Delivered on: 16 OCT 2023
In this lecture, we will explore the structure of the thylakoid membrane, focusing on the topics about: phospholipid bilayer, four major integral proteins in thylakoid membrane and the concept of electron carriers & electron acceptors.
Video Transcript:
Okay this is another representation of it. okay so this is a schematic diagram of it. Remember this is thylakoid membrane. Phospholipid bilayer.
Why is called phospholipid that thing just now it's called phosphatidylcholine, you got your head here you got your neck here you got your tail here. okay so the head here is the phosphate, in the middle here you got your glycerol, and the tail here you got your CH CH CH, the hydrocarbon tail right so that's why the membrane is called phospholipid. Phospho referring to the Head lipid referring to the glycerol phospholipid bilayer. Two layers of it okay and in between this phospholipid bilayer there are integral protein. These are the integral protein PS2 protein PS1 protein cytochrome b6f protein and also the ATP synthase protein.
Okay you can see that they are arranged in a vectorial way. Meaning that in sequence in the right positioning. you are not going to find this PS2 protein in between cytochrome and PS1 you're not going to find it because the energy moves from here to here that's how.
If the water flow from the waterfall to the river to the sea following the gravity this thing is follow the energy transfer from the high energy to the low energy. Meaning that when you are talking about the energy content of it, this side of the membrane dealing with higher energy because they just receive it fresh from the sunlight. High energy as you go further to this side less amount of energy.
Okay right have you seen this before? This diagram of course you have.
Stroma the soup of it, now learn another thing which is lumen not Lumos that's light. Lumen is the inside of the thylakoid membrane, so you got your membrane here the inside of it.
Yeah it's kind of like your your intestine. The inner of your intestine that is the Lumen where you got all your villi your microbes bacteria and so on. The outside of it is the rest of it. Okay right so four proteins please do not forget that.
Down the line I know we're going to see it in a bit but I'll just give you the pre head up about the terminologies. You're going to see this thing as well PQ, PH, PC, FD, FNR. So this thing we call as electron carrier. Okay there there's two concepts in in Biochemistry when it comes to molecule. A molecule can become an electron carrier or electron acceptor. If the molecule only accept electron and be done with it for example like this one here and NADP+ here, it accepts electron and then add hydrogen to it to become NADPH, we call NADP is an electron acceptor okay. However, when a compound for example like PQ here which stands for plastoquinone, not only that it accepts, but it actually move and transfer the electron to somebody else that we call electron carrier. So plastoquinone electron carrier, plastocyanin electron carrier, but NADP electron acceptor.
Okay, look at this membrane here even though the is image here is static because I can't find the one which is animated, this this thing this blocks of electrons carrier they are actually moving okay they move actually about tenth of nanometer. they move in the membrane because the membrane is fluid they move. When they get something, they move because they need to move the electron okay because electron cannot suddenly jump this is not you are spearing something it has to physically be closer to the target so that the electron can get transferred right, we'll see that in in a bit.
Reference book: Plant Physiology and Development 7th Edition
by Lincoln Taiz, Ian Max Møller, Angus Murphy, Eduardo Zeiger
Full video: https://www.youtube.com/watch?v=dYs_TczAsM0
Attribution 4.0 International — CC BY 4.0 - Creative Commons
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