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0:07
all right Ninja nerds in this video we're going to talk about glycolysis so in short just a little definition of about glycolysis is they're going to oxidize a molecule called glucose so you know glucose is a sixc carbon molecule it's basically a monosaccharide which is just a fancy word for sugar so glucose is a six carbon molecule and we're getting that from our diet we'll talk about how exactly we're getting it from our diet in the Digest system but for right now we're just going to say that
0:33
we're bringing glucose into our cells which is again is a six carbon molecule and we're going to oxidize him through various steps about 10 steps to eventually convert that into pyruvate at least two pyruvates which is two three carbon molecules but the question is how can we get this glucose this six carbon molecule into this cell how do we do that because you know glucose so again what is this molecule right here guys this molecule right here is specific Al called glucose let's
1:01
actually write it in red make it nice and Purry so again this is called glucose so glucose is our six carbon molecule we're denoting that by these circles that's 1 2 3 4 5 six thing is though glucose is actually going to be a water soluble solute in other words it can't actually move through the cell membrane by diffusion by passively it has to come through some type of Transporter A specialized transporter these specialized Transporters are called glut Transporters so again what
1:34
is this one called here it's specifically called a glut transporter but let's say that we're having this occur in different organs you know glut Transporters so you know glut is glucose transporter they're the ones that are bringing this glucose into the cell but they're not just one direction they're bidirectional so at the same time they can bring glucose from actually what inside of the cell to outside of the cell but there's many different types of glut receptors one
2:00
way that I like to just easily quickly remember all of them it's a helpful pneumonic in my opinion it's up to you guys whether you guys like it here but it goes like this see write like this B B B okay kids lips are but this doesn't matter okay pink mother father okay so it's just a little quick way that it helps me to basically categorize my glut receptors and it's going to go in a specific order so this is actually going to be for glut one this is going to be for glut two the
2:41
pink is going to be for glut three and mother and father is going to be for glut four now what does each one of these things mean so BBB the first B I like to remember is blood but specifically what type of blood I mean the red blood cells so on the red blood cells plasma membrane they have a glut one receptor I also like to remember B for baby but we don't say baby we say the fetus so the fetus is actually going to have glut one receptors okay and then the last one is the bloodb
3:15
brain barrier so blood brain barrier you know that's the the actual separation between an actual vessels and the pamat and the neural tissue with the astrocytes around them we'll talk about that more in the neurophys ology but again these are the three easy ones to remember for glut one BBB blood specifically red blood cells baby but I like that we should be Technical and say fetus and the third one is BBB blood brain barrier all right what about the second one so I like to
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highlight here Ki I like to highlight the LI I and I like to highlight the p and the S right so what does that give me well the Ki is going to give me kidney so the kidney has as glut two receptors the LI is for the liver and the PS is for the pancreas there is other tissues these aren't all of them obviously you can also find the within the the gastrointestinal tract there is certain types of glut two receptors also but anyway glut three pink so I like to remember the P right there the P for
4:24
placenta the N for neuron and another k for kidney so it's not not that bad right when you think about it so again what is it going to be it's going to be placenta and then we're going to have neurons are going to have these glut three receptors don't get that confused with the actual glut one which is for the blood brain barrier okay that's different okay because this is going to be where the astrocytes are right between the blood vessels and the astrocytes so don't they get that
4:50
confused with the actual neuron cell membrane okay then k is going to be for again the kidney and then the last one mother father I like to remember M for muscle and F for atopos are fat so again what would this last one be here mother and father is going to be specifically we'll just do these individually mother is for muscle and father is for fat but we should be Technical and say atap POS okay so the whole purpose of this is just helping you guys to realize that there's many different glut
5:23
Transporters and what they're doing is they're bringing glucose from outside of the cell to the inside of the cell but they are bidirectional so they can move it out one more thing I want to mention and I want to highlight this one glut 4 he's very very particular and the reason why I mentioned all these was particularly for this one and why I want to say this is because glut 4 is different from a lot of these other ones these ones are generally insulin independent in other words they don't
5:48
depend upon the concentration of insulin for their amount this one though glut 4 is insulin dependent what does that mean that means when insulin is present he can help to be able to increase the number of glut four Transporters or increase the efficiency of the glut four Transporters whereas glut one glut two glut three they don't really depend upon the presence of insulin they can function and bring in glucose into the cell out of the cell and they can regulate it based upon the presence of
6:16
glucose not by the presence of insulin but again that's a quick thing to remember okay so now that we have all of our glut Transporters and we know exactly how this glucose is actually getting into the cell now we can move on okay so we bring glucose into the cell through one of these glut Transporters depending upon the organ once we bring it in we have to chain it you know what I mean so because remember what I told you this is actually biral so at the same time glucose could move out to
6:44
prevent this actual glucose from moving back out we have to put something on it to prevent it from leaving so what we do is we put a special molecule on it look at this so let's say that this is carbon number 1 2 3 4 5 six okay and on the six carbon I have a special thing coming off of it look at that that right there is a phosphate so what did I just put here I put on here a P4 3 negative group all right that's our phosphate group we put a phosphate on the six carbon of glucose so what this
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what what is it going to be called well this was glucose there's a phosphate on the six carbon of glucose this must be glucose six and I'm just going to put P but you guys get the point it's for phosphate okay if I abbreviate some of these I'll I'll try to explain them it's just easier to write them down in abbreviation sometimes okay now we got this glucose 6 phosphate the question is how the heck did that happen how did I get this with no phosphate to a phosphate there had to be some enzyme
7:45
involved yes there was what is the name of that enzyme that's involved this enzyme it depends upon the tissue and we'll talk about it there's two enzymes one is going to be called hexo kinas okay okay one is specifically called hexokinase the other one is going to be called glucokinase now we'll keep it the same color the other one is going to be glucokinase and what is the difference okay hexokinase is actually going to be present within the muscles or other
8:22
different tissue cells so many different tissue cells but a lot of it is concentrated in the muscles te technically they call this hexokinase type 2 two glucokinase is primarily in the liver so let's actually put that here so hexokinase can be a many different tissues like the muscle it can be in a lot of different tissues any different tissue in the body but the liver is the only one that has glucokinase but they also call it hexokinase 4 just let you guys know okay
8:50
so that was the first step and this is what it's doing it's involved in this step right here these two enzymes depending upon the tissue are involved in the conversion of what glucose into glucose 6 phosphate now the question is where did that phosphate come from I'm glad you guys asked it's coming from taking ATP and converting it into a DP so what happened then I had three phosphates right because that's adenosine triphosphate then I went to adenosine diphosphate that means I lost the
9:20
phosphate where' it go onto the six carbon of glucose who is facilitating that hexokinase and glucokinase Next Step we're going to go from this molecule now right we're going to go from glucose 6 phosphate to this this this guy right here but now look at this I'm still going to have the phosphate here okay that phosphate is still present the only thing that's different is all I did is I switched a couple different molecules around a little bit so I switched glucose and I
9:47
switched its carbonal form into different types so all I did was I underwent isomerization so in other words glucose 6 phosphate and this other one right here which is called fructose 6 phosphate had the same number of carbons same number of hydrogen same number of oxygen primarily glucose is usually an alahh and fructose is usually the form of like a ketone okay so these guys are just interconverting between like an aldah and a ketone so they're just isomerizing so this step right here
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step number two because this is Step number one step number two is going to be catalyzed by a phospho hexos iSeries
10:29
okay so phospho hexo hexos isomerase because you know hexos just means six carbons so it's a six carbon sugar right here all of this enzyme is doing is converting glucos 6 phosphate into this other guy what is this guy here called this guy here is called fructose 6 phosphate so again what is he called fructose six and I'm just going to put the P guys for phosphate okay so that was the second step now we're going to go into the third step we'll talk about this third
11:00
step in great detail in the other video when we talk about regulation but in this third step it's a very important step just like this first step is a very very important step and you can tell the difference why can you tell the difference this is a Black Arrow this is a pink Arrow the pink arrows are reversible steps so what does that mean that means not only can I go from glucose 6 phosphate to fructose 6 phosphate but I could go from fructose 6 phosphate to glucose 6 phosphate but if
11:26
I wanted to go from fructose 6 phosphate to this next molecule that possible but I cannot go through that same pathway backwards this step is not reversible by this enzyme that we're going to mention they have to move through another enzyme so this is a irreversible step very regulated okay so the enzyme involved in this step is going to be that of phospho fructo kinas one and like I said I'm just going to uh abbreviate that pfk ones which stands for again phospho
11:58
fructo cese type one it's involved in this step here okay exactly how is it involved what it's doing is if you notice I'm going to I'm going to show you something here this was the six carbon this was the one carbon right and then you guys can do the math 2 3 four five on the six carbon we still have that phosphate nothing has changed there and now it's going to be on the one carbon so now we have a phosphate on the sixth carbon and we have a phosphate on the number one carbon what must this
12:28
molecule be called he has a phosphate on the sixth he has a phosphate on the 1 he should be called fructose 1 comma 6 Biz phosphate why do I call bis phosphate because you probably heard the term B phosphate and bisphosphate bisphosphate means that there's carbon spaces between it bif phosphate means that they're right next to one another okay so Biz phospho means that the actual phoso phosphate groups are actually separated they're couple carbons away where by phospho means that
12:58
the next to one another okay but in this case it's Biz okay so what is this molecular called fructose six I'm going to put bp4 bis phosphate okay what is the enzyme involved in that step the pfk1 right what happened I had one phosphate originally on the six carbon then I added another one oh I must have done the same thing that I did in this step here yep so ATP gets involved in this step here and he loses a phosphate and gets converted into ADP so I took ATP and converted into
13:37
ADP Okay cool so I lost an I actually used up an ATP in that step now look what happens here I take this fructose six bis phosphate which is six carbons 1 2 3 4 5 six and I split it in half to two three carbon fragments okay but the phosphate on this carbon right here should be on this carbon here so now let's put a phosphate over here okay and then that phosphate that's going to be over here it should be right there all right cool and again what is this guy right here this is a phosphate
14:14
and again what is this guy right here called This is a phosphate okay now that we've done that what are these guys called now these ones are a little bit harder to name okay unfortunately I'm going to give you guys a pneumonic at the end'll help you a little bit with that but this guy right here is called di hydroxy acetone phosphate okay so it's a three carbon molecule with a ketone in the middle and a phosphate on that carbon right there okay we could technically call it the
14:46
one carbon but it wouldn't matter because on either side you know no matter how you name it nen clature wise it doesn't matter so dihydroxy acetone phosphate okay there's that guy now the thing is dihydroxy acetone phosphate isn't really utilized in this actual glycolysis pathway he has to be converted into another molecule what's this molecule here called this one right here is different from this guy this one is actually having an alahh on one end so we call him glycer
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alahh glycer alahh three phosphate okay sometimes you might even see it like I'm actually going to denote this one as DHA hydroxy acetone phosphate and this one you're probably going to see in other videos as g3p glycer alide 3 phosphate okay now here's the thing what enzyme was involved in splitting this puppy okay they call this enzyme involved in this step here right or we can even say if you want to involved in this step here it's the same enzyme it's just cleaving it this enzyme is called
15:57
alalas here let's actually do it like this instead let's just kind of encase it around this so we'll Circle this and this he is involved in both of those steps so he's actually doing what he's cleaving fructose six bis phosphate into what dhap and g3p now like I told you dihydroxy acetone phosphate doesn't really get it doesn't actually convert into this next glycolytic intermediate he has to be converted into glyceride 3 phosphate in order for him to be converted into this next intermediate so
16:26
we have to have an enzyme that is allowing for this interc conversion between the two or isomerization that enzyme that is involved in this step is called a triose because it's a three carbon molecule phosphate I'm going to put P isomerase so it's called a triose phosphate isomerase enzyme and it's involved in the interconversion between g3p and dhap or dhap to g3p okay primarily with a little bit more of it going towards the g3p depending upon the body's diens hands though all right
17:00
we'll talk about that in other videos now glyceride 3 phosphate what happens to him he is then going to get converted to this next guy here okay well this guy here has a phosphate on what carbon so let's number this carbon here one 2 three okay well that means that the the phosphate is on the third carbon that's why we named it that well then it should still have a phosphate here I would suppose right let's see okay it has a phosphate here but oh would you look at
17:27
that there's another phosphate huh so I added another phosphate okay that's cool now what had to happen then and what what would we call this molecule here we would actually call this molecule specifically 1 comma 3 now because the phosphates are actually having a space between them this is Biz Biz phospho and then it's actually because it's a three carbon glycerate okay so it's called 13 bisphosphoglycerate that's this molecule here now there's a special enzyme
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involved in this step it's a pretty cool enzyme this enzyme is working right here in this step and I'm going to kind of abbreviate him also he is called glycer alide three phosphate just like that but dehydrogenase okay this is an important step okay a very important step here what's going to happen is this enzyme this glyceride 3 phosphate dehydrogenates he's going to do two things he's going to add two things into this reaction one thing I'm going to do is I'm going to take NAD positives in
18:37
this step okay so I'm going to show it coming off of the I'll show it coming off of this reaction here so look I'm going to have NAD positive he's going to react with that glycero 3 phosphate in the presence of this enzyme and what he's going to do is he's going to rip off hydrides off of the g3p and when he does he gets converted into NAD DH what is hydrides hydride is just a fancy way of saying here's my hydrogen and then this hydrogen it's going to have a proton you
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know within the center of it and then all what's going to be around it generally has just one electron but in this case a hydride has two electrons so what do we say a hydride is technically we say a hydride is really a proton plus two electrons okay that's what's going to be our hydride and that's what this NAD molecule this NAD plus is doing it's picking up hydrides and getting converted into nadh here's the here's the tricky thing though look at this I want you guys to really really see
19:38
this this is fructose 16 B phos he gets converted into dhap and g3p I told you most of this guy is getting shifted over here so how many of him do I really actually have I have two okay I have two of him because I told you most of this is getting shunted over here and then he's running through this reaction twice so if that's happening twice then how many nads am I actually producing I'm actually producing two I'm having two nadh is being made okay cool that
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doesn't account for this phosphate this enzyme's so tricky he loves to just add in an inorganic phosphate so you see here I'm going to have an inorganic phosphate I'm just going to throw that into the reaction so g3p dehydrogenase is going to just throw a phosphate into the reaction and generate in ind's Okay cool so we're good with that step now we're going to move on to the next step now look what happens here you're going to notice something different oh did I draw a phosphate over
20:38
here no I did not what does that mean that means that there's I lost a phosphate somewhere but again what would we call this one okay well there's it's going to have a similar name but just get rid of the one it's a three but no Biz it's just a three phosphoglycerate that's it so what are we going to call this one three phospho gly glycerate okay that's the name of this substrate so again what is this one here called three phosphoglycerate now in this step there's a special enzyme involved
21:11
here this enzyme is really cool and what he's doing is he's actually going to help to form let's do this in a nice pink color here I'm going to take a DP and convert it in this step to ATP okay but because this reaction is happening twice how many am I actually producing guys two okay so I'm actually producing two ATP in this step right here okay this enzyme is pretty cool this enzyme right here that's working in this step is called phospho glycerate kinas okay so phosphoglycerate kinas is
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really really special because what he's doing is what what is the definition of a kise we've talked about it when we talked about hexokinase and glucokinase but kinas is by definition something that phosphorites a substrate okay what is it phosphor lating it's phosphor ADP where is it getting that phosphate from the 13 BPG it's ripping it off of the one carbon and giving it to ADP to make ATP so that's what he is involved in he is involved in this step here okay good we got our 2 ATP all right
22:26
that's cool okay so now this three phosphoglycerate great nothing crazy is going to happen in this next reaction it's nothing us not a really special you know reaction nothing significant but look what happened to the phosphate all I did was I switched it I mutated it and I switched it from the third carbon to the second carbon because again we denote this one two 3 same thing here one two 3 so I switch it to the second carbon so what would you guys suppose
22:53
this is going to be this guy's name two phosphoglycerate not the crazy on this one two phospho glycerate okay cool now the the enzyme involved in this one is not really uh that important but we'll mention it anyway just that you guys can have that the enzyme involved in this step converting the three phosphoglycerate into the two phosphoglycerate is just called phosphoglycerate mutase so phospho glycerate
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mutase okay that's that enzyme and he's stimulating this step okay cool now the two phosphoglycerate is going to go to kind of an interesting step okay so what he's going to do is this phosphate is on the carbon here right so like let's say that here I have a three carbon structure just for a second I have a three carbon structure and then what I have here is I have the phosphate coming off what I'm going to do is I'm going to switch some structures around and I'm going to
23:56
convert this into what's called an enol and an enol is just when you have according to organic chemistry it's a double bond between these carbons with an alcohol coming off like that that's an enol but what I'm going to do is is I'm going to put the phosphate on that now okay so I'm going to have it kind of like switched off a little bit so because I have this different kind of structure what I'm now going to have is is I'm going to have this phospho enol and it's a three carbon structure like
24:26
this last one pyruvate so what is this last molecule here called we call this molecule phospho enol pyruvate so this one here is called phospho enol pyruvate but I don't like that I like pep okay it's easier to remember okay but it's you know it's up to you all right so pep and what am I doing all I'm do is I'm shifting it into a different kind of structure so it's just making it a little bit more modified now okay and then again this is going to be my phosphate so what do I call this
25:01
phospho enol pyruvate the enzyme that's doing that is trying to convert it into an enol so it's called an enalas so what is the enzyme involved in this reaction here the enzyme involved in this reaction is called a enalas okay nothing crazy really the more important steps in this process is the black lines one that I mention as well as this reaction here okay last one I'm taking the phosphoenol pyruvate and look what happens no phosphates that means that I must
25:30
have formed ATP again yeah so what did I do that means I took two adps again reacted them with this phosphoenol pyruvate it made to atps what does that mean guys you should automatically your brain should start clicking kinas it's got to be a kinas that's what it is it's a pyruvate kinas so the enzyme involved in this this step right here for glycolysis this one here is called pyruvate pyruvate kinas and he we're going to have a good discussion on him because he's highly
26:06
regulated okay and again this step is not reversible you can't go back through this enzyme so pyu kyes is doing what he's taking the phosphate from the phosphoenol pyruvate and converting it right into pyruvate by transferring that phosphate from the phosph pyu onto the ADP to make ATP but again let's just quickly say something here why am I getting two because there's two glyceride 3 phosphates there's two one three bis phosphoglycerates there's two three phosphoglycerates there's two two
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phosphoglycerates there's two peps or phosph pyate and there's going to be two of this last guy what is this last guy here called this last guy is called pyruvate which is our three carbon molecule that we've been looking to get to by this end point right so now this is our two pyruvates okay I'm liking it now one other thing that we need to mention what's the Des what's the the actual fate of pyic because he can actually divert into two different Pathways one is he can actually come
27:18
over here and he can get converted into this molecule the other one is he can go over here and get converted into another molecule now since we're only talking about olysis we're going to focus on what happens whenever we don't have oxygen and when we do have oxygen so let's say that this pathway is occurring during anerobic conditions anerobic conditions meaning no oxygen or very very little oxygen and over here this is going to be aerobic conditions meaning that you have
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oxygen there's plentiful amounts of it okay in a situation in which we don't have oxygen there's a s there's something bad happens I'm going to show you so you see these nadhs These nadhs are going to go and unload their hydrides onto specific molecules to take it to the electron transport chain and produce ATP but whenever we don't have oxygen these nadh is they have no choice but to unload those hydrides onto somebody their last choice to unload the hydrides on is pyruvate and what do they
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do these nadhs they come over here and they say say I can't deliver to the electron transport chain because I don't have anyone available to drop it off to and what happens he drops off those hydrides and gets converted into NAD positive so he gets oxidized but the pyruvate gets reduced and gains hydrides and gets converted into a molecule called lactic acid and you know what's happening here you know there's an enzyme a really cool enzyme involved in this step here look at this guy here
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okay he's got like six hairs on both sides soldiers are definitely retreating on this guy here okay what is this guy doing here this guy right here is involved in this reaction what is this enzyme called it's called lactate dehydrogenase why is this important okay this one is important and the reason why is because lactate dehydrogenase is a reversible enzyme but it's basically converting pyu into lactic acid what happens with this lactic acid a couple different things can happen with it
29:28
it can actually go to the liver and be converted into glucose eventually or it can go to the liver and be used to make ATP it all depends upon the body's demands but what's the other dangerous thing about lactic acid it's very acidic so it's going to actually cause the pH to decrease that was a heck of an arrow there sorry guys this is actually going to cause the pH to decrease it makes the the blood more acidic now one other thing is this has a lot of clinical correlation what do I
29:56
mean so you see that lact dehydrogenase enzyme if you do a blood plan on blood pan on somebody and you find that they have high lactate dehydrogenase levels what does that mean okay High lactate dehydrogenase I know that he's converting a lot of pyruvate into a lot of lactic acid wait doesn't that happen whenever there's no Oxygen or it's very anerobic yes so what does that mean then that means that this could be high in certain conditions in which you have maybe some type of Mi myocardial
30:26
infarction maybe you have like a necrotic bowel maybe you have a schia whatever it might be you could be having a lot of different situations where oxygen isn't being delivered to the tissues and because of that what's happening you're not getting oxygen to the tissues and your LDH levels are rising because you have to convert a lot of that pyruvate to lactic acid so you might have some metabolic acidosis also because lactic acid can actually decrease your pH and
30:51
make it acidic so you could actually might be seeing that in the anion gap okay so now let's go ahead and like count up everything that we basically generated from glycolysis so let's kind of tally up just a little bit of notes from this guys so first off we know that glycolysis is occurring where I didn't really tell you where it's occurring in the Cell It's actually occurring in the cytoplasm so all the fluid component of the cell so that's where it's occurring okay so that's occurring in the
31:15
cytoplasm of the cell the next thing that we mentioned is what is our starting substrate our starting substrate is glucose okay so we know that what glucose is R I'm going to kind of abbreviate this here here it's our starting substrate so I'm going to put SS starting substrate then we know that this is occurring in the cytoplasm what's our end product so what's the end product I'm going put EP for end product the end product is going to be two
31:47
pyruvates okay so I get two pyruvates out of this that's an end product what's some things that I produced which are byproducts of this whole this whole glycolytic process well I actually produced a total of a gross of 4 ATP but out of that since I actually used two of the four of those ATP in the beginning step with the actual glucokinase and also again with the fossil fructokinase I actually used 2 ATP so really I only net how much 2 ATP net okay now the next thing is with my nadh's I actually
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generated a total of two nadhs in this process so I generated two nadhs and the last thing that I want to mention for this is that this is an Anor robic process right generally it's an Anor robic process if we have no oxygen it generates lactic acid so generally this process is usually anerobic meaning low or no oxygen and then if that happens then what can you generate you generate lactic acid okay through fermentation processes okay so in in in short the skinny on it
33:15
is that glycolysis is occurring where it's occurring in the cytoplasm of the cell your starting substrate is glucose your end product is going to be two pyruvate molecules what are you going to have grossing 4 ATP but you used two out of the four ATP in this process so you only really net two ATP you generated two nadh's and it's an Anor robic process most of the time meaning that there's very little oxygen and if there is very little oxygen those nadh is unload into the pyruvate and convert
33:43
into lactic acid okay guys so in short that's basically the glycolysis pathway in the next video you guys are going to see something because what we're going to do is we didn't really talk about what happens when there's aerobic conditions in Aerobic situations this pyu at is going to get converted into another molecule which we'll talk about which is a two carbon molecule and this two carbon molecule will have a special thing on it called a COA group and this
34:10
is called acetyl COA and this is going to be called the transition step and that's what we will talk about in the next video when we go over the transition step reaction all right Engineers I hope all this made sense I hope you guys enjoyed it I know it was a lot of information thanks for sticking in there with me if you guys liked it please hit the like button subscribe and put a comment down in the comment section all right ninine nerds until next time
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