in this video, we're going to begin our lesson on fermentation and anaerobic respiration. And so up until this point, in our course, we've really been focusing on aerobic cellular respiration in the presence of oxygen. But here in this video, we're going to address Well, what happens if Arabic organisms don't have any oxygen around well without oxygen, Arabic cellular respiration? As we've discussed it in our previous lesson, videos cannot occur. So aerobic cellular respiration can Onley occur if oxygen is present. But without oxygen, as the final electron except, er, the electron transport chain is gonna get backed up like a traffic jam. And ultimately, the amount of n a d. H is going to increase, whereas the amount of n a. D plus is going to decrease significantly down to dangerously low levels. And so if we take a look at our image down below the top half of this image notice that we have, like Collis, is here as the very first step of cellular respiration. And once again, if oxygen is present, then cellular respiration would occur as we've discussed it in our previous lesson videos where Pirated oxidation would occur. Then the crab cycle, then the electron transport chain in Kenya's Moses. But once again, these stages here are on Lee going to occur if oxygen is present. If there's no oxygen present, then these stages are not going to occur. And instead, if there's no oxygen, then fermentation is going to take place. And so the process of fermentation is a process that's going to use the electrons from these any DHS that have increased to reduce Piru of it and generate alternative molecules that end up regenerating N a. D Plus is that, uh, the N A D plus is have gotten dangerously, dangerously low. They've decreased really, really low. So one of the big takeaways of fermentation is that it's going to help regenerate those n a d Plus is that have gotten dangerously low now, depending on the specific type of organism, the pyro of it that gets reduced can be reduced to either lactic acid or it could be reduced to alcohol. And so later in our course will discuss lactic acid fermentation and alcohol fermentation as well. Now fermentation ultimately is going to make very, very little amounts of a teepee, and so really Onley, some uni cellular organisms can survive on just fermentation alone. But multi cellular organisms they cannot survive on just fermentation because it makes so little a teepee that it's not enough to drive the energy processes that are needed by multi cellular organisms. But fermentation is advantageous because it will allow for the regeneration of N A D plus, as we've already indicated, and that regeneration of any D plus is really critical to allow, like Kalle assists, to continue even in the absence of oxygen. And so even when there is no oxygen, like Collis is, is able to continue and produce the small amount of 80 p that it does because fermentation regenerates the n a d plus that it needs. So in order to get a better understanding of this, let's take a look at this image that we have down below. And so recall that once again, the electron carriers and a. D. H and F D H two s, they can be represented as these electron taxicabs and so notice. Here we have these electron taxicabs and all of these other electron carriers here that we're showing as these other vehicles, and so notice that what we're showing you here in this image is that there is no oxygen acting as the final electronic sector. And so when you take a look at this sign here, notice that it says specifically that the electron transport chain is backed up because there's no final electron except eR or no oxygen gas, uh, toe act as the final electron accepted. And so when there is no oxygen, what happens is the amount of N a d H is are going to increase significantly. And so the electron transport chain is gonna get backed up like a traffic jam. And so notice here, what we have is a traffic jam because there's no final Elektronik sector and there's no oxidative phosphor relation, which means there's not a lot of 80 p being generated when there's no oxygen. However, even when there's no oxygen, fermentation can take place. And so notice Over here we have this fermentation plant that has a sign that says, Hey, we'll empty your taxi to help glide colle Asus and make a little bit of a teepee just from like Collis. And so this electron carrier here, this electron taxicab is basically saying, Let's take this exit so that we can help out, like Collis Iss and help Glen Collis make a little bit of a teepee. And so the fermentation plant is able to take the N a. D H is that are being built up, and it's basically able to take those electrons. And it's able to reduce Piru bit to generate either lactic acid in some organisms or ethanol or alcohol in some other organisms. And so this is Ah, fermentation is going to regenerate the N a D plus or the empty taxi cab, and the empty taxi cab or N a D plus is needed. In order to allow Glide, Collis is to continue forward. And so the empty taxicab is going to, um, allow for glide. Collis is to take place and, like dialysis, is going to be able to produce a little bit of a teepee even when there's no oxygen gas and the n a. D. H s are backed up in this traffic jam. And so notice that this here is a loop that can continuously happened so that glide Colle Assis is able to continuously run even in the absence of oxygen. But once again, like Kallis is only produces a small amount of 80 p just to a tee pee molecules. And so Glen Collis is the amount of 80 p that it produces is not enough to allow multi cellular organisms like ourselves to survive in the absence of oxygen. And so, uh, this here really just shows how fermentation is critical to allowing, like Collis is to continue in the absence of oxygen. And so we'll get to talk even mawr about fermentation moving forward in our course when we talk about lactic acid fermentation and alcohol fermentation. But for now, this here concludes our introduction to what happens to Arabic organisms if there's no oxygen and how fermentation is going to take place when there is no oxygen. And so we'll be able to get some practice applying these concepts as we move forward in our course. So I'll see you all in our next video
