so this is that hypoxia inducible factor that I told you about um that I was unaware of until the Nobel Prize was awarded and so there are direct oxygen sensors in the um in the cell and this is a protein this hypox not in the the nucleus and if oxygen is present it will it will spontaneously bind onto that protein and then it will cause that protein to be chopped up so if oxygen is present the hypoxygen concentration gets like 5% or below in a Cell then this won't happen adequately and and the hypox inducible factor concentration will build up and it will migrate into the nucleus the nucleus uh will then use that as a transcription factor to make new proteins that regulate cell Behavior some of those proteins might actually uh go outside of the cell and basically say hey we're not getting enough blood flow we're not getting enough oxygen so angiogenesis can occur what's angiogenesis yeah new formation of blood vessels so when doing endurance training this is part of endurance training this is why lactate threshold training is a common part of endurance training um doing too much pushing it too hard though will uh actually counter uh counter angiogenesis and it will cause more of an anerobic get decreased mitochondria decreased blood vessel um formation and cause some of the cells to switch on over more to an anabolic type mode which is not good this is why over training too hard in um in endurance training can actually lead to poor results and that's one of the harder things that a lot of people have especially if they're just coaching themselves is they have a tendency to push themselves too hard too much of the time um anyways off on a little bit of a tangent so you need to get that concentration just right for uh angiogenesis um so part of the reason why a Nobel Prize was awarded for it is because you know metastasis cancer um there are a variety of different Pathways that relate to cancer progression having to do with aerobic anerobic uh in particular anobi uh processes and then you know metabolic reprogramming that's going to depend on the tissue type it's going to depend a little bit on the cells how those cells are going to behave um based on this so there is a direct oxygen sensor it is not just the electron carrier concentration uh waiting and now that I think about it waiting until the electron carrier concentration gets too altered would not be very good for the cell and so this is going to be more sensitive than the NAD plus nadh concentration um which is what I had hypothesized was the regulatory mechanism and that's does not actually seem to be correct I was wrong many times but that one you know for more than a decade I was wrong um anyways any questions on this okay ongoing area of research um so then this transition step which is shown right here in this little top green circle this is the one that if there's oxygen at adequately available then the this metabolic pathway will occur so uh we'll get the taking of the pyruvate and convert it into acetal COA what was COA again Co yeah coin I a and what what's its role I used an analogy so when dealing with small things I think I talked about tying flies which like the analogies that I use sometimes people are like I can't relate to that so I don't know a good analogy that everyone can easily relate to but sometimes it's helpful when dealing with something small to have something bigger attached to it um and so it's it's a something that's attached that's reusable did you have a good analogy for meil like little adhesives okay I'm trying to picture that I've had okay okay cool um I'm yeah it's F no it's fine but the point is each person like sometimes when trying to understand something that's happening at a molecular level that is at a level we really have a hard time imagining it's helpful to think about how it might be sort of like things that we can relate to so that's all I'm trying to do here um so then the electron carriers that get formed by the actually which steps use your chart which steps of the central pathway do form electron carriers or if you already know it you don't have to use your chart so what are the three steps or the three major Pathways that make up the central pathway and which of those steps form electron carriers yeah so all three of them do okay all three of them do um and so the Glycolysis provides two nadh per glucose transition step causes two nadh per glucose and then the um kreb cycle does six nadh 2 fadh2 and these are I'm just doing the electron carriers here and so of course A lot of these do come from the kreb cycle which is very much in anerobic land or excuse me aerobic land I said that wrong uh so aerobic land means that you have to have adequate oxygen you have to have adequate mitochondrial function in order for those processes to occur so then these electron carriers they bring their electrons to the proteins that are on on this inner membrane of the mitochondria the electrons jump off and as they jump from a protein to protein they're pumping protons okay and what did I say I don't know if you remember about the the protons associated with the nadh and the fadh2 are they going to be involved in that pumping they might be it's really more about the electrons but there are hydrogen ions protons as well they might get pumped but they are certain not the sum total of the protons pumped there's a lot more protons pumped than are carried by the nadh so for an nadh the two electrons that jump onto the fmn protein and then go down this little energetic Cascade there may be 10 protons that are pumped okay why is it that fadh2 is worth less ATP the electrons it carries go on fewer of the pumps these electrons notice here it's it's on the co-enzyme Q here the fadh2 the electrons there they jump onto this and they have the opportunity to pump fewer protons by pumping fewer protons you have less of those protons to then run the ATP synthes that we're going to look at so is the ATP synthace part of the electron transport chain no but it's really easy to be confused and think that it is because it's closely associ with it without the ATP synthes the electron transport chain wouldn't do anything useful and without the electron transport chain the ATP synthes wouldn't have any protons to recharge ATP so they they work together but they're technically separate from one another what is the end result of the oxygen or excuse me I just told sort of told the answer what's the end result of the electrons so what does the oxygen do with those electrons it takes them and what happens oxygen turns into turns into water metabolic water so the the electrons that we tear off of glucose and off of fat that get put on the electron carriers they go and pump a whole bunch of protons and then they end up on oxygen and turn into water the oxygen we breathe in turns into water I'm going to say that again because that's not the way most of us think it works CU oxygen that breathe in and use gets turned into water it does not get turned into carbon dioxide and most of us want it to turn into carbon dioxide because oxygen comes in carbon dioxide goes out carbon dioxide has oxygen on it it seems like you could just take that oxygen and put it on a carbon and that's how you get carbon dioxide from oxygen and that's not actually how it works how do we know this well I'll tell you they've radiol labeled it you can use radioactive isotopes of oxygen Andor carbon and keep track of where they go so they've actually been able to directly assess this okay so where does the carbon dioxide come from yeah it's the carbon in the glucose or the carbon in the fats that we're burning right now it appears that most of us are pretty low metabolic rate we're not sprinting we're not you know doing heavy lifting or anything like that so probably 60 70% of our calories are coming from lipids right now okay to keep ourselves running and um as we tear that those lipids apart uh that's how we produce carbon dioxide so just a quick reminder electron transport chain this this is a representation of it um this is the inner membrane of the mitochondria um those of you who had micro or will be taking micro this inner membrane of the mitochondria is the equivalent of most bacterial plasma membranes the outer membrane is the equivalent of a um lome or vesicle around that and so it's one that's actually made by the host cell I'm talking about something called the endosymbiotic theory of eukariotic cells but anyways um so these protein complexes they're taking the electrons from our electron carriers and they're using that as an energy source to pump protons and the electrons will jump from one protein to another as it goes from a protein to the next it will be pumping protons um there may you know 10 protons pumped per electron set of electrons for nadh um there may be six pumped for fadh2 with fewer protons you have fewer less ability to make ATP the ATP synthase is not part of the electron transport chain itself but it uses the protons that have been concentrated here how could we measure that again we ended yeah it's just it is acid so this would if if it were to just stay here this would be very acidic um these protons then go down their concentration gradient as they go down they induce an electromagnetic flux and they cause this ATP synthes to spin and I'll show you on the next slide that the ATP synthase looks quite a bit different uh from this as it spins the protein can accept an ADP inorganic phosphate as it's spinning around the the protein just sort of does this it grabs new new reagents ADP inorganic phosphate and pushes them together and then throws them on out as ATP um that's sort of the mechanism it's more a little more complicated than that but I think that's adequately so here we go we've got our proton our protons here these protons go through they have a positive charge so they do act as an electrical moving charge it's not an electron it's the opposite of an electron um and this isn't just like an electric motor it essentially is a molecular electric motor it's just not using electrons it's using protons instead and we take the ADP and inorganic phosphate and we recharge it now quick side note um there is an area of discussion about how things come to be called intelligent design uh that has argued that you know things in living systems are too complicated to have come about uh by chance and therefore someone or something must have created it this is one of the examples that's often given that all of these parts if we get into the detail of these parts in order for them to work to recharge ATP each of these protein subunits would have need to evolve separately and the Assumption um with the intelligent design argument is that there's no way that that could have happened by chance and that the other assumption which happens to be the one that's incorrect is that without them being in exactly this configuration they have no use and we actually know that the um section here that allows the proton to go through it can act as a pump in certain types of bacteria uh the rotor has certain functions that can be used in other situations other than in an ATP synthes uh and so it basically has been shown that these parts can either be used to make an ATP synthes or they can be used to make a variety of other useful proteins without them being assembled in this um in this configuration anyways I possibly answered a question that you've never thought about and totally don't care about but for some people that's sort of a big deal as far as the the conversation um I do have this protein image flipped upside down and the purpose of that is just to make it mirror the one on the right so yes the symbols are upside down you're not you're not hallucinating that um but this is uh what's called a back a cartoon backbone view of the proteins here uh on the left hand side so this is that slide 13 I think it was actually slide 12 up until recently um that shows our our Central pathway of metabolism which includes glycolysis P um transition step and kreb cycle I do say that transition step is a single step there are some arguments that it could be considered two or three steps as far as the different pieces and I just want to point that out glycolysis I say is 10 steps there's an argument for 11 steps as well I don't really care that much one way or another about the number of steps I'm just trying to indicate hey there are several steps along the way and most of the time if we have normal or I should say typical genetics and typical function of the pathway it's going to start with glucose and end with two pyruvates with the transition step it's going to start with two pyruvates and it's going to end with acetal COA and then with the kreb cycle also known as the tri carboxilic acid cycle citric acid cycle we're going to start with two acetal groups I'm going to ignore the COA for right now and we're going to end up just with carbon dioxide and then on the right here it shows the energy carrying molecules that are recharged so notice I have at P here that does not cross the electron transport chain when we've got substrate level phosphorilation an inorganic phosphate that gets put on an ATP or to make an ATP that happens right at the location of the chemical reaction whereas with the electron carriers those electron carriers are right there at the chemical reaction occurring and then they migrate to those proteins in the electron transport chain give up their electrons and then the ATP is made l later on through the ATP synthase okay so the traditional numbers which you know these were done oh 50 years ago 60 years ago uh they have been reworked uh there are some new experiments probably 15 20 years ago where they found out that the nadh and the fdh just weren't quite as efficient and it has to do with the number of protons pumped and then the number of prot you need to go through the ATP synas to recharge an ATP so you may Wonder well how is it that you can end up with you know 2 and a half ATP for an nadh well if an nadh pumps will say 10 protons and then it takes about three protons to make an ATP then you'd get approximately three ATP per nadh but if it takes five or uh if you if it pumps 10 but it takes five protons no excuse me takes four protons if I can do some math here then you get about two and a half and so it has to do with the number of um protons pumped versus the number of protons going through the ATP synthes to make an ATP and it's that ratio and all of this is theoretical maximum and so in a given cell it's probably not going to actually be this efficient if we were for the traditional numbers if we were to add all of these up the two plus the six plus the six so that's 14 right there plus plus another 6 is 20 26 32 36 and you're like okay that's what there but wait a sec there's another two here 38 why is it he's saying Max gross is 36 when really if you do the the molecular accounting it looks like it should be 38 well there are some pumps in the mitochondria that use ATP to move things around and so it's not as efficient as what we can do on a piece of paper the idea is that we can break this up into pieces and get it get some sense of where the energy is coming from which Pathways produce the most energy and you can see that it's the highly aerobic Pathways of the KB cycle that produce most of the ATP this will be relevant when we in lab talk about things like um Atkins diet and other low carbohydrate diets um that try and put people into keto hopefully not keto acidosis but into ketosis and then they do have the ability to essentially pee out calories which can lead to you know pretty rapid weight loss there are some reasons why it's not a great idea um it's not sustainable for most people at least and so we'll talk a little bit about that in lab so anys with the newer numbers just the only thing I want you to know with the newer numbers is that it's not quite as efficient as the original old numbers if you're doing calculations most of the textbooks most instructors that I've chatted with they have continued to use the traditional numbers even though we know that it's not that efficient just because it's literally been around for many decades longer these these numbers any questions on that okay are you guys enjoying the molecular counting of the chemistry of the cells I used to hate it to tell you the truth so I'm enjoying it more now okay so now we need to start zooming out beyond the central pathway and figure out what things can connect in into the central pathway so um this is also looking at overall physiology because we're not just talking about a set of molecules in a single cell but molecules need to be shuttled around to different parts of the body so we can have we can digest um food and have blood glucose we can then bring that on in um I talked about the pumping in of glucose so the insulin receptor in most cells will open up this little channel the glucose will come in and then because the hexokinase enzyme um will phosphorate it effectively the concentration of the blood glucose inside a cell is always right near what cells in general have what concentration of glucose in them if immediately a glucose comes into the cell and it turns into something else pretty darn close to zero which means there will always be a concentration gradient okay so as long as you open the channel glucose will have a tendency to come into the cell because it gets turned into something else that can't go back out through the channel um and so then this glucose 6 phosphate it can either be burned through glycolysis and we can use it for energy or if we've got excess in the uh liver or in the skeletal muscle or for temporary storage in some um intestinal cells we can uh take this glucose 6 phosphate make a little hop the phosphate on over to a different spot on the glucose and then start to store it as glycogen glycogen is a uh way of storing carbohydrates it's it allows for really fast metabolic conversions from the stored form of glucose to dumping it into the bloodstream the downside a lot of water glucose is very hydrophilic so as you make bigger and bigger glycogen there has to be water associated with that there are bodybuilders that I'm aware of who have actually used this to their advantage so part of the process of bodybuilding and then um competing in bodybuilding competitions is not only doing things to make muscles bigger and body fat lower and all that but also at the time of the competition to look as big and buff as possible and so um they actually use what used to be used for endurance athletes something called glycogen loading um we now know that glycogen loading isn't as helpful for endurance athletes as we thought it was for a long time but um bodybuilders will do it they will decrease couple you know maybe a week week and a half before a competition they'll decrease carbs get their metabolic systems actually making carbohydrates and then a couple days before a competition just sort of gorge on carbohydrates some of those carbohydrates will go to lipids but because of the prior activity of not uh eating carbs there's a general movement to break down lipids not to make lipids so you get a lot more storage of carbohydrates and some of that will end up you need to keep working out lightly to get the carbohydrates in the muscles more glycogen will be in skeletal muscle which means more water which means bigger muscles okay how does it compete with using anabolic steroids H probably not super well but there are some um bodybuilders who feel like it can give them an edge if you're not aware of bodybuilder eating habits most of them are atrocious they can be very very strict and then they have a competition and then all hell breaks loose in fast food restaurants and other places right afterwards anyways um so if we have a lot more nutrients that are available than what we need we can take obviously lipids can directly be stored in atpo sites lipids can be used by cells amino acids can be used by cells carbohydrates can be used in cells carbo EXT excess carbohydrates can be stored in skel muscle and hepatocytes but if we have even more than what can be stored by body cells and then the liver and the skeletal muscle everything gets converted to fat and that's something that I think many of us are aware of that it doesn't matter whether we have excess amino acids or carbohydrates or lipids all of it can shift on over to fat and there's getting to be more and more evidence that you know people gorging on carbohydrates can lead to atopos and of those probably fructose is the worst offender okay fructose physiology is such that it doesn't require insulin to regulate it and it just goes into cells and it causes adapost formation um and that's a big deal because it wasn't until the late 80s early 90s that high fructose corn syrup the ability to take glucose and turn it into fructose U became an industrial process and so a lot of us are exposed to a lot more fructose than is natural and it can mess with our physiology now there is a hormone called leptin the ocytes are supposed to release and basically they say we're full you're full you don't need to take in more calories and for some people that works well and for other people it does not work well it also will regulate metabolic rate as well um and so altered leptin physiology altered atopos site physiology um can cause issues with both appetite with metabolic rate and then with adapost formation