<p>so a diglyceride is like a phopholipid without the head…?</p>
<p>he said that in the lecture, so yeah pretty much</p>
<p>enzyme cooperativity? what the heck is that</p>
<p>that involves the sigmoidal curve thing. it occurs in enzymes that have quaternary structure. basically, when one subunit binds to a substrate, it signals the other subunits to be more readily able to bind to subsequent substrates. This results in a curve that starts out slow, and then rapidly increases.</p>
<p>did anyone happen to read about the cytoskeleton?</p>
<p>it signals the other subunits on that same enzyme you mean? or it signals other subunits on different enzymes?</p>
<p>edit: crap, i have to do that reading. i bet wiki will be enough though, it’s going to be a very basic question from wut i have heard.</p>
<p>other subunits on that same enzyme.</p>
<p>when you’re talking about the fluidity of a membrane, are you talking about the mobility of both the proteins and the phospholipid bilayer? i think the answer to that should be yes right?</p>
<p>what are ribozymes? are they just enzymes that do something particular for RNA?</p>
<p>yes, fluidity refers to the movement of anything along the membrane.</p>
<p>malkin said that we don’t have to know those in detail</p>
<p>but they ARE RNA from what i understand that act as enzymes.</p>
<p>edit:</p>
<p>hey jb, what time are you staying up until? you’re really helpful lol</p>
<p>edit2:</p>
<p>okay checked my notes, ribozymes = RNA that act as biological catalysts</p>
<p>i was wrong calling them enzymes, because enzymes refer specifically to proteins</p>
<p>haha thanks, you are too.</p>
<p>i’ll probably only be up for another hour max. it’s been quite a long day.</p>
<p>damn, i think i’ll be up all night just reviewing and reviewing lol</p>
<p>i know the carrier proteins involved in active transport are uniport, symport, and antiport. </p>
<p>are these the same types of carrier proteins involved in facilitated diffusion though?</p>
<p>i was doing one of the practice tests late last night and when i went back this afternoon to go through my answers, i missed a lot of simple questions towards the end because i was half asleep and not thinking clearly. i wanna make sure that doesn’t happen to me tomorrow.</p>
<p>plus, i need all the sleep i can get now…i have 4 midterms next week. ■■■.</p>
<p>yes. facilitated diffusion can be channels or carriers as long as it goes with the gradient.</p>
<p>for me i just stay up all night before a midterm and then take 200mg of caffeine before going LOL. although last semester when i did this for my statfs midterm i was trembling/twitching/shaking for 10 mins when the midterm started though rofl</p>
<p>i don’t get how feedback inhibition has to do with allosteric regulation. i get allosteric regulation, and i get feedback inhibition. just not how they relate. do they even relate at all? maybe my notes are just wrong.</p>
<p>i wondered about that too earlier.</p>
<p>but here is what Dr. Malkin said about. maybe we can figure something out.</p>
<p>“So what the cell is doing is that it’s stopping making a bunch of compounds that are obviously costing it energy by inhibiting a pathway at the initial step of that pathway by what is known as feedback inhibition. It is very clever, very simple, and also involves the allosteric inhibition of the first enzyme in this pathway.”</p>
<p>then below he drew that picture A -> B -> C -> D -> E & F, using E to allosterically regulate the enzyme used for A -> B. </p>
<p>hm, actually just now as i was typing this i think i get it.</p>
<p>the difference between allosteric regulation and non-competitive inhibition is that an INHIBITOR in allosteric regulation will not stop the activity of the enzyme completely, but a non-competitive inhibitor WILL. </p>
<p>so E allosterically regulates the enzyme that catalyzes A -> B, meaning it will SLOW it down but not stop it completely.</p>
<p>tell me if that makes sense. </p>
<p>the key point is knowing the difference between allosteric regulation and non-competitive inhibition. i asked a GSI about this earlier today and he made it clear.</p>
<p>So in feedback inhibition, the formation of products isn’t stopped completely? It’s only inhibited? Wouldn’t it make more sense for the pathway to be stopped completely if there are already enough products present?</p>