So this is the big picture. You know, this is the, this is sort of the function. This is the, this is what you should start by understanding. This is basically an unbalanced chemical equation, because it describes what goes into a process, what comes out of the process, and you should understand this before you get into the next level. That's the big picture. We're going to jump into the medium-sized picture next. But understand the big picture first. This medium-sized picture is going to break our big respiration down into three sets of reactions. And the first one is glycolysis. Glycosys. Glycosys, meaning splitting, glyco, meaning glucose. So that's what's going to happen. We're going to start by taking a glucose molecule. And so glucose enters the cell. Glucose transports bring glucose into the cell, where it's met by a whole bunch of enzymes. Some of those enzymes are able to grab onto a glucose and change it a little bit by adding a phosphate to it, making it into glucose six-phosphates. And then another enzyme can come along, and it is able to grab a glucose six-phosphate and change it into something else. This is going to happen like ten times. It's going to go through ten or eleven steps. And when it comes out, glucose, which has six carbons, is going to be broken into two molecules of pyruvic acid. And pyruvic acid has three carbons. So there are two of these. And so you'll notice that we started with something with six carbons. We ended up with two molecules that have three carbons each. So if you're doing the carbon bookkeeping, and I encourage you always to keep carbon bookkeeping in your mind, because it's a really useful way of keeping all this stuff straight. What you'll notice is that we took something that had six carbons, we broke it into two things that have three carbons, we haven't lost or gained any carbons. Everything is accounted for. And what's more, it's like we took something and broke it in half, and that actually sort of is exactly what happened. We took something with six carbons, and somewhere along the way, we broke one of those carbon-carbon bonds, and ended up with two things that have three carbons. So when you break a carbon-carbon bond, the energy that was in that carbon-carbon bond is released. And the whole set of processes, it doesn't happen in a really tidy way, but the whole set of processes, and in this case, like calluses, is able to use that energy and to make some high energy molecules. So in this case, we get to take a couple of ADPs and turn them into two ATPs. Now, actually what happens is, like calluses, use as a couple of ATPs, but produces four ATPs, so we net two ATPs. But since this is just an introductory biology kind of lecture, it's not a biochemistry class. I'm not really going to go into it, but I sort of do encourage that, but I sort of do encourage you to look up like calluses, and to look through some of the descriptions of the actual reactions. It's kind of interesting, it gives you a better idea of what's going on, and even if something's going over your head, you'll still get something out of it. Anyway, we get to make two ATPs, but we're also going to turn two NADs into two NADHs, like calluses. As you're studying this for an introductory level class, this is how you should learn all these processes. What goes in, what comes out? So what goes in is glucose, some NADs, some ADPs. What comes out are some NADHs, some ATPs, and a couple of pyruvate acids.