 Hey everybody, Dr. O. This video we're going to talk about glycolysis. So like the name implies, glycolysis is the ripping or tearing part of a glucose. So glucose is C6H12O6, we're going to split the six carbon glucose into two three carbon pyruvate. So that's the beginning and that's the end. Other key things to note here, first of all, you will see I'll highlight some other areas as we go through, but there's a net gain of two Hp. We always talk about that. Other parts of your metabolism, we just talk about how many ATP are produced. Here we say there's a net gain of ATP, that's because what you see up around the screen, we have the energy consuming phase or the energy investment phase, then we have the energy payoff phase. So you actually spend two ATP to make four. That's why you see that term net gain of two ATP. Other key things to note, where is this happening? This is happening in the cytoplasm. So in your, in my and your cells, you know, 95% of our ATP is produced in the mitochondria. This is the other 5%. So what occurs out in the cytoplasm, the guts of the cell, same in bacteria, they obviously don't even have mitochondria. So location, the other key thing to note is it's anaerobic, which means this process does not require oxygen. That means even if you're doing aerobic exercise, part of your metabolism is anaerobic. The reason that's so important, we can't generate a ton of energy, but the reason that's important is because we can produce some energy when oxygen is short. So for intense bursts of physical activity, where you're trying to run away from an animal or, you know, nowadays it'd be exercise, but the system was designed to keep us alive. Uh, and then, or if you were in a lower oxygen environment, you can still generate some energy. So that's why it's important. You can't get a lot of energy, but you can get energy when oxygen supplies are limited. And then hopefully oxygen levels return to normal very soon. And we'll talk about more of that later. So anaerobic process in the cytoplasm, those are the key things. Then we'll talk about the end result there being pyruvate. This just, you can see the pictures a little bit better. So here's the energy investment phase. It does require two ATP. And I'll show you an even more detail why one of those is needed. But the key, the reason we do these first steps is first of all, um, we take energy to make sure glucose can't sneak out of the cell. We need the glucose to stay inside the cell, uh, obviously, so it can be used. So that's what we're going to spend a little bit of energy to do that. And then also we have to spend the energy to actually split the, uh, glucose in half. So those are the two steps that would require ATP. That's why we spend a two ATP, but you'll see that we make four in the second half here. So in the end, we are, we are spending two ATP to make four. That's where that net gain of two ATP comes from. I would never ask you if I asked how many ATPs are produced, it's never going to be four. It's always that net gain of two. But not only are we making two ATP, those two dollars, those two ATP dollars we can spend right now, but as you can see at the top of the screen, we are also making two NADHs. Remember NADH, NAD is an electron carrier that picks up electrons and protons, hydrogen ions, and as it does so becomes NADH. Each of these NADHs will be worth three ATP. So we've only made two ATP, but if we can, if we have enough oxygen and we continue down this cycle, we will actually be able to generate six more ATP once those NADHs reach the electron transport system. All right. So here's all the individual steps. I'm not asking you to memorize their structures or anything. I just want to show you the one key one to me is the first one actually. And so an enzyme called hexokinase is able to turn glucose into glucose-6-phosphate. So kinases are enzymes that add phosphates. That's where the phosphate comes from. The reason it's so important is this is what traps glucose inside your cell. Now it's called glucose-6-phosphate and it's actually not glucose, which means that as soon as glucose enters the cells, it becomes something else. That's important because there's glucose in your blood. As long as there's more glucose in your blood than in your cells, then glucose will be driven into your cells where it can be used for fuel. So if this first step doesn't happen, then glucose can leak out of the cell or glucose may stop entering the cell and then you're not making energy. So that's why I just wanted to highlight, like, I get it. You look at this and think, why would you ever need to know this? But there's interesting things that happen or maybe something to do with a prescription drug or something all along these pathways. That's just one really clear example. Without that step, we'd clearly be in trouble. So the first five steps would be the energy investment steps there and then the second five are going to be where you would generate those 4ATP and that's why you get that net gain of 2ATP. I think that's plenty to know about glycolysis. I hope this helps. Have a wonderful day. Be blessed.