Practice - Membrane Structure 2 - Video Tutorials & Practice Problems
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Practice - Membrane Structure 2
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if you haven't done question 27 yet. Paused the video Now, hopefully from the question on the previous page, you'll know that the answer is B because there is no fossil light based B one, you have a one A to C and D, and the reason there is no B is because be was actually renamed A to No question 28 is also quite similar to the one we saw in the previous page. So hopefully this one will be a breeze for you to solve. You do 25 over 7 50 and 75 over 80,000, and that gives you 0.3 repeating and 0. 9375 Divide those two numbers and you get 35. Ah, hydro pithy plot is used to predict whether given protein sequence contains membrane spanning segments and I hydro pithy plot, basically is a graph that looks kind of like this. Here's your zero point Here's your negative region and you're positive region of the graph and you're gonna just have this kind of crazy line like this that goes back and forth between the different regions, and basically the positive region is representing what is hydrophobic. The hydrophobic segments and the negative region is representing the hydro Filic segments. And what you more or less wanna do is you're looking again. Remember, 20 amino acids is, um is the minimum amount to span the membrane. So you're looking for window of about 20 amino acids, um, in the hydrophobic region, and you actually use, like, 7 to 20. But let's just say 20. And when you find something that fits the bill like that like, say this, for example, in our mock graph here say, Oh, that's a membrane spanning segment, all right, that's basically all there is to it. The fluidity of lipid bile air is increased. Bye. Sorry. By increasing the temperature, decreasing the number of unsaturated fatty acids with decreased solidity. Right? Unsaturated fatty acids increase membrane fluidity because they have lower melting points. Um, obviously decrease temperature. That's the opposite of what's true. Fluidity fluctuates with temperature increase on increasing the length of the alcohol chains will actually decrease fluid it because if you recall from lip, it's the length of the alcohol chain. Actually, um, the longer it is, the higher the melting point, so shorter chains will have lower melting point and will therefore, uh, make a more fluid membrane. And lastly, substituting on unsaturated fatty acid for a saturated fatty acid will increase the melting point of the um or the the molecule. The unsaturated molecule will have a much higher melting point than the saturated molecule. Therefore, putting the unsaturated molecule in will decrease fluidity. Lastly, peripheral membrane proteins are generally non co violently bound to membrane lipids. They basically that usually associate via hydrophobic interactions. Peripheral membrane proteins are not usually denatured when released from membranes, Um, because they're not deeply associated with the membrane there peripheral to the membrane. They can be released from membranes Onley by treatment of detergents. No, that's trans membrane proteins and may have functional units on both sides of the membrane. Absolutely not. Their peripheral meaning there on one side, right, one side or the other, not both, and penetrate deeply into the lipid Byler. No, they're very weakly associated with it. All right, let's flip debate
