 Shall we go to the Calvin cycle? We're going to take a high energy electron carrier, and we're going to take the ATP. So essentially, the light reactions using photosystem 2 and photosystem 1 are producing the raw materials that we need in the Calvin cycle. So let's go check out, or let's go draw a picture of the Calvin cycle. It's a cycle. It's a cycle, which means that I'm going to draw it in a little circle. And what do you think is going to be the end game? We're going to take carbon dioxide gas, and we're going to roll carbon dioxide gas into a cycle. And this is the Calvin cycle. See what I see? Oh, whatever. So here is, when you take a gas and you make it into a solid organic compound, it's called fixation. So carbon fixation happens here. I guess I'll go like this. Because there's a very specific person. Okay, it's not a person. It's an enzyme that does this. So I'm going to make a little Pac-Man molecule because to show you that this little enzyme is in here. And this enzyme, seriously, if you wanted to give a most valuable player award to an enzyme in the system, it's got to go to this guy. Because without this enzyme, there would be no carbon to build a glucose molecule. And remember, our glucose molecule has six carbons in it. So this guy, his name, I mean her name, is Rubisco. And Rubisco walks in, yum-shla, or whatever. It doesn't really eat the carbon dioxide, grabs it, and it makes it into an organic molecule. I can't help it. I feel like I have to show you a picture of, yeah, that's a little boy, Melvin, Calvin. Melvin, Calvin, Melvin, Calvin. That's such a fantastic name. I might name my kid Melvin, Calvin, if I were going to have another kid come out of me, which I'm not going to do. So anyway, this is the Calvin cycle. You can see Rubisco is right here. We're taking the carbon dioxide. What, really? Look at all those things. Does it look familiar? Does it look like, oh, gosh, we could probably memorize all that? We totally could. So check it out. Just let's go back here and keep in mind that there's a whole bunch of chemical stuff going on. But I want you to know that we're using up ATP, because ATP is required to make this process happen, and ADP plus P is a byproduct. So you've got to have ATP. Who else? Who else would you say is necessary in this whole process? Hopefully, you're like, dude, the high-energy electron carrier is going to come in and get used up and then be just a car, an empty taxi, to go back to the light reactions and pick up some more electrons. It's backwards. Carbon dioxide goes in, ATP goes in, high-energy electron carriers go in, and glucose, this is where the magic happens, glucose comes out, and there's some sort of sugar, C6H12O6. So rubisco fixes the carbon. We use up all the stuff that came from the light reactions, and out of it, we get carbon-based sugar molecules. Seriously, like, does that blow your mind? It blows mine. I love that. All right, now let's look at why do we care? Photosynthesis is awesome. I mean, I could do this all day long, but in the big picture, why do we care about photosynthesis?