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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 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway

Practice - Bioenergetics 1


Practice - Bioenergetics 1

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if you haven't yet tried. Question eight. Pause the video now and give it a shot. The five major features of Signal Transducer systems are specificity, amplification, modularity, adaption and, lastly, integration. Now the question asks for just these names. But let's talk about what each one means against the specificity is specificity, like we've seen with all the proteins we've looked at up to this point. Um, you know, these proteins have specific interactions. Uh, and the signals that they're using are generally chemical in nature amplification. Remember, like with our example of epinephrine. One molecule of epinephrine binding to a receptor can lead to 100,000 molecules of glucose writes. That signal can get super amplified, and it gets amplified basically each step of the way on the signal pathway. Modularity proteins are able to interact with multiple components of the pathway, right. They can interact with a the signal and also then interact with the receptor adaption. Right. These thes signal pathways are able to attenuate there. Response. Right. So you'll have some sort of feedback from the signaling pathway that, for example, will remove um and then, you know, using the example of epinephrine again you know where will have feedback that will actually remove epinephrine receptors from the membrane thio attenuate that sells response to the ligand epinephrine so thes signaling pathways adapt right. That's that's the important feature on then lasting integration. Remember that figure with all the different systems coming and intersecting? Remember talking about crosstalk? There's so many different signal pathways. They're all going on all at the same time. And those signals have to integrate together so that the cell comes up with the appropriate responses. Now let's flip our attention over to bio energetic six. So taking a look at question nine. If cake is greater than one and Delta G is negative for a particular reaction done, it's standard conditions. In which direction will the reaction proceed? Well, it will proceed forward and let's just take a look at this. So if we have cake greater than one, that means that remember cake. We're looking at the rate of formation of products over the rate of form, a rate of disappearance of reactant. So if there's a greater rate of formation of products, that means that our cake will be greater than one. However, if Arctic is less than one. That means that there was more. The rate of formation of reactant was greater than the rate of formation of products. Meaning that, um you know that the sort of the in terms of the kinetics of that reaction it's looking in the reverse direction. And lastly, if cake is equal to one, what do you think that means? What do you think it means if the rate of formation of our products is the same as the rate of formation of our reactant? Well, that means that we're equilibrium right now. It's important to also consider your delta. Geez, here. So, uh, if cake is greater than one and Delta G is negative or should put that out front actually write it makes more sense. Negative. Delta G. That means that you have a reaction that is going thio spontaneously. Proceed forward. So this is going to go forward. If your cake is equal to one new Delta G is equal to zero again, you are equilibrium. And lastly, if you're Delta G is positive and your cake use greater than our sorry less than one, you're going to go in the reverse direction. So in this case we have these conditions up top meaning or reactions going to proceed forward. All right, let's look a question 10. Which of the following is not correct? The answer here is E. Foster. Creating phosphor. Creatinine has a Delta G that's basically negative. 43 kill jewels per mole, meaning it's actually greater than that of ATP. Because ATP, you might recall, is about 30 killed. Jewels. Permal. So fossil creating actually has a, uh, a greater Delta G than ATP cream or negative Delta G. I should say on Yeah, a through D these air. All correct value ranges. Now let's take a look at Delta G on the reaction Student toast to Prada. Kate is negative. 35 killed jewels from per mole. This means that understand erred conditions. The reaction will. What does it mean if we have a negative Delta G. What is Delta G? Tell us about a reaction. It tells us whether or not reaction will occur spontaneously. It doesn't indicate how fast that reaction is going to proceed, though, so that's a big important difference to keep in mind that Delta G just tells you whether or not it's gonna happen spontaneously meaning. Whether or not it's gonna happen on its own doesn't mean it will happen quickly. There are a lot of spontaneous reactions that are incredibly slow. So our answer here is E will proceed spontaneously from student toast to Prada. Kate, if it was positive, then it would not occur spontaneously. And if it was zero, it would be an equilibrium. So let's move on to question 12. Which of the following has the largest negative value for Delta G of hydraulic assist? So this is very similar to question 10. Right now, we're almost doing the opposite of question 10 here. Right? So what has the largest negative value for hydraulic sis and of the molecules listed, it is acid and hydroids. And remember those range from about negative 32 negative 40 killer joules per mole, and that includes ATP. ATP is an acid anhydride. All right, let's take a look at question 13. So let's consider the mallet. Di hydrogen is reaction. We have a Delta G in the positive range in this reaction, takes mallet and 80 plus and turns into Axel acetate and n a d h. And we're actually gonna take a look at this reaction, much more detail in the next unit. We talk about citric acid cycle, but for now, looking at this, what is the answer here? The reaction, as written, may actually occur at some concentrations of substrates and products in certain cells. Now, remember back Thio are like Hollis ISS reactions. We had that one reaction that at these biochemical conditions Delta G Prime not it had a positive Delta G right, But it's cellular conditions. It's Delta G was closer to zero, right? So bear in mind that the reaction they're showing us, they're saying that Delta G. This is Delta Gina, our prime. Not, though that has a positive value, but it's possible we don't know. It's possible that in cells at certain concentrations of substrates and products, this Delta G might actually might actually be closer to zero or even negative. So it's we don't know that it can never occur can occur if it's coupled with a positive Delta G prime reaction, Um, and can occur right cannot occur at all because of its activation energy and does not even occur in bio context in a way so may occur depending on the conditions in the cell. And think about that reaction that we we talked about before. That had a positive Delta G in these conditions, but in cellular conditions actually had Delta G closer to zero. All right, let's flip the page.