Introduction to Photosystems

by Jason Amores Sumpter
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in this video, we're going to begin our introduction to photo systems. And so photo systems are defined as complexes of pigments, proteins and other molecules as well that are found in the Fila coid membrane. And so recall from our previous lesson videos that these Thilo coins are the green pancake looking structures that air found inside of chloroplasts. And so to refresh your memory down below, over here on the left hand side, we're showing you the image of the chloroplasts organelles and recall that on the inside of these chloroplasts organelles are these green looking pancake structures that you see without and these green looking pancake structures are again called Fila Coy AIDS. And so, if we zoom into just one of these green looking pancake structures here, that is where we're going to find the photo system. And so notice in this image here, this is representing the membrane of the Thilo Coid. So we have the Thilo Coid membrane here on one side of the hill, a coid membrane. We have the Thilo Coid space, which is the inside of the Thilo Coid, the inside of the green pancake itself and then above the Thilo coid membrane. We have the stromal, which is just outside of the green pancake, but still inside of the chloroplast. And so notice that embedded within the Thilo coid membrane, this is where we find our photo system, This complex of pigments, proteins and other molecules found in the Thilo coid membrane. Now, photo systems are composed of several light harvesting complexes that surround a reaction center and notice that we have our light harvesting complexes color coded here in this purplish color which color codes to the purplish colors that we see down below. And we also have the reaction center up above. That's an orange that color codes of the reaction center that we have down below. And so if we take a look at our image down below, notice once again that here in purple, over here and over here we have this light harvesting complex so we could go ahead and label them as the light harvesting complexes and within the light harvesting complex, uh, noticed that, uh, I'm sorry. Surround the light harvesting complexes that you see here and over here on the right, notice that they're surrounding, uh, this center region here, which has the reaction center. You could see the reaction center is here in orange, right here in the middle, surrounded by light harvesting complexes as we described up above. And so, within the light harvesting complex, which will notice are the There are these teal circles and these teal circles here represent accessory pigments. And these accessory pigments are going to be helpful and absorbing photons of light. And so you can see photons of light here are interacting with the light harvesting complex, as its name implies, and it's able to interact with light because of these accessory pigments that absorb light. And so, if we take a look at the reaction center once again here in the middle, notice that the reaction center has these two green molecules right here that are chlorophyll a molecules, the predominant pigment found inside of chloroplasts on also notice that in red right here there is the primary electron, except which we'll get to talk more about later in our course. But for now, what we can see is that this photo system here is gonna be really, really important for absorbing light on allowing chloroplast to absorb light. And that's again because it contains accessory pigments, and it contains the predominant pigment chlorophyll egg. Now, as we move forward in our course, we'll get to talk Maura about photo systems and how they're involved and what's known as the light reaction, which again, we'll talk about Mawr in a later video later in our course. But what's important to note now is that most plants are actually going to have to photo systems, and these two photo systems once again are gonna be involved with performing the light reactions of photosynthesis, which again, we'll get to talk about these late reactions of photosynthesis later in our course. But for now, this is our brief introduction to photo systems. How photo systems are found inside of the membranes of Thill, a coid thes green pancake structures within chloroplasts and how photo systems are important for absorbing light and are involved with light reactions. So we'll be able to get some practice applying some of these concepts as we move forward in our course. So I'll see you all in our next video