 So photosynthesis has three main stages or parts and we're going to do, I'm going to show you what those parts are and then we're going to look at how a photosystem comes into the mix. First of all, you have what are known as the light reactions and these include the photosystems. Two photosystems, photosystem two, of course, and photosystem one. And then the products of both of those go into the so-called dark reactions, which do not necessarily take place in the dark and that includes the Calvin cycle. We're going to start our process by looking at photosystem one. I'm going to draw you a picture of a photosystem so that you can visualize again like, what is this and where is this happening? Photosystems are found embedded in the wall of a thylakoid. So I'm going to go like this, not in the wall of the chloroplast, the total chloroplast, it's in the wall of the thylakoid. So this is the thylakoid space. Are you cool with that? And I'm just going to blow this up a little bit. A space is relevant, but I'm going to blow up, I'm sorry because I just can't help it. I'm going to blow it up like this. That rat-her, that box is rat-her. And let's do, let's make my, this is actually my little photosystem visual here for you. And so I'm going to make a dot in here so you can see that, oh yeah, that's the photosystem. And this is my stroma, which was basically the chloroplast cytoplasm, and this is my thylakoid space. Okay, so are you oriented to what I'm looking at? The photosystem itself is nothing more than a bunch of pigments including chlorophyll and others that are embedded and set up to essentially, this is how I visualize it, they're essentially set up to funnel energy into this like center, like a reaction center of the photosystem. So sunlight energy gets funneled by a photosystem into the pit and then I'm going to tell you what happens, we're going to look at, you know, awesome, but what happens inside that pit and why is this even relevant? I draw it like this, this is totally not an accurate like depiction of a photosystem, but I draw it like this because I can imagine like little photons of light coming in and being captured and like being funneled, really truly funneled into the middle and then all that light energy is collected and you will see the amazing thing that happens when we do this. All right, let's start looking at photosystem 2.