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Learn the toughest concepts covered in Biochemistry with step-by-step video tutorials and practice problems by world-class tutors

Review 1: Nucleic Acids, Lipids, & Membranes

Practice - Membrane Transport 2


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facilitated diffusion through biological membrane is driven by a difference in solute concentrations. If it were driven by ATP, what you'd have is primary active transport, and it is most certainly specific with regard. Thio substrate. Now the specificity of a potassium channel for potassium over sodium is mainly the result of the differential interaction of the selectivity filter of the protein. Now, considering this is an ion channel, it's unlikely that it would be hydrophobic that it would have a lot of Foss Philip bids or cholesterol, for that matter, because it's going thio want to be Hydro Felix so it can interact with the ions better. Now, let's do a bit of a throwback problem here, Thio, our friend. The enzyme kinetics problem. Except now we're masquerading it as a transport problem and looking for Katie instead of K m. So who? Everything's changed, right? But still, it's good to practice this because it could come up. So you're gonna want to solve this using a line Weaver Burke type plot, but we don't actually need to graph it. I'm just trying a representation of it here to talk about a couple things in case you forgot so this point right here. The Y intercept that is equal to one over V. Max. Right? And this point right here, the X intercept is equal to negative one over K m. Or in this case, Katie. So we don't actually need to graft this, But we do need to use some of the data and a little bit of math, and we're gonna have to get the reciprocal for some of these values. So this is gonna become five. This is gonna remain one. This will be 17.5, and this will be 13 and we're gonna need to use our y equals MX plus B equation or line. All right, so first things first, we need to find em the slope. And we're going to do that by determining the change in rise over change and run. So that is going to be 17 5 minus over five minus one, which is equal to four point 5/4 or 1. to 5. Now, To find B, we need to plug in some values to our equation. So let's do 13 equals 1.1 to times one plus B. So B is equal to 13 minus 1.1 to 5, which is equal to 11.87 five. And remember, that equals one over V. Max. It's not exactly what we want. What we want is be Max, So V Necks is going to be one over 11. which, it turns out, is equal to 0.84 micro moles her second. Now to find Katie, we need to substitute zero in for Why? So we're gonna say zero equals 1.1 to 5 x plus 11.875 which is B and we need to re arrange to get X by itself. So we get negative 11.87 5/1 0. to 5 equal to X and let me just scroll a little bit here so you can see this better. My head doesn't cut it off. Alright, So that is equal to X. And that comes out to about 10.6 or negative 10.6. Rather remember, that's equal to negative one over Katie. So Katie is going to be equal. Thio negative one over negative 10 6, which comes out to 0.94 millimeter. All right. Moving on to question 40. The type of membrane transport that uses ion radiance is the energy source is secondary active transport, primary active transport uses ATP secondary active transport uses thes Grady INTs often established due to primary active transport. Thes radiance air usually there because pumps are pumping things actively. Uhh! Passive transport relies on concentration Grady INTs and includes simple diffusion and facilitated diffusion. Alright, last problem. And this one is kind of an interesting one. So bear with me on the explanation. But here is how to think about it. If you let's say, have a membrane with three transporters in it. Right. And one transporter transports all amino acids, including licensing and Argentine. And then you have another transported that specific toe Argentine and another one that specific toe lie scene. And it turns out that this Argentine transporter is inhibited by lacing. And this listen transporter is inhibited by argentine. And by the way, this little symbol that I'm drawing right here um, it's kind of like perpendicular symbol kind of looking thing that Zatz what we use in neuroscience to mean inhibition. So I'm just saying that those are inhibiting those transporters. So anyways, if the Argentine transporters inhibited by life seen well, then Onley half the license gonna get through because it's going to have to go through this other transporter. And likewise, if on Lee, if the Argentine is inhibiting the slicing transporter, only half the license is gonna get through because it's gonna have to just use that other one. So that's why the answer to this question is three. That's all I have for this video. If you have any questions, please leave comments on the videos and I will answer them and good luck on your exam.