cytoplasm, right?
It's like these little things. They don't have a membrane surrounding them. So according to me, it would not be an organelle.
And according to a lot of sources as well, if you Google around, you'll see. A lot of sources consider ribosomes not an organelle, but then other ones do, like this book. So same with the, same with the, there's one more example I remember.
It was the flagella and the cilia. They're little like tails, right? For example, sperm has a flagella, a little tail.
It is technically not inside the cell. It is technically a part of the cell and has its specialized function, but it's not surrounded by a membrane. So same with the cilia.
So technically, I don't think it's an organelle, but the book does. So that's what's important. So make sure...
If it doesn't make sense to you, like it sort of doesn't make sense to me, don't worry, okay? Just remember, for the IB, these three are not organelles. And this is the reason why.
These are the reasons why. The rest are considered organelles, okay? Even though ribosomes and vasculature, maybe there are different opinions on it. Some sources believe ribosome is one, maybe other ones believe it's not. Don't worry about it, it's not important.
Just remember, the IB wants you to know that these three are organelles, not organelles, and the rest are, okay? That's it. Okay, great. So now what is the point of compartmentalization? I just told you what compartmentalization is, right?
The definition. We know what it is, right? Remember here, the vision of the cells into these different regions, which we can call organelles, right?
Compartmentalization. Now what's the point of this? There are three very important reasons and I hope they make sense because I think they're very interesting examples.
One, danger. Let me show you. You know there's an organelle, this one here, the lysosome.
Right, which looks a lot like this structure here. It's got a membrane right which is important to be considered an organelle And it's got all of these little molecules inside these enzymes remember enzymes are little things that like to make things happen And they're like little tools, but these enzymes are hydrolytic. So they're very dangerous They break things down because lytic means to break things down.
So these enzymes love they're very dangerous like to destroy things It's like a scissor right these little enzymes like a scissor I could break things down now this lysosome its whole purpose is to host to hold all these enzymes and whatever your body, whatever your cell doesn't want or thinks is old, it doesn't want it anymore, it will send it to this lysosome. So this lysosome is like a little trash can in a way, okay? So this lysosome will receive this old thing or whatever the cell doesn't need anymore, and these enzymes will break it down, just like throwing it in a trash can, essentially.
So the purpose of the lysosome is to break down the old proteins, lipids, carbohydrates, nucleic acids, whatever your cell does not want anymore, wants to get rid of, okay? Very important. Now, imagine... This lysosome was not compartmentalized. Imagine there was no membrane and all of these enzymes could go freely throughout the whole cell.
That'd be very bad because guess what your cell is made of? These very same things. Proteins, lipids, carbohydrates, nucleic acids. So these enzyme would just kill your own cell. Imagine that.
So this is one reason why compartmentalization is really important. Certain enzymes which only belong in one area of the cell can be kept that way so that the whole cell is not influenced by those enzymes just like this example here. Because the very same things that get old and needs to be thrown in the trash can is a part of your normal cell.
So if these enzymes float around everywhere, your whole cell would be destroyed. So that's one example of why compartmentalization is super, super important here. Okay, next one is vesicle formation or endocytosis. Okay, let me show you what I mean. So you know your cells, right?
They can uptake things with many ways. If you look at the membrane transport video, there's many ways, including... Endocytosis.
Endocytosis is one way of bringing things in. So for example, let's say there's a virus and it's gonna infect your cell This blue thing is your cell. It's very simplified cell. There's no nucleus or anything. I'm just trying to prove the point here So imagine your cell gets infected by this virus.
This virus comes and your cell up takes this virus Now your cell up takes this virus. Okay, but it doesn't let it go straight into this into the Cytoplasm, okay, it's putting it into a vesicle. So it's holding it kind of like in a little bag making sure that it doesn't get into contact with the rest of the cell. So this compartmentalization, this forming of a little vesicle, right?
This little like a little vesicle allows the virus to not get in contact with the other organelles in your cell, right? It kind of isolates this thing. It quarantines it to make sure it's not going to hurt the rest of the cell. Now, in that way, for example, if your cell realizes this is a bad thing, it's going to fuse with a lysosome, like I just mentioned. And this lysosome is going to go and...
put all of its hydrolytic enzymes into this little vesicle and it will destroy the virus, right? So vesicle formation is very important as well. It makes this compartment which separates it from the rest of the cell.
Okay, that's very important Sometimes it's not necessarily a virus that you put into a vesicle But something good something that the cell like a little package that the cell receives from another cell And it wants to take it in and use it in the cells Sometimes it's a good thing and you wouldn't and you would um, you wouldn't want to destroy it So it's not only for endocytosis, it's not only for bad things like viruses or bacteria, it could also be for good things, okay? So bear that in mind. So these are now two examples, danger and vesicle formation, okay? Let's look on to the last one, last one here.
So it enhances cell efficiency. Why? Why does compartmentalization enhance cell efficiency? Okay, so I'm going to use an analogy here.
So think about a school. Imagine, you know a school, right? It has a lot of... different classrooms.
You can think of these classrooms as different compartments. Your school is compartmentalized. You have a gym where you guys do PE or physical activity.
You have your math class. You have your science class. And then you have the cafeteria where you eat lunch. So in a way, your school is compartmentalized, right?
The same way a cell is. Now, why is that important? Imagine your school was not compartmentalized. Imagine all of your classes happen in the same room. So for example, you're...
Say grade 6 has math from 10 to 11 and you have science from 10 to 11 and you guys go into the same classroom and you have two different teachers speaking at once with two different classrooms happening at the same time. Wouldn't that be such a mess? All of the teachers would be interfering with each other because you couldn't hear your own teacher speak.
You'd hear the other teacher speak and the one class would be discussing something while your class is trying to listen. Right? It's a mess.
So if... That is what happens when there is no compartmentalization. When your school is not compartmentalized, it would be a mess.
Nothing would be organized. Nope, nothing would run smoothly. Nothing would be controlled and there'd be so much interference, right? So it's the same thing with the cell.
This compartmentalization is super critical because it allows, for example, the mitochondria to do its own thing in peace. It allows the nucleus to keep its DNA in peace. It allows everything to happen in its own little room at its own time. Everything is smooth.
Nothing is interfering with each other, right? Because the mitochondria has its own enzymes. So its enzymes are right here in a concentrated area. It can do everything as fast and as quick and as efficiently as possible. It's not floating around everywhere and everything is messed up and the enzymes are all over the place interfering with each other.
No, it's nice and organized and everything can happen very efficiently. So this is why this is, I hope this analogy helped of the school because basically compartmentalization enhances cell efficiency in this way. Okay, so we need to look at one last little example here I don't like this one too much because at this point you guys don't know about this process much yet So you just get the overall picture so here We're gonna basically illustrate a little bit this one here enhancing cell efficiency with a more real example So here we have our nucleus right and the nucleus is where your DNA is, right?
Remember your DNA codes for proteins, right? I talked about this in the protein video. So your DNA is the code It's the instruction manual that your cell is gonna read to make proteins It's so your cell makes proteins from DNA now DNA is made proteins are made I mean by a by two processes, transcription and translation.
Don't worry about, this is a huge topic, so don't try to understand it now, it's not going to happen, okay? It's a huge separate topic, which I have to make a whole video on, so don't worry about this. I'm trying to understand, what you need to get from now is just an overall concept. Wait, this is cringing me. Okay, good.
You need to get an overall concept here of why compartmentalization is important. So I'm trying to give you another example here using this. So...
Transcription and translation is the process through which proteins are made. Transcription happens inside your nucleus. So the first part of making proteins happens inside your nucleus. Translation happens outside in the cytoplasm, this whole bluish area. Now the thing is, this is important.
So we can see our nucleus is compartmentalized. It's an organelle, it is compartmentalized, separated from the cytoplasm. It's got its own little things going on in here. separate from the things going on in the cytoplasm. So this is important.
Compartmentalization here is important because it allows transcription and translation to happen smoothly. Because you know transcription is the first part and it's going to happen here in the nucleus. Now the second part is going to happen in the cytoplasm.
So the problem is, if the nucleus was not compartmentalized, it would be very hard to separate these two processes and they would want to happen at once. And that would be a mess. So this compartmentalization is very cool, very efficient, because it allows transcription to finish first and then translation to happen.
Because something will be made here, it will be sent into the cytoplasm, and then translation will happen. So this compartmentalization is cool, very important, because it separates, it allows these two processes to be separated. If there was no compartmentalization, we wouldn't be able to separate them. And we wouldn't be able to make this one happen first and then this one.
Everything would happen at the same time and it would be a mess. Okay. So just understand that this is an example of why compartmentalization is useful.
Okay. Here, I forgot to show this just now. So I'm going to show you now.
So remember, DNA is like an instruction manual and it codes for a protein. Okay. A protein.
So your body will read this instruction manual and make a protein from it. A final product, so to speak. So here is the same thing. But in real science, you...
Your cell will use the DNA and this ribosome will use this DNA to make a protein. Okay, just like this example up here. Okay, so here. Here basically is the word form of what I just said.
So the fact that the nucleus is compartmentalized allows the processes of transcription and translation to be separated. This allows less interference and more efficient. Just like the school example that I just used for efficient to explain the efficiency of compartmentalization.
Isn't this interesting? This font is kind of cool. I like it.
But look, for some reason, the full stops and the commas are so low that I cannot get over that. A little bit annoying because it's such a nice font, but why do this to me? Okay, so now we just went over. Okay, so I just want to recap. We just went over the two very important parts of this video.
We know that there are two big categories of self. prokaryotes and eukaryotes. And we know the key difference is the fact that eukaryotes are compartmentalized into organelles, which is prokaryotes do not.
And we saw that this is important. Compartmentalization is important for these three reasons. Okay.
For these are three reasons. There are probably more reasons. So just know these three reasons. And you need to remember that these three are not organelles.
Okay. Remember that this might be a multiple choice question or something. Okay.
But don't get too fussed on understanding it because the different sources say different things. Okay, and then we saw this little real example of why compartmentalization is useful. But don't worry about transcription translation. It's a whole other ballgame.
It's a whole other video. Don't worry about it. Just understand the overall concept here of compartmentalization. Okay, now we're getting into the last part.
Before we do some questions, it's also in this chapter. It's called tools for research. So the...
You need to know four key kind of tools that are used a lot in science, okay? And you need to know very little information on them. So don't worry too much So we're just gonna give you a very vague overview in other chapters We're gonna look at them in more detail on some of them. So just know vaguely what they're for and that's enough Okay, so first one microscope.
So you guys should know this one already Hopefully there are many kinds of microscopes light microscope electron microscope and we talked about this one in much more detail in another video So like you'll see Right now we have to mention all four, but you're going to learn about each of these in another chapter in much more detail. So don't worry, just get the overall concept. So we know there are tools used to magnify, making things look bigger than they are, right?
Good for looking at cells, little structures, whatever, many things. Now next one, let's look which ones we look at next. Let's look at this one centrifugation. Okay, so this one's cool Look at this image here first a centrifuge is a little machine here that is basically Very good at spinning.
It just spins things around very very fast. So for example, what's the point of centrifugation? Um, you have a little sample say you have a little sample and in the sample you have a lot of things um a lot of different things amino acids or let's just say there's cells in here.
I mean, those cells have organelles and all that. And what you want to do is separate your cell into its different components. You want to separate the organelles from your cell because you want to look at the nucleus. So what you're going to do is you put your sample in here.
So here's a bunch of cells. And then you put a little thing in there that's going to break apart the cell wall or the plasma membrane so that all the organelles are free. And then you put it into this machine.
This machine is going to spin it really fast. and it's going to separate the components. All the heaviest components, which are normally organelles, will go to the bottom and then things that are lighter like cytoplasm and things like that will be higher. So this technique, centrifugation, is a technique that is used to separate things based on weight and size because the heaviest things will go to the bottom and the biggest things will go to the bottom and the lighter and smaller things will be on top after you spin the hell out of it.
Okay, so here's the words for that. It's a method, all of these three, centrifugation, gel electrophoresis, chromatography, they're all ways to separate things. They're all ways used to separate things but they work a bit differently. Microscopes is the only one that doesn't do separation, just looks.
Okay so here's the little words that used this to describe that. Let's look at chromatography because I think this is one you guys probably know already. So if you have a little, give me a sec, if you have a little, you know, how it works basically is you have a little paper you see a paper here um and then you have a little um you dip it what happens is here's the wooden part which the paper is attached to it's hanging you can see it's hanging down and here you have a little um solvent or like water or something that you dip it into and you know when you dip paper into water the water is going to start climbing up right up the paper and move up right so how this techniques works is you put your sample here Your sample that you want to separate, for example, there could be amino acids, carbohydrates, and you want to separate them. You want to separate the amino acids from the carbohydrates so you can analyze them further or use them for something else, right?
You don't want everything, you just want the amino acids. So you put your sample here and you dip it in this water. The water is going to start creeping up, creeping up.
And the thing is, we know amino acids, proteins, carbohydrates, they're all a bit different in their solubility. So the things that are most soluble in the water. will travel the highest.
The water will keep moving up and those things that love water will travel very high and go to the very top. Whereas those things that don't like water will just stay here. They will move up very little bit.
The water will drag them up a very little bit because they're not that soluble. So this method likes to separate things based on size and solubility. So bigger molecules, bigger heavier molecules will travel a shorter distance and those that are very soluble will travel a very long high distance, right? So this is an interesting method.
So for example, let's say we dip it in the water and we see what happens. Okay, this will happen. So we can see here after some time the water started creeping up and we can see that this sample was separated into four different components, all right?
The component here up high was the most soluble and the lightest was able to move the highest and this one down here would be the heaviest or the biggest. And it would be not that soluble. It wouldn't move that high. Okay, so that's chromatography So centrifugation separates them based on spinning them into the heaviest at the bottom The densest at the bottom and the biggest at the bottom whereas chromatography separates them based on this water solubility Okay, last one here gel electrophoresis.
This is super super cool So this one primarily likes to separate the DNA or nucleic acids. Okay nucleic acids. So for example I'll give you a real-life example of how this is used. Here's the machine.
You've got a little thing here that you turn on and off, okay? And this thing connects to this little thing here. There's a positive end and there's a negative electrode.
So a positive electrode, negative electrodes. When you turn this machine on, that electrode turns on and that one turns on. And then what you do is you notice here, there's like these little slits here.
And in each of these slits, this whole thing is gel, by the way. That's why they call it gel electrophoresis, because it's gel. this substance is gel-like, and electro because we're using electrodes, positive and negative electrode, and foresis means to migrate. So we're using a gel electron, um, um, electric by positive and negative electrodes to make these DNA migrate and separate across this, this gel, this gel surface. So for example, if we have, um, Ronaldo here, John Wick, Donnie Bravo, and, and a wanted person, so these are our three suspects.
We believe one of these three committed the crime, okay, and here We found a sample from the crime scene and we're putting it in here and we're going to try and see who was the murderer Is it John wick? Is it Johnny Bravo or Ronaldo? So what this thing is going to do is once you put your DNA in there, it's going to separate it So the your DNA is going to travel towards this positive electrode But it's going to separate.
So some pieces of your DNA will stop here, some will stop there, some will stop all the way down there. They'll separate into different pieces. And this is the reason why it will separate differently for different people is because different people's DNA are slightly different.
So Ronaldo's DNA, when you separate it using gel electrophoresis, will maybe look like this. And John Wick's will look like this, right? So maybe John Wick had a piece of DNA that separated very far. Okay, and Johnny Bravo had one that only moved to here. Okay, so that's very important.
So different people will separate, DNA will separate differently using gel electrophoresis. So let's say we turn the machine on and this is the results we get. Now, the wanted person, I wonder, so let's, and then we put the sample DNA from the crime scene, we put it in there and we see what happens.
Oh, look, it's separated. Whose DNA does it look most like? It looks exactly like John Wick's. So this way we can prove that the sample of DNA found at the crime scene matches John Wick's, meaning John Wick was at the crime scene.
He was the murderer. So that's really cool, right? So gel electrophoresis separates things based on, separates things, especially it can happen with proteins and stuff like that as well.
But most commonly it's used for nucleic acid DNA for this scenario here, for paternity testing or testing who was at the crime scene and all that sort of stuff. So how this one works is based off charge. So it separates things in a gel using an electrical charge.
So the molecule that is for example, the most negatively charged will move the closest to the positive electrode and all that sort of stuff. Okay? So overall we got microscopes.
We got these three ways centrifugation, gel electrophoresis and chromatography. All of these like to separate things Through some way centrifugation likes to separate based on using a centrifuge chromatography based on the solvent that separates them and then gel electrophoresis uses electrical charge To separate these things. I want you to just understand the big idea the big concept of how these things work Don't go ham on understanding the exact mechanism behind them I want you to understand the big idea because these tools are used a lot in science Okay use a lot in research to do things so it's a very good time now to understand the big idea of how these things work because you're going to see them more in more detail in later chapters so don't go too ham on them.
Okay let's just do some questions. So we nailed now down compartmentalization and organelles and we looked at some tools for research so let's look now at some questions. In eukaryotic cells which organelle is responsible for the breakdown of cellular waste and cellular digestion highlighting the concept of cellular compartmentalization.
We looked at that right it's the lysosome. The lysosome is the thing that breaks everything down. It is the trash can of this cell. Very important to be compartmentalized, otherwise the enzymes will destroy everything else from the cell.
Great. Why is cellular compartmentalization important in eukaryotic cells? It helps maintain a rigid cell structure.
No, it doesn't, right? That's not the purpose of compartmentalization. It allows for efficient cellular communication. No, it's not related with communication. That would be the receptor.
and things on the plasma membrane, right? If you look at the cell, things that allow communication between different cells would be things on the plasma membrane, like little carbohydrates or little proteins that contact other cells, not compartmentalization. It enables for segregation of incompatible chemical reactions. That sounds right, right?
We know the compartmentalization separates all of these different chemical reactions. The chemical reactions of the mitochondria are separated. from those of the lysosome and from those of the cytoplasm. All these different chemical reactions are separated.
Okay good, so it's going to be C. It's not D because it does not increase the size of the cell. It's not related to that.
Okay so it's going to be C. Which of the following cellular structures is not classified as an organelle in eukaryotic cells? So remember the IV wants you to know three.
Okay the cell wall, what else do you remember? These three cell wall cytoskeletal cytoskeleton and cytoplasm. Okay, these three are not organelles So we can see here the answer will be D. Okay last one here. How does cellular compartmentalization?
Contribute to the efficiency and regulation of biochemical reactions within a eukaryotic cells by preventing any chemical reactions from occurring. No Compartmentalization does not prevent Reactions or things from occurring it just separates them into different compartments. They're still going to occur but just in their own little room in their own little compartment okay so by isolating different reactions and processes in specialized organelles. Yes, that's what it does. Compartmentalization will isolate all these chemical reactions, not prevent them from happening, just isolate them into different compartments.
So it's probably going to be B. By promoting uncontrolled mixing of cell components. No, that's exactly what we're trying to avoid.
We don't want all these different enzymes and components to mix together. We don't want chaos. We want organized.
We don't want chaos. We want order. This compartmentalization will organize and prevent uncontrolled mixing of these cellular components Okay d by increasing the rate of random collision between molecules. No, it does not it's not related to that So the answer here will be b so I hope that was useful I hope you learned something in this video and I will see you in the next one