all right engineers in this video we're going to talk about the electron transport chain so if you guys kind of remember going back to just kind of reviewing everything of how we got up to this point of the electron transport chain you remember that we started with our six carbon sugar which is called glucose and then it underwent some oxidative steps and through that oxidative steps it actually produced two adhs and a net of 2 ATP and it ended up producing two of these three carbon molecules which is referred to as pyruvate and then what happened if you guys remember if nadh if there's oxygen present nadh can come and drop his electrons onto the electron transport chain and then pyu can move in to become acet COA but if there's no Oxygen nadh drops those electrons onto pyruvate and converts them into lactic acid but in this case let's say that the nadh comes and drops off his electrons and we'll show that later and then if that happens pyruvate is now free to go in to the actual mitochondria and then what happens you remember pyruvate comes into the mitochondria and here's our three carbon pyruvate so there's our three carbon pyruvate and then you remember pyruvate under goes some specific steps here uh through the pdh enzyme which actually pulls out a CO2 for if there's two of these pyruvates though you get two co2's and it pushes out a nadh but specifically two of them for each acetyl COA then if you remember what happens this acetyl COA does what so then it goes citrate combines with oxyacetate to form citrate citrate goes to isocitrate isocitrate goes to Alpha ketoglutarate Alpha deuterate goes to suin COA suxin COA goes to soate soate goes to fumate and then fumate goes to malate and throughout this whole cyclic amphibolic pathway we produced a total of six nadhs two fadh2s two atps and two co2's now where are these nadhs and these fadh2s going to go and take those electrons if you look here we have the mitochondria right so this kreb cycle reaction that's occurring here in the mitochondrial Matrix now on the inner you see this folded it's called the chiste this folded inner mitochondrial membrane that's where our actual electron transport chain is present so if we look at each one of these guys individually so let's say here is our first electron complex so look at this guy here's our first electron complex this guy right here is actually going to be called complex one okay so this guy is called complex one now what happens at complex one is you see nadh there's a specific enzyme in this area that's going to take those electrons from the nadh so watch this nadh comes through this actual enzyme complex one and then enzyme complex one pulls the electrons off of nadh so it turns him from 6 nadh to 6 n a positive and then what happens is it rips the electrons off and displaces the proton so now let's draw that proton look the proton is actually going to be over here now so that proton got displaced so there would actually be like a proton over here but that proton I'm just drawing it over here as a result okay so he drops those electrons so now he has the electron so let's draw the electron here on his head so here's the electron right there there's our electrons the two electrons that he's dropping off now at the same time this fadh2 he has a high affinity for this enzyme complex this enzyme complex is specifically called look at this guy this guy right here is called complex 2 okay so this is going to be enzyme complex 2 and look what fadh2 does fadh2 comes over to this complex 2 and reacts with complex 2 and what complex 2 does is it pulls the electrons off of the fadh2 so then it pulls the electrons off so he gains those two electrons so let's show those two electrons then that he pulls off of them let's put them right over here here's the two electrons that he Yanks off of the actual fadh2 and then the fadh2 gets converted into two fad and it'll also have a proton over here that it has hanging out right now the next thing that happens these two guys nadh drops his electrons onto complex one fad2 fadh2 drops his electrons onto complex 2 what happens is something really cool this guy is going to act a little bit differently than this guy when this guy gains the electrons imagine here I have a graph let's say here I have a graph just to represent a concept here over here on the Y AIS is Delta e which is energy and then as we go along here this is going to be the the reaction of the electron transport chain reaction right the progress Watch What Happens let's say that this black is enzyme complex one let's say this is his energy value but then you give him electrons electrons are high in energy and it takes him up to high energy levels usually molecules don't like to exist in high energy so what they do is they want to get rid of that so he's going to get rid of those electrons when that happens he goes down to low energy levels so what does he do then with these electrons he takes and passes these electrons onto this guy here when he does that he goes down to low energy levels that energy transfer creates this uh change in this molecule and you see this pore right here it opens the pore up when that pore opens protons get pushed out because generally watch this now the protons are going to get moved out into this space over here so now the protons are going to be out here they get pumped out into that space okay so now the proton got pushed out who did that the enzyme complex one now enzyme complex 2 is a little different so look what happens he gains these electron so let's represent this guy in green now let's say he has these electrons right here he's at that level he gains those electrons and goes to high energy levels and then he what does he do he takes these electrons and does what passes these electrons on to this guy when he passes those electrons onto this guy what happens is he's going to drop down to low energy levels he's going to return to low energy but when he does that does he have a Poe no so this prot that's hanging out here it can't get pumped out okay so that's interesting we'll come back and explain how that's significant at the end of this okay who's this guy that's accepting these protons from complex one and complex 2 this guy right here is a sneaky sneaky guy okay this guy right here is sneaky sneaky all right what is this guy this guy is called coenzyme Q okay so this guy's called specifically co-enzyme Q or they even call it yinon now what happens this guy accepts those electrons this molecule is not protein based but what he can do is he can move across the actual cell membrane so he can move he's a mobile molecule and what he does is is he takes these electrons that he got from these guys so let's represent this for right now as just R so that we keep it simple here so this is going to be the electrons he's going to take those electrons and he's going to pass it over to this guy so now let's represent that coenzyme Q is going to take those electrons and he's going to pass those electrons onto this guy so what's he going to pass over here he's going to pass over the electrons onto this guy right here so you're passing over these electrons when you pass it over to this guy right here this guy right here is actually called complex 3 okay enzyme complex 3 now enzyme complex 3 is pretty cool also enzyme complex 3 is going to take these electrons and same thing let's rep come over back to this graph and explain what happens with that enzyme complex 3 which are going to represent in blue he's going to accept he's down at this level but then what happens is he accepts those electrons and goes to high energy levels when he gets the electron he doesn't want to hold on to the electron so what does he do he passes it onto the next guy so it's just like these guys are playing Hot Potato Hot Potato Hot Potato right they just keep passing the electrons down the line when he accepts these electrons he doesn't want to hold on to it so he's like I'm going to pass this electron on to the next guy so he takes this electron and passes it onto this guy right here and then he accepts that electron okay what is this guy called this guy right here is a cool mobile molecule this guy here is very very special because he's actually going to be made up of what's called uh specifically it's a cytochrome and cytochromes are basically they have a heem structure with a central iron usually in the center this is called cytochrome C okay so this is specifically called called cytochrome C now cytochrome C if you look at this guy right here okay this cytochrome C right here is actually going to accept these electrons and then take these electrons and then what would happen to him let's come back over here to the graph if we come over to this graph he's going to be at low energy levels when he's at low energy levels he's going to accept the electrons and go to high energy levels doesn't want it what is he going to do he's going to pass the electrons onto the next guy and if you already get the point here what would happen with this last guy that we're going to explain let's say here's your last one and we'll talk about him in a second if he accepts those electrons what's going to happen to him he's going to go to high energy levels not going to like it pass the electrons off so let's come back over here so now he gets these electrons doesn't want to hold on to the electrons anymore so what does he do he takes these electrons and passes these electrons onto the next guy it's just Hot Potato Hot Potato Hot Potato right this guy when he accepts these electrons like I told you before he goes to high energy levels and he doesn't like that but let's come back over here for a second look at this guy look at cytochrome c cytochrome c when he accepts the electrons right he goes to high energy levels then when he goes to high energy levels what happens he doesn't like it he passes the electrons on let's come back over here what happens here at complex 3 same thing he accepts the electrons it's too high energy doesn't want it passes the electrons over what did I tell you happens if this guy has a pore here when he's at high energy levels he doesn't like that electron passes it on to the next guy and then the energy level drops that there's energy released that energy released opens up this pore and then who starts flowing out this is going to be protons where would these protons be coming from they could be coming from this guy they could be coming from the nadh and these protons are going to be accumulating in this area here and then look what happens we're going to take this proton and we're going to pump this proton out into the intermembrane space Oh this is this area right here that we're in this is the I know I told you it was the mitochondrial Matrix but let's just you know reiterate that that this area here is the mitochondrial Matrix this space right here is called the intermembrane space okay so that's where the protons are being pumped from from the mitochondrial Matrix into the intermembrane space now coming back over here he accepts these electrons if he accepts these electrons he goes from high energy he passes the electrons onto the light next guy goes back down to low energy but does he have a Poe no so can he pump a proton out no so no proton comes out through this guy but then the electron gets passed onto this next guy what's this next guy here called this guy right here is actually called complex four but sometimes you might even he hear it referred to a cytochrome oxidase okay and what happens here with this complex 4 so let's say here's our complex 4 look at this guy he's ready to do some good stuff he's about to help our body out look what happens so this electron gets accepted onto this guy but again he goes to high energy level doesn't want those electrons he passes those electrons off onto someone else there just so happens to be this cool little dude circulating in this area his name is oxygen so 1 half of an oxygen are just an atomic oxygen and also two protons that are going to be out in this vicinity here because again there's going to be protons all over the place it's going to come over here and then look where this electron's going to go this electron is going to get passed onto the oxygen and that oxygen is going to combine with this electron so now look what happens this oxygen and this proton are going to combine with this electrons particularly two electrons and as a result what are you going to produce you're going to produce water okay so let's go ahead and just recap that quick all the way down okay nadh from the crab cycle is going to be or even from the transition step is going to be dropping those electrons onto two complex one he goes from high energy doesn't like it passes the electrons onto coenzyme Q when he does that and he goes from passing that on he goes back down to low energy pumps a proton out from the mitochondrial Matrix into the inner membrane space at the same time over here fadh2 from the kreb cycle is going to be coming in dropping those electrons off onto complex 2 when he drops those electrons off onto complex 2 he goes from high energy passes those electrons onto co-enzyme q and he'll go back down to low energy but there's no pore to pump a proton out co-enzyme Q is one of the ultimate electron acceptors he accepts those electrons and then runs the actual electrons on the membrane over to complex 3 complex 3 or even they call cytochrome B is going to accept these electrons when it accepts these electrons it's going to go to high energy levels but then it doesn't want to hold on to those electrons so it passes on to cytochrome C when he passes those electrons on he goes down to low levels and pumps a proton out from the mitochondrial Matrix into the inner membrane space the electrons get passed on to cytochrome C he goes from he goes to high energy doesn't want it passes it onto enzyme complex for or cytochrome oxidase and then whenever you pass it to cytochrome oxidase this guy goes to low energy levels but he doesn't have a proton pump so he can't pump anything out into the inner membrane space but then when enzyme complex 4 cytochrom oxidase gains those electrons he goes to high energy and then when he goes to high energy he doesn't want to hold onto those electrons so he passes it on to oxygen which is your final electron acceptor and then when he does that he goes down and to low energy levels so what do you think he's going to be pumping out into the intermembrane space from the mitochondrial Matrix he's going to be pumping out a proton okay so he's going to be pumping out a proton you could expect now protons are positively charge so you should expect a lot of proton accumulation out here so a lot of positive charges are being built up in this intermembrane space and I'm drawing a lot of these that you get the point that the proton concentration out here in the intermembrane space is much higher than the proton concentration down here in the mitochondrial Matrix so again what will be the proton concentration o over here it would be very very high we use brackets to express it in concentration right and then over here look right over here on the mitochondrial Matrix what's the proton concentration it is low now generally biology loves to say that things like to move from high concentration to low concentration okay that's that's their passive or their their diffusion gradient their concentration gradient their electrochemical gradient now how does this protons move through okay so here's this big really really significant molecule and this molecule right here is called this one here is called ATP synthes and sometimes they even call a complex five okay because if we go all the way down it gets the enzyme complex 5 now ATP synthes is really cool because what he does is if we look here at the structure of it so let's say I actually kind of just really quick annotate these structures here so this part here from this part here to this part there this is actually specifically referred to as the actual rotor and also this part right here is the rod so this part here is the rotor this is the rod this is the catalytic knob and then this over here you see this structure here with this whole long structure here this whole thing right here is called the stat okay so again let's let's denote that one more time this part here is called the catalytic knob this part here is the rod which is anchoring the rotor to the knob then the rotor is going to be connected to this stat and the stat is what's holding this knob to the actual membrane so it's anchoring this actual catalytic knob to the mitochondrial membrane now these protons are accumulating out in this area the protons will then do something really cool you see this stat it has a little hole in it a little hole right there these protons are going to start moving through that hole and then they're going to exit out through the bottom of this hole so they're going to move through this hole right here and then they're going to exit out through the bottom of this hole when these protons start moving from areas of high concentration to low concentration so what's going to come out of this you're going to get a proton out of this when the protons move from high concentration to low concentration this rotor start starts spinning and then the rod starts spinning so what do I mean by that once this proton comes through this rotor starts rotating the rod starts rotating and the rotor starts rotating as this starts rotating from the protons moving from high concentration to low concentration this ATP synthes structure starts absorbing what's called potential energy so again one more time as the protons start moving from high concentration to low concentration this rotor starts rotating the rod also starts rotating and then as that starts happening as that rotation occurs from the movement of the protons from high concentration to low concentration or from inner membrane space to mitochondrial Matrix this ATP synthes absorbs potential energy out of that reaction and uses that potential energy for a special special function you know over here on this knob there's a lot of catalytic sites it actually goes Alpha Beta Alpha Beta Alpha Beta subunits but a specific subunit which is the beta subunit it's going to take that so let's say here I have the beta subunit and here's my ADP and here's my inorganic phosphate and it's all bound to that beta subunit as this thing starts rotating okay as this thing starts rotating the beta subunits actually holding on to so imagine my on my finger right here this one right there I'm holding ADP and on my thumb right here I'm holding the phosphate as the actual rotor and the rod starts rotating and sucking that potential energy the catalytic knob absorbs that energy and uses that energy to watch this ADP phosphate I'm going to smush them together when I smush them together what do I get I get an ADP and a phosphate fused together so what does that produce out of that I'm going to make a TP adenosine triphosphate that's our that's our form of cellular energy so again what happens as this rotor rotating as the rods rotating the catalytic knob specifically the beta subunit is holding on to the ADP and the inorganic phosphate they suck the potential energy from this rotation and the movement of the protons and then they take the ATP and the phosphate and smush them together and make ATP so when the protons are moving from high concentration to low concentration this thing is sucking the potential energy out of that reaction and then it starts to make ATP this is referred to as the chemiosmotic theory okay the chemy osmotic Theory and all the chem osmotic Theory says that as the protons move from high concentration to low concentration the ATP synthes absorbs some of that potential energy from that movement and then they use that energy to convert ADP and inorganic phosphate to make ATP and this is through a specific type of phosphorilation that we refer to as oxidative phosphorilation because as you know we've talked about other different types of phosphorilation which is referred to as specifically substrate phosphorilation and that was done within the kreb cycle and that was also uh performed within glycolysis okay so that got us a lot of ATP now let's finish up with explaining one last thing this nadh how many protons is it truly pumping out because that's going to help us to calculate all the ATP that's being produced this nadh let's just say that we take one n DH this nadh is dropping this electrons off into complex one as a result he's pumping a proton out of complex one but those electrons that he passes on as a chain effect who else do they go to they go to Q does any proton get pumped out here no then they go to three does a proton get pumped out here yes so that's two two that's two protons then those electrons get passed on to cytochrome C does a proton get pumped out of this no those electrons though the same electrons get pumped over to I mean moved over to complex four are cytochrom oxidase does a proton get pumped out here yes so how many protons did one nadh actually drop off just one one nadh will give you three protons and let me just clarify this I know I told you that I was is dropping off six nadh is here but really only two electrons are coming from one nadh okay just realize that we produced six nadhs from the kreb cycle same thing here two fadh2s they're only passing off two electrons okay so one fadh2 is passing off two electrons but just realize that you're making two fadh2s from the kreb cycle okay so we produced three protons with one nadh all right now what about fadh2 he's dropping those electrons off onto complex 2 then where are those electrons going well is any proton being pumped out of complex 2 no they get passed on the Q we already know that no proton gets pumped there okay where else do they get pumped out as a result the electrons get passed on to three and then a proton gets pumped out that's one then they go to C no proton gets pumped out here then that same electrons get pushed over to cytochrome 4 or I'm sorry cytochrome oxidase or complex 4 then what happens a proton gets pumped out there how many protons does that result in two so one fadh2 gives you two protons and then what did I tell you for every one proton moving down its concentration gradient we produced One ATP so if you think about it we can even rewrite this whole concept here how many uh nadh's I if you have one nadh it's actually producing not just three H+ but really 3 ATP and this guy's not only pushing two protons out into the inner membrane space but those protons are being used to make ATP so he's actually producing two ATP okay so now that we've actually done all of this electron transport chain we went through glycolysis we went through the transition step we've gone through all of these different types of activity specifically pertaining to carbohydrate metabolism let's go ahead and calculate or tally up all the actual nadhs and fadh2s and atps that we make and see how much is actually being made throughout this entire process that we've gone through in the series of videos so let's start off with how many nadhs did we produce total so start off with nadhs okay so from the kreb cycle I produced six nadhs so let's tally all of this up so let's get this CO2 out of the way so now if we have a tally the first one was kreb cycle and then we produce from this six nadh es okay also from the KBS what else did we produce we also produced two fadh2s then what oh we produced two ATP from the Krebs also right so we produced two ATP from the Krebs by what's called substrate phosphorilation remember this is substrate phosphorilation then what else oh look we got the two nadh's for the transition step so then what do we have we have two nadh's from the transition step so from the transition step just going to denote that transition we get two nadh's so those will be used in the electron transport chain then what else okay if we come over here oh we got two nadhs from specifically glycolysis right so two nadh is from glycolysis so let's say over here we come to glycolysis we produce glycolysis will give us two na dh's okay what else now technically we can add in this to ATP but let's do that afterwards at the end and I'm going explain why okay let's tally all of this up if this comes together now you'll remember that one nadh gives me 3 ATP one fadh2 gives me 2 ATP okay if that's the case then how many how many nadh's do I have here then I I'm going to start this one by one if you look here six nadh's there's three ATP for one so if you do 6 * 3 that gives you 18 ATP for just that part then if we do the next part two fadh2s for every one fadh2 I get two ATP well there's 2 * 2 so this is going to be 4 ATP then I get 2 ATP just directly from the kreb cycle by substrate level phosphorilation then also look two nadhs one n ADH is 3 ATP so 3 * 2 is going to be 6 ATP and then I got another two n adhes so that'll be again another 6 ATP if we sum all of this up we're gonna get 36 ATP so you're gonna get approximately 36 ATP now I'm going to denote this this 36 ATP is under only aerobic conditions so this ATP that we've actually made is only going to be under aerobic conditions in other words oxygen has to be present if you come over here these two ATP that we actually netted from glycolysis that is not aerobic that's an anerobic oxygen that we that's o we produced ATP by Anor robic mechanisms in that reaction so in other words if we add in an additional I'll draw it in a different color so that we know that it's a different type of 2 ATP this is from anerobic processes specifically from glycolysis so what does that sum up to in total this gives us a total of 38 ATP in whole okay so out of this we technically can produce a total of 38 ATP if we consider the 36 ATP from aerobic cellular respiration and then the 2 ATP that we can get from glycolysis via anerobic respiration all right Niners we've covered everything that we possibly can here for the kreb I'm sorry for the electron transport chain I hope it all made sense I hope you guys really enjoyed it if you did hit that like button put a comment down in the comment section we look forward to hearing from you guys and please subscribe all right Engineers until next time