Organelles of the Cell (updated)

okay so in this video we're going to go over some of the common organelles of a eukaryotic cell now an organelle is simply a word that means small part so just like the body has small parts called organs cells have small parts called organelles well there's a lot of them so let's go ahead and get started first thing I want to mention are the three basic sections to the cell and all cells need to take in food get rid of waste and reproduce well cells have three main sections to them and inside of those three sections are parts that allow them to take in food get rid of waste and reproduce so the first section you can see highlighted by the flashing black line the plasma membrane you might also hear the plasma membrane simply called the cell membrane we'll talk more about this in a little bit pulsing in the picture you can see the second main section the nucleus you often hear the nucleus called the control center we'll explain why in a little bit and lastly we have the cytoplasm now the arrow in the picture looks like it's kind of just pointing to empty space well cells are not filled with empty space they're filled with a part called the cytoplasm we'll go into that in more detail let's actually do the cytoplasm first here we go so the cytoplasm the first thing I want to mention is that it's the jelly-like material on the inside of the cell you know when you look at diagrams sometimes in a diagram a cell might look like it's empty or filled with hollow air hallow airspace and that's not true cells are filled with a jelly-like liquidy material called the cytoplasm and in that cytoplasm most organelles float with it you can see here's a list of a few of the organelles that are floating around in the cytoplasm we're going to go and talk about all of these throughout this video we'll talk about what the mitochondria is what lysosomes are and because the cytoplasm is a jelly-like material and things are floating around inside of it you often under a microscope can actually see parts floating around in this animation here you can see what's known as cytoplasmic streaming the green circles that are drifting around inside of the square cells the rectangular shaped cells those green circles are plant cell chloroplasts you can see in every rectangular shaped plant cell there's a few dozen chloroplasts yeah in in each of these cells here this is known as cytoplasmic streaming okay well what about the job what does the cytoplasm actually do well a lot of chemical reactions take place within the cell and chemical reactions take place in the cytoplasm so that's kind of what the job of the cytoplasm is it helps to facilitate chemical reactions and it also helps to dissolve solutes particles that are in the cell carbohydrates proteins these are all dissolved within the actual cytoplasm of the cell so that's really what the main function of the cytoplasm is it also adds support to the cell a pressure support for the cell so the next part I want to mention is called the plasma membrane also known as the cell membrane and first of all it's composition means what is it made from it's a bilayer of lipids and proteins earlier in the school year we learned about lipids lipids a pit here the round part represents the head two tails are the fatty acids and what we mean by a bilayer it's not just one layer but two layers on top of one another this is a bilayer of lipids right here in between the bilayer of lipids are also proteins I've labeled this protein channel and you're going to see its importance in a moment well the job of the plasma membrane is to allow materials to to pass to enter an exit you know small molecules like water and oxygen h2o for water Oh two for oxygen small molecules like this can simply pass through the lipid bilayer however larger molecules larger molecules like glucose have to pass through these protein channels and that's what you see happening in the animation and so that's really the job of the cell membrane but the cell membrane is what we call semipermeable or selectively permeable that means that it doesn't allow everything in and out it only allows certain specific molecules and ions and and charged particles to enter or exit through the plasma membrane so when we come back to this picture we saw earlier here we have the next part I want to mention you can see the black square highlighting the nucleus let's zoom on in for a closer look when we zoom on in here we have the nucleus and you've heard maybe in middle school that the job of the nucleus is to control the cell's activity you often hear given the nickname of the headquarters well what does that mean well the reason we call the nucleus the headquarters is because it contains DNA and in the picture we see five twisted strands of quarters called chromatin chromatin are long strands of DNA and DNA is the instructions the blueprint the manual on how to make proteins this is why we call the nucleus the control center is because the chromatin will be sending out information to make proteins and proteins do a lot of the work the vast majority of the work inside of our cells inside of our bodies are performed by proteins so this is why the nucleus gets the nickname of the control center also inside the nucleus there's a round object known as the nucleolus and the job of the nucleolus is to make another part of a cell another organelle called the might excuse me called the ribosome so the job of the nucleolus is to make ribosomes and we're going to see what ribosomes do in just a moment when we look at this picture right here we can see a nice electron microscope picture the overall round object is the nucleus you can see the dark spot is the nucleolus a really nice picture here of the nucleus and the nucleolus so we come back here we have the box highlighting the rough ER and the smooth ER let's zoom on in and take a closer look at the endoplasmic reticulum okay first of all there's two kinds of ER let's look at the rough ER first the ER stands for endoplasmic reticulum the rough ER the reason it's called rough is that's covered in ribosomes so we mentioned a moment ago that the nucleolus makes ribosomes the ribosomes then exit the nucleus and travel along this tunnel system known as the rough ER that's kind of the job of the rough ER is to receive the ribosomes and transporting and carry around the ribosomes from one part of the cell to another as you can see we can we finally see what the job of a ribosome is protein making ribosomes so that's the job of a ribosome is to make a protein so the rough ER will transport the ribosomes as the ribosomes are making a protein well if we look at this picture here we have the purple nucleus identify part a in the nucleus I hope you know that the nucleolus the the lines the purple lines identified by letter B that's the DNA I hope you remember the name of the DNA that's called chromatin and then the outside of the nucleus in pictures see I never mentioned the name earlier but that's called the nuclear envelope notice how the blue is the rough ER and there's gray dots all over it well look in the animation you see grey dots exiting the nucleolus and the animation and those gray dots are traveling through the blue rough ER that means those gray dots have to be the ribosomes the job of ribosomes are to make proteins we're going to go into more on that in just a few moments so what about the smooth ER well if the rough ER is covered in ribosomes then a little common sense the smooth ER is not covered in ribosomes and you can see it has a different job the job of the smooth ER is to help make lipids and fats and to help break down certain toxins but the reason it gets its name smooth ER is it's not covered in ribosomes the rough ER is covered in ribosomes and that's why it kind of has a rough appearance to it so let's talk a few moment a few extra moments about those things called ribosomes they're created by the nucleolus remember the nucleolus is inside the nucleus they're transported the ribosomes are transported by the rough ER and as the ribosomes are being transported by the rough ER we now come to their job their duty their function is to make proteins and so if we highlight a few a few ribosomes with that flashing black box let's zoom on into a ribosome that's attached to the rough ER well here we have a ribosome and the reason what what I mentioned a moment ago is its job is to make a protein and what does is it will gather individual amino acids and earlier in the school year I hope you learn you remember that amino acids are the building blocks of proteins and so here we see a ribosome is gathering and connecting a bunch of amino acids into a long chain this long chain of amino acids is what we call a protein that's the job of a ribosome is to gather and build these amino acids into a larger protein this process by the way is known as translation we're going to learn about it later in the school year though so if we come back out here to our diagram I've highlighted the flashing box of the Golgi body let's zoom on in to the Golgi body you might often hear it called the Golgi apparatus or the Golgi complex it's always going to be called Golgi because it's named after the scientist with the last name of Golgi who discovered it and so the job of the Golgi body is to receive proteins that ribosomes made receive proteins for that ribosomes made modify them sort them and packaged them so they can be exported from the cell and the Golgi body will put the proteins into a protective little envelope known as a vesicle and so let's go ahead and review what we've learned really quick when we look at the process of shipping out of protein in our animation we can see the nucleolus is releasing a black dot that black dot represents right a ribosome so the nucleolus makes a ribosome notice that ribosome then travels through that rough ER that system of tubes and tunnels so the ribosome is traveling through the rough ER making a protein let's zoom on in for a closer look so there's the ribosome okay now that we can see the ribosome remember what the job of a ribosome is it meant it makes a protein and so there you see the word protein now it's spelled PR OT ein but it's not really put together properly so this protein is not quite finished even though the ribosome made it watch what happens next remember this is all happening at the rough ER the protein is going to be placed inside of a protective vesicle and travel away where is it going I hope you know where it's going it's going to a Golgi body and so the protein arrives at the Golgi body what happens to the vesicle the vesicle fuses and becomes a part of the Golgi body well watch what happens the protein moves through the Golgi body and is eventually processed and modified and ultimately is going to be released so the Golgi body kind of makes the final changes to the protein well when the Golgi body releases the protein it also will put it in a protective vesicle so the vesicle is going to be a protected little envelope watch this the protein is put into a protective vesicle and it's released the vesicle fuses with the cell membrane and then the protein is simply released from the cell goes where it's needed all right so if we were in class I would have you turn to your neighbor and try to work on these review questions so we've kind of covered a lot of information let's take a quick moment you know pause the video pause the video try to answer these seven questions I'm going to go over the answers in three two one so which organelle builds proteins I hope you know that's a ribosome which organelles stores DNA well that's that's the control center called the nucleus which organelle produces ribosomes that's the nucleolus it's found inside the nucleus which organelle creates fats and breaks down toxins well that's the smooth ER which organelle number five packages and releases proteins from a cell that's the Golgi body remember they're put inside of a protective vesicle number six which organelle allows materials to enter an exit a cell that's the cell membrane also called the plasma membrane number seven which organelle links chains of amino acids together that's the same thing as question number one question number one and question number seven it's the same question just word it a little differently because amino acids make proteins let's try this one same thing in class I would have you work on this with the neighbor for a minute but pause the video try to put these four steps in order what comes first second third fourth I'm going to show the answer in three two one okay so the answer is I hope you chose step C first the nucleolus makes ribosomes and then I hope you chose D ribosomes will exit the nucleus and then I hope you chose B the ribosomes are going to travel along the rough ER and create proteins and then finally I hope you chose a the Golgi body will package and export the finished protein inside of a protective vesicle let's move on so now we're back to our diagram and I've highlighted the flashing box the mitochondria let's zoom on in for a closer look here we have the mitochondria artist drawing on top actual picture on the bottom and so the job of the mitochondria you know in middle school they give cute little nicknames to sell parts in middle school you may have been told this is the power house but you may never have been told why well it's the power house because its job is to make an energy molecule by the name of adenosine triphosphate ATP so the mitochondria does a very important process known as cellular respiration and during the process of cellular respiration it will create an an energy molecule by the name of ATP ATP is a molecule used by your cells for energy so the analogy is the mitochondria is kind of like the battery of your cells what's interesting about the mitochondria is we're pretty certain the mitochondria used to be a living organism it used to be a basically a bacterial cell but it has become part of today's modern cells and this theory of of how we think this happened is called endosymbiosis I'll go over in more detail in just a moment well when we look at some of the evidence for why we think the mitochondria used to be its own living organism is because it has its own DNA it has its own ribosomes because it has its own ribosomes it can manufacture its own proteins and the mitochondria does something very important to life the mitochondria can reproduce and replicate so when you look at this evidence it's pretty certa pretty certain the mitochondria used to be a free living organism a bacterial species but it's become part of cells how did that happen that's what endosymbiosis tries to explain I hope I can visualize that on the next slide okay so I really want to try to visualize the endosymbiosis theory here we have a large predator sell an orange that's going to devour that red mitochondria ancestor watch the watch this so there it goes it just devoured the mitochondria ancestor but the way we think it were had happened is that red mitochondria survives and divided and multiplied it's just trapped inside of the large predator cell well as the two go about their lives the large predator cell eventually is going to multiply and divide as well and watch this when cells divide they often grow and then they split right down the middle and now you have two cells two cells with the mitochondria ancestors trapped inside of them and then the process simply continues so the the mitochondria ancestors keep multiplying and then the orange predator cell divides in half and over time over millions and millions of years the two have become so dependent on one another that they can't survive without them so this is kind of what the what the endosymbiosis theory it tries to explain is how cells became more complex how did we obtain certain cell parts and this is a the explanation for how we think the mitochondria was obtained okay let's zoom on in let's focus on the lysosomes back in our diagram here let's zoom on in for a closer look at the lysosomes and so the lysosomes contain inside of them very powerful digestive enzymes and that's my little animated scissors here are showing so the blue circle is the lysosome with the animated scissors representing the enzymes inside and so lysosomes have various jobs number one is to break down food so here we have a protein molecule that's being taken into the cell and the protein is being broken down into smaller parts hope you know those smaller parts are called amino acids here we have an example of a white blood cell you probably know white blood cells job is to fight off infections like bacteria and viruses well that's what we call pathogens things that cause disease are called pathogens and so here is a virus or a bacteria and and notice how it just landed on a white blood cell well what happens is the white blood cell will swallow up that pathogen put it inside of a lysosome and those powerful digestive enzymes will destroy it that's one way that our immune system keeps us healthy and then there's the process called autolysis where it's basically an aging cell will destroy itself and so in our in the middle of our picture here we have a group of cells and I have the animated scissors because what happens is when cells are dying and aging they will kind of self-destruct in a process called autolysis where the lysosomes will release all the digestive enzymes and kill that cell it leaves behind a gap but don't worry that gap will simply be filled in as cells multiply so you've heard the expression out with the old in with the new a couple other cell parts I want to mention are used in movement and that's the job of cilia and flagella now not all cells move so not all cells have cilia and flagella but if cells move they probably have either cilia or flagella so the picture on the left shows the cilia short hair like extensions there's numerous hundreds and thousands of them per cell wait a minute account very short stubby almost look like eyelashes they're so short and stubby the picture on the right shows a sperm cell with a real long flagella flagella is actually the plural version flagellum is singular and so the difference is really their length the cilia short stubby flagella are long and whip-like and usually there's only a few of them may be only one flagellum maybe two maybe three maybe four but not nearly as many as the cilia well in that picture on the right we have a sperm cell about to penetrate a female egg cell to create a fertilized egg also known as a zygote let's have a little fun with this so after the fertilizer the sperm fertilizes the egg that fertilized egg is going to grow into a fetus here we have a nice little ultrasound showing a child growing inside of a pregnant woman well eventually nine months later that child's going to be born well let's follow the life of this child 17 years go by 17 years later hey it's your first day at high school and so here you go welcome to high school and hopefully four years after that you know you'll be celebrating your graduation from high school so this all started because of that flagella that provided the swimming movement to fertilize an egg so we look at the next part I want to mention is the cell wall and so this is the outermost layer of plants fungus and bacterial cells so from left to right we have plans fungi and bacteria notice animals like humans do not have a cell wall well we also mentioned that the cell wall is the outermost layer so when we look at this picture we have a yellow layer and a green layer so I hope you know that yellow layer represents the plasma membrane or the cell membrane and the definition in the definition we see that the outermost layer is the cell wall so that's represented by the green layer what about its job one of the jobs of the cell wall is to add support it's made from a real tough sturdy material known as cellulose and so this adds some of the support to plants and fungus and bacterial cells that have and so as I just mentioned the cell walls made from a real tough material by the name of cellulose it's very hard to digest the reason for the picture is celery has a lot of cellulose in it and I'm sure you've had bites of celery it's a very tough very fibrous plant very hard to digest that's because you're having to chew through a lot of cellulose which is a main ingredient of the cell wall and the cell wall really started our understanding of cells earlier in another video we learned that Robert Hooke in 1665 again there's really there's no real good pictures of Robert Hooke so could we just have a glass stained glass picture in a Cathedral Robert Hooke in 1665 examined cork and so he used a very primitive microscope like this one in this picture here and as I mentioned a moment ago he examined cork now cork we might be familiar with cork from you know wine bottles but cork is actually tree bark and he examined a real thin slice of tree bark called cork and this is what he saw in this picture here it is a drawing that he made kind of a shocking to believe that this picture right here is a drawing made by hand but that's how good of an artist he was and what you see are hundreds of little tiny cells but the outline of the cell is all that's left he did a drawing of the cell wall there was no nucleus cork and tree bark is dead there was no nucleus when he made the drawing there were no mitochondria no vacuoles all that's left and all you can see in the picture is the drawing of the cell wall the cell wall is very tough very strong and can last for years and years after the cells have died so the next part I want to mention is called the chloroplasts and so you might know the job of the chloroplast is per is to perform photosynthesis well here are several dozen plant cells taken with a microscope let's zoom on in for a closer look when we zoom on in we can see that inside of every cell are dozens of those green round shaped objects called chloroplasts they're inside every single cell there's dozens of them per cell so you know that the job of the chloroplast is to perform photosynthesis well inside of the chloroplast is a chemical a green chemical by the name of chlorophyll the job of chlorophyll is to actually perform photosynthesis it will absorb sunlight absorb carbon dioxide absorb water and turn those into oxygen and sugar particularly in the form of glucose so what photosynthesis does is it uses three ingredients water carbon dioxide sunlight and we'll release two products oxygen and sugar sugar called glucose just like the mitochondria the chloroplast is thought to have evolved according and become a cell part according to the endosymbiosis theory we think the chloroplast was also a free living organism of bacteria in our animation here we have a predator cell devouring the chloroplast but not really being digested that chloroplast ancestor in green multiplies just like we saw a moment to go with the mitochondria ancestors and notice how the two are just living together the green chloroplast ancestors are just trapped inside of the larger one well as time goes by the largest cell divides and splits into two and as years and go by these two have become so dependent on one another that they are now a part of each other and the evidence to support this is again the chloroplasts just like the mitochondria have their own DNA and ribosomes they make their own proteins they can replicate and multiply and divide these are all real strong indicators that the chloroplasts were probably once a free living organism all by itself but has become taken into the cell and become part of modern cells so the final one the last part I want to mention is called the vacuole the job of the vacuole is to store food store water waste color pigments and in the picture here you can see it's the big blue round object in the middle of the cell often in plants that is it's often the largest part of a plant cell so in plants it's often the largest central meaning in the middle so we often think of the nucleus being in the middle of a cell often the vacuole is because it's so big it pushes all the other parts to the edges when we look at this little animation right here again I mentioned cytoplasmic streaming earlier here the green circles represent chloroplasts but they're all kind of revolving around the central vacuole and so the central vacuole is often so big it will push the other organelles to the edge of the cell so in plants there tends to be a large central vacuole but it's not like that with animal cells here's a diagram a drawing of animal set of an animal cell and the vacuoles are much smaller and they're usually randomly scattered throughout the cytoplasm but they still serve the same purpose they still store food store water store waste and so that's really the job of the vacuole right there well so there you have it I mean there's a lot of cell parts that we covered in this video here so try and pause the video and work through these questions if you're in my biology class bring your answers to on a separate sheet of paper I'd be happy to check your accuracy either before school or after school good luck

Channel: Beverly Biology

Views: 2,647,272

Rating: 4.8030982 out of 5

Keywords: Cell (Anatomical Structure), Organelle, Stem Cell (Field Of Study), Biology (Media Genre), Ribosome (Literature Subject), Protein (Nutrient)

Id: RKmaq7jPnYM

Length: 29min 51sec (1791 seconds)

Published: Fri Jun 06 2014