Mitochondria Structure & Function

foreign what's up Ninja nerds in this video today we're going to be talking about the structure and function of the mitochondria before we get started if you guys like this video makes sense helps you benefits you please support us well wait can you do that hit that like button comment down the comment section please subscribe also you want some great notes illustrations I really really suggest you guys check them out they're really good we have a great engineer team who compiles them so check them out go down in the description box below take you to

our website where you guys can check those out all right mitochondria it's always referred to as the PowerHouse of the cell right we're going to dig a little bit deeper okay so when we talk about the mitochondria let's first go through the structural components of it and then what we'll do is we'll dig into the function of it step by step kind of not just sticking with the only factors that it produces ATP there are a lot of things that this son of a gun can do all right so the mitochondria first thing is it's

really kind of I'm not even kidding this is the way that they hold in the textbook a sausage shaped uh kind of like organelle inside of the cell and when we look at it and actually zoom in on the structure there's a couple different components that we have to know the first one is that you have this kind of like membrane and it's double layered it has like a outer membrane out here so this is called your outer membrane and again it's made up of a like a phospholipid layer bilayer actually Auto outer membrane big

thing that I kind of want you to take away from the outer membrane is the outer membrane is a very permeable membrane okay so it's a very very permeable membrane highly highly permeable so it's got these big pouring molecules that allow for things to move in and out of the mitochondria one big thing that you may see on your exam all right so here's the outer membrane then if you look here's the other component of it right here you see how we have the outer membrane which is this kind of maroon line and then here

we have another Moon line that's called the inner membrane this is called the inner membrane again another phospholipid bilayer which is pretty cool big thing to take away from this one though is it is not very permeable has a lot of selective proteins Transporters that are present on it that really are very closely regulated and determine what moves in and out of the mitochondria so this one is less permeable really kind of a big just term that I want you guys to take away from these two now there's a space and that exists right between

these two so here was the outer here was the enter there's a little space between these two and this little space here is called the inter membrane space really really cool thing about this one and we'll talk about it later is that it is really really highly concentrated with proton ions which is really really helpful with your electron transport chain so we'll get into that a little bit later all right so we got outer membrane inner membrane inter membrane space which is kind of just a little bit of fluid rich in protons okay we come

into the inner part here so one more thing you see how they have the inner membrane if we were to follow this thing along look how it kind of continues continues and then you get like these like little invaginations that are coming off of the inner membrane that's a really really important thing so what I want to add on here is with the inner membrane so with the inner membrane so with the inner membrane we're going to rewrite it there is a specific type so this kind of invagination is actually called the Christa so it's

a continuation of the inner membrane but invaginates into the center it's all these things here's a Chris Day here's a Christa here's a Chris Day Chris Day Chris Day Chris day okay the whole purpose of these puppies is to increase the surface area for a lot of specific types of metabolic reactions that we'll talk about a little bit later okay so we got outer membrane inner membrane intermembrane space the inner membrane there's a special type of them which invaginates into the actual center of the mitochondria called the Christa which increases the surface area for a

lot of metabolic reactions the last part is all of this kind of white space here which is basically the mitochondrial Matrix so really all of this in here is called your mitochondrial Matrix and it has a bunch of different fluid and solutes in it but two particular things that are really pertinent to The Matrix um the major the mitochondrial Matrix is what's called mitochondrial DNA which is represented right here see these little guys right there that's your mitochondrial DNA it's really cool because this is actually maternal DNA so it's maternal DNA and then the next

part here is not only is their maternal DNA which obviously has some types of genes to uncode to make particular RNA to make proteins but we need certain things that are helpful in making proteins so mitochondrial DNA can make RNA but we need ribosomes to be able to translate that RNA and make proteins and some of these proteins the mitochondria can make on its own to help with its own functions so that's a really really cool thing and we'll get into that a little bit later but this is the big big thing that I want

you to understand so again to recap it this is outer membrane this is inner membrane a special invagination of the inner membrane into the center is called the crestae which one's highly permeable outer which one's less permeable inner what's the space between the outer and the inner membrane the inner membrane space what is it rich in proton ions and then what is all of this fluid here that is in the center of the mitochondria the mitochondrial Matrix rich in mitochondrial DNA and ribosomes the mitochondrion is an organelle that is the PowerHouse for both animal and

plant cells during a process called cellular respiration the mitochondria make ATP molecules that provide the energy for all of the cell's activities cells that need more energy have more mitochondria let's now dig into the function of the mitochondria specifically what I want to talk about is the membranes so we'll get into the Matrix that's next but what I want to talk about first is let's talk a little bit about the outer and the inner membrane and what are some of the functions that this puppy does so let's come down here the first thing that I

want to discuss here is it plays a huge role in protein transport the membranes so what we're doing is we're zooming in this is a cell sorry so this is a cell here this here is the nucleus so this is our nucleus here is a ribosome these are free ribosomes and then I'm just zooming in on the mitochondria so I'm going to represent this as the outer membrane the inter membrane space and the inner membrane and then what would this be this would be the Matrix so I'm just zooming in onto the part of the

mitochondria now the mitochondria has DNA right it has DNA here's like some of that mitochondrial DNA and it can make RNA which can helpful to make some proteins but it doesn't make all the proteins that it needs to be able to function and so sometimes we have to take some of the proteins from the nucleus so the nucleus will help us to make RNA RNA will then make proteins and these proteins have to get sent into the mitochondria and that's really really important so for example here here's our DNA it's going to make mRNA m

r and a that mRNA will then come out via the nuclear pores when it comes out via the nuclear pores here's my mRNA it'll then combine with ribosomes and from this from the ribosomes will then synthesize what proteins but here's the big thing these proteins are unfolded oh there we go it's unfolded therefore it's not Super Active it's not the active form okay so the mitochondria has special Transporters that really are special in moving these unfolded proteins that it needs to be able to perform reactions inside of this the mitochondria it needs to transport it

across so what happens is this protein here will get chaperoned and then we'll bind onto this like little receptor here and there is this outer membrane translocase we literally call them Toms translocase of the outer membrane and what happens is once this unfolded protein binds to the receptor what it'll do is it'll open up this Tom and move this unfolded protein into the inter membrane space and the inter membrane space a little chaperone protein will bind to it and bring it to this next point so it'll bring it to this next receptor on the inner

membrane when it binds here it activates this particular stimulated this receptor stimulated this receptor when it stimulates this receptor it opens up this next channel on the inner membrane this is called Tim I'm not even kidding so translocase of the inner membrane and when that binds onto the receptor it opens up and pushes the unfolded protein into the mitochondrial Matrix in the mitochondrial Matrix we need maybe this protein to perform specific things maybe it's an enzyme that plays a role in a lot of metabolic reactions and I need him and so what happens is you

have specific types of proteases or other enzymes that will then work on this protein and properly fold him together and activate him and make him into a specific special enzyme and now this is a active folded enzyme and it's ready for it to perform its functions inside of the mitochondria and there's so many different proteins that you need and so it's a really really important point because the mitochondrial DNA right the mitochondrial DNA it only makes like 15 of the proteins so really when it goes to make proteins these proteins that it makes is only

15 of what's needed so that means I need a lot of proteins from the nucleus to help me to perform a lot of the functions so that's one of the cool things the mitochondria accepts proteins and they're unfolded form brings them into them and then activates them by folding them properly and then uses those for their metabolic reactions pretty cool right all right that's one of the functions of the membrane let's go on to another one which is a plays a role in like miscellaneous transport and then we'll talk about the Big Mac Daddy function

of the mitochondria that the membrane plays a role in and that is the electron transport chain all right my friend so now next one is it also plays a role so with protein transport is a big one but it plays our own like small miscellaneous things and this may seem like very like straightforward and I I kind of thought that was common sense it is but it's just a quick reminder of things that also a lot of things move across the mitochondrial membrane right and what are those things well I want you to understand and

we're going to get into them a little bit but metabolic reactions they're very very heavily involved in the the mitochondria and so in order for some of these metabolic reactions to occur I have to move things like carbohydrates right across the actual what across the mitochondrial membrane these have to move in and out because you'll talk later that we do a lot of different things like glycolysis has to occur inside of the mitochondrial Matrix or gluconeogenesis has to occur inside of the mitochondrial Matrix right we have to move things like fatty acids so we move

things like fatty acids in here as well because they play a role in something that we'll talk about later called beta oxidation right we have to move things like amino acids in here right because they may play a role in something called the urea cycle and so there's a lot of different things that are actually moving across this cell membrane and that's a really really important point that there's a lot of ions that are moving across ions and small macromolecules that are moving across the mitochondrial membrane very very key and again I think one of

the big things to understand here is if they were to ask you a question regarding the transport of things across the mitochondrial membrane which of the membranes is very permeable outer and which one is very little permeability inner membrane so a big thing to take away okay now we come on to the next component here the next component that I want you guys to understand that is very critical to the function of the mitochondria and oftentimes what it's referred to with that big buzzword term is the PowerHouse of the cell produces ATP ATP is power

energy right so this electron transport chain is huge and it's found primarily on the inner membrane so you don't really see this involved in the outer membrane primarily in our membrane and we're not going to go into crazy detail of all the different processes that are occurring on the electronic transport chain we're going to talk about that in the biochemistry or metabolism playlist if you guys want to go watch that we have a playlist where we go through the electron transportation in depth and we do an overview of it but the basic concept here is

that you have these protein molecules and they make up these different complexes like complex one complex two complex three complex four and a very special molecule called ATP synthase and what happens with these is that they take things you know you have your Krebs cycle and so from your Krebs cycle you take a molecule called pyruvate right pyruvae gets converted into acetyl COA and then acetyl-coa goes through this special thing called the Krebs cycle so this is called your Krebs cycle and from the Krebs cycle which occurs in the mitochondria we form these high energy

electron Transporters called fadh2 and nadhs and they're carrying with them a lot of electrons in the form of like they have them in a hydrogen what's called a hydride ion and what they do is they take and they transport these electrons onto these proteins and they drop the electrons off in them and then these guys pass these electrons down the chain from areas of high energy to areas of low energy and what that does is with each time that that happens it pumps all these protons out into the inter membrane space pumps all these protons

out into the intermembrane space and you guys remember what I told you was very very rich and intermembrane space I said it for a reason it's protons and then these protons what they do is they move from areas of in this situation they move down this ATP synthase and they move down pretty powerfully and what it does is is it moves down this ATP synthase it creates this energy that the protein can Harvest and when it harvests all that energy what it allows it to do is is naturally something is bound to this and it's

called ADP and an inorganic phosphate they're kind of stuck to this this ATP synthase but as the protons run down this gradient as electrons are being passed down it creates this energy that fuses these puppies together and then what it does is it releases it in the form of ATP and this process where we make ATP via the electron transport chain is a very specific type and we call this type of ATP production oxidative phosphorylation phosphorylation so a really really key component here that's happening in this particular inner membrane one side effect though that comes

from these reactions is that all these electrons that are getting passed along the membrane Sometimes some of these electrons that are really really rich out here they can actually combine with things like oxygen and they can combine with other molecules and they can make things like hydrogen peroxide or they can make superoxide free radicals so they basically can increase the formation of things called reactive oxygen species which is that unfortunate side reaction from the electron transport chain that's something that can happen as a side reaction of the electron transport chain so again three functions to

take away from the inner and outer membrane outer membrane highly permeable inner membrane less permeable they allow for miscellaneous things to travel in and out of the mitochondria specifically for metabolic reactions things like carbohydrates things like amino acids things like fatty acids and we'll talk about those reactions in a second they also allow for unfolded proteins that are made by the nucleus by ribosomes in the cytoplasm to be transported into the mitochondria so that they can use them for their functions they don't make all the proteins that they need they really only make like 15

of the proteins and enzymes that they need so they need a lot of proteins from from the actual nucleus and the last thing is they have the electron transport chain specifically on the inner membrane and what does it do it takes high energy electrons from nadhs fadh2s which are generated from metabolic reactions passes it on to those things they pass the electrons down this chain and pump protons into the inter membrane space and then allows for it to flow back down into the mitochondrial Matrix harvesting energy to make ATP via oxidative phosphorylation then an unfortunate

side reaction that can occur from the electron transport chain is you can make reactive oxygen species unfortunately all right my friends let's now go into a little bit more detail of what are these reactions that occur in the mitochondrial Matrix we've like clipped off a few of these like okay there's you know the Krebs cycle there's gluconeogenesis I already said those terms there's the urea cycle there's fatty acid oxidation some of these things that I've said we're going to kind of quickly go over them and talk about how they're involved particularly in the mitochondrial Matrix

so that if you're asked which of the following reactions occur in the mitochondrial Matrix and you'll see this when we get into biochemistry you can pick out which one it is likely that's going to be occurring there all right and then we'll briefly talk finishing about mitochondrial DNA and we'll talk about ribosomes let's get over there and talk about that all right guys so now we're going to talk about the next component here which is the functions involved in the mitochondrial Matrix so we went over the inner membrane and outer membrane how they're particularly involved

in things like protein transport miscellaneous transport of things like nutrients as well as some ions and on top of that we went over the electron on transport chain a really really big function for ATP production via oxidative phosphorylation well the Matrix really what's cool about this is that we already kind of gave a little leeway or kind of like introduced this slightly that there's a lot of metabolic reactions that can occur in the mitochondria so really what I'm looking at inside of this red membrane here can pretend that this is the combination of the inner

outer membrane and the inter membrane space this is just the entire mitochondrial membrane here and then in this is going to be your mitochondrial Matrix and that here is going to be your cytoplasm inside of the cell so this is all cell but we're just zooming in on the mitochondria particularly The Matrix inside there and then the cytoplasm all out here okay so what's cool is you know whenever you take something like glucose so you bring glucose into the cell right so let's say that you bring glucose into the cell what we know is that

once glucose gets into the cell it eventually gets converted into something called pyruvate via glycolysis and then that pyruvate will get brought in to the actual mitochondria when pyruvate is brought into the mitochondria it then undergoes a conversion into a specific molecule called acetyl COA and then acetyl-coa will go through these series of like steps which I don't want to talk about every single substrate we'll do that later in Biochemistry but this process where it goes through this cycle is called the Krebs cycle and so what you're seeing is two particular reactions that are occurring

here so far one is you're seeing the conversion of pyruvate into acetyl COA and the second thing you're seeing is the Krebs cycle and we already briefly talked that coming off of the Krebs cycle is those high energy molecules that carry electrons called nadhn fadh2 and these go to the electron transport chain where they pass off those electrons pump protons into the inter membrane space and they help to generate something called ATP via oxidative phosphorylation well what's another reaction that can occur here there's another cool one you know whenever we take something like fatty acids

so fatty acids these are just long chains like sometimes these suckers can be like 16 carbons long we can bring these in to the mitochondrial Matrix across the membrane so that's another example of Transport across that and then they can go through these series of metabolic reactions where they get broken down into acetic OA and then you can use them to make energy this step here is called beta oxidation this is another one of the reactions that takes place inside of the mitochondria Matrix so so far we have the conversion of pyruvate into acetyl COA

the Krebs cycle and then beta oxidation of fatty acids what else can occur here there's another really cool one you know when you take something like amino acids amino acids can get brought into the mitochondria as well and what happens is amino acids eventually they can get metabolized into something called ammonia right so they can actually get metabolized and when they get metabolized they give way to products in the Krebs cycle we're not going to mention which ones but when it does do that it can give off something called ammonia and ammonia is really really

toxic really nasty son of a gun that you don't want to have to deal with so what happens is ammonia will go through these like series of reactions here and it's called the urea cycle and what happens is it liberates this molecule called urea Which is less toxic in comparison to the ammonia and it's easier to be excreted but this cycle here this cycle that occurs kind of in the What specifically in the mitochondrion even a little bit if you notice over here even a little bit of the cytoplasm What's this called This is called

the urea cycle so this is called the urea cycle that's another metabolic reaction that takes place where in the mitochondrial Matrix another one another reaction that's really cool is I can take something like amino acids I can take something like odd chain fatty acids and I can convert them into specific substrates but then what I can do which I'm going to represent here with a let's do it with a pink Arrow is I can convert them back into pyruvate and then back into glucose you know what this is called when you take something like an

amino acid and not chain fatty acids and make glucose from it it's called gluconeogenesis so that's another reaction which I'm going to represent kind of going in this with the Pink Arrow so I'll represent it right here as the fifth reaction this is called gluconeogenesis okay so that's another one and then there's one more reaction from the Krebs cycle you can take some of these intermediates and make something called heme and some of these molecules of heme are actually synthesized in two places they can actually be synthesized in both the mitochondrial Matrix and they can

be synthesized in the cytoplasm so both of these so we can make something called heme there's another reaction so what's that one that's the sixth one so what I'm trying to tell you here is there are so many metabolic reactions that take place within the mitochondrial Matrix what are some of them if we were to again recap them we call these reactions first one is pyruvate to acetyl-coa that's one particular reaction the second one that is also really important here is the Krebs cycle that's another particular reaction Krebs cycle the third type of reaction here

that also occurs is going to be and I actually made it a two but that should be a three I apologize this is beta oxidation so this is breaking down fatty acids so the third one should be beta oxidation of fatty acids so we'll put beta oxidation there's actually another one here so we go three we go four this is the urea cycle so this is the urea cycle but another big thing that I want to add on here is that urea cycle can occur in two places as you're noticing by this reaction it can

occur in the mitochondria but it can also occur where and the cytoplasm another particular reactions beside this one as we go to Five is this involved in what's called gluconeogenesis this is called gluco neogenesis and what is gluconeogenesis it's taking something like amino acids or taking something like odd chain fatty acids and converting them back into glucose but did you notice that this one also takes place in the mitochondria and it also takes place in the cytoplasm another particular reaction is taking something like Krebs cycle intermediates and making heme and it's involved in two particular

places where it's involved in the mitochondria and in the cytoplasm so that's another particular reaction which is heme synthesis heme synthesis and again we can find this in two particular places both the mitochondria and the cytoplasm usually to remember these combo I remember hug heme synthesis urea cycle and gluconeogenesis as a little mnemonic there is technically one last one if you really wanted to remember I could take acetyl coase and I could shunt them into making something called ketones and that would be the last particular reaction that could occur inside of the mitochondrial Matrix would

be something called keto Genesis ketogenesis so you can see there is a lot of metabolic reactions that take place inside of the mitochondria a massive amount it's insane I don't expect you to remember every single one of these steps here the big thing I want you to understand is that the mitochondria is involved in a ton of metabolic reactions that if you try and remember this now it'll be helpful whenever we get into biochemistry and you'll see a lot of these reactions take place over and over and over again that we'll go over all right

so this is the big thing I want you to take away from this aspect of the mitochondrial Matrix let's come down and talk about a couple more things with the mitochondria so so far we got protein transport miscellaneous transport electron transport chain we got a lot of metabolic reactions seven of them with three of them hug hug heme synthesis urea cycle and gluconeogenesis occurring in both the mitochondria and cytoplasm the last thing is that this son of a gun can be involved in apoptosis it's actually pretty crazy I'm not going to go too crazy with

this we'll talk about a more detailed cell pathology but whenever there's some type of process where a cell is infected or is cancerous or it needs to die unfortunately it has to die there's special molecules present called cytochrome C and it's located inside of the mitochondrial Matrix now naturally we don't want these things to be leaking out so there's proteins called like bcl2 that really help to prevent this from occurring but what happens is in apoptosis you decrease the number of these and so now we can't control these cytochrome molecules from leaking out and the

cytochrome C molecules which is supposed to be kept in the mitochondrial Matrix leaks out and these are nasty molecules because what they do is these cytochrome C molecules they activate these enzymes called caspases and these are basically proteases and they just start ripping through a bunch of different cells and so they start just damaging cell membrane damaging organelles and eventually cause the cell to undergo its death process okay so it'll lead to a lot of signaling process that will trigger it's programmed cell death that's what apoptosis is it's programmed cell death okay my friends let's

move on to the last particular function here for mitochondria and that's pertaining to the DNA and the ribosomes what do they really do it's not too hard to understand it's that here's our mitochondrial DNA with this I could do two things with it one is I can make more of it what's that called DNA replication this could be important if I want to take maybe and replicate my actual mitochondria so if I want to take this mitochondria and maybe undergo what's called a fission process and make two of these puppies here let's say that I

wanted to make two of these mitochondria I would want them both to contain an equal amount of mitochondrial DNA you know what's super interesting believe it or not so fission is a process where bacteria prokaryotic cells undergo division there's a theory um back in the day called well it's still there it's called the endosymbiotic theory the mitochondria back in the day used to just be a bacterial cell a prokaryote and it would have its own DNA and then what happened is it got engulfed by a eukaryotic cell and then when it got engulfed inside of

the eukaryotic cell it then became something called a mitochondria and so it kind of started down regulating a lot of its genes and proteins and stuff like that and the nucleus of a eukaryotic cell became the new Factory of DNA and it has it cytoplasm to make many of the proteins that are needed and the mitochondria just primarily kind of got downgraded to producing ATP and having some metabolic reactions occur in it so that's something called the endosymbiotic theory but that's a really cool concept that basically the mitochondria used to be something called prokaryotic cells

and they just got engulfed by eukaryotic cells and they got downgraded to becoming a mitochondria which is kind of interesting but that's one thing is we can kind of replicate them to make more of these types of mitochondria via process called fission the other concept here is that we can take this mitochondrial DNA and undergo transcription and we undergo transcription this makes something called RNA and these RNA molecules combined with the ribosomes located in the mitochondria and here's another important Point these ribosomes are called 70s ribosomes you know what they are in the the cytoplasm

of eukaryotic cells which we'll talk about soon they're ads that's another question they could potentially ask you so watch out for that but from this mitochondrial DNA can replicate to undergo division of the mitochondria or it can make RNA and that's really important because you need the DNA to make RNA you need the RNA to be translated and the translation process will then synthesize particular types of proteins and these proteins that it makes generally accounts for about 15 percent of the proteins that are needed for the mitochondria to be able to perform its functions so

that means it needs a decent chunk about 85 of the proteins to come from the nuclear DNA nuclear RNA than to get translated by the cytosolic ribosomes and they get transported across the mitochondrial membrane so that it has those functions that's a really cool concept and my friends that finishes off our discussion on the mitochondria their structure their function I hope it made sense I hope that you guys take again the step-by-step process we go through the inner outer membrane we went through the inter membrane space talked about their involves in protein transport the electron

transport chain and the miscellaneous transport and then we dug into the Matrix a little bit and then we talked a little bit about how the mitochondrial DNA are involved in replicating itself for the actual mitochondria to divide or making proteins via transcription translating those by ribosomes in them 70s ribosomes to make proteins for it to function we also talked about all the metabolic reactions that are plentiful and occurring inside of the mitochondria Matrix I hope it made sense and as always the engineers until next time [Music] thank you