Absorption Spectrum of Photosynthesis

by Jason Amores Sumpter
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and this video were briefly going to talk about the absorption spectrum of photosynthesis. And so an absorption spectrum is really just a graph that shows the light absorption of pigment molecules and so down below notice that we're showing you a pigment light absorption spectrum and so notice that we have on the Y axis the absorption of light so low on the Y axis represents a low amount of light being absorbed and high on the Y axis represent, ah, lot of light being absorbed and then down below on the x axis. Notice that we have the particular wavelength of light and nanometers, essentially just showing you the, uh visible wavelength of light here. And so it's important to note is that on this particular spectrum, we're showing you the curves for three different pigments. We're showing you chlorophyll, a in green chlorophyll be here and yellow and the carotenoids here in the oranges. Dark oranges color here, and so you can see the spectrums for each of these curves throughout here. And, uh, you can see these curves throughout, and so it's important to note eyes that these curves are just showing the amount of light that's being absorbed at a particular wavelength. And so what you'll notice is that wavelengths that fall into this region right here are mainly being absorbed. And so you can see this region here having the absorbed label. Um And then you can also see that wavelengths over here in this region are also mainly being absorbed. Um, not by all of the pigments, but by the collection of them together. But what you'll notice is that right here in this region, most of these wavelengths basically greenish and yellowish, they're not really being absorbed. And so, for our purposes here, we can just basically assume that these wavelengths here are being reflected so we can go ahead and say that these are being reflected here in this middle region from here to here. Since there's not a lot of peaks here, there's not a lot of absorption going on, so they're being reflected. And so really, that's the biggest take away here is that different pigments are going to absorb and reflect different wavelengths of light, but collectively it's going to be the amount of them and the particular wavelengths of light that are reflected that dictates the colors that we end up seeing in the plants. And so this year concludes our brief introduction to an absorption spectrum, and we'll be able to get some practice as we move along in our course, So I'll see you all in our next video.