Activated Carriers - Video Tutorials & Practice Problems
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Activated Carriers
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Hello everyone in this lesson. We are going to be talking about activated carriers and how energy is exchanged between different chemical processes inside of the cell. Okay so we all know that cells need energy to survive and do all of the different biological reactions that they have to do now. How does this actually happen while energy is going to be delivered to the cell and transported around the cell And between chemical reactions via activated carriers. So energetically favorable and unfavorable reactions can be coupled together because that free energy that is released from one reaction can then be used to fuel the second reaction. So this is commonly called reaction coupling or simply just coupling. And it is defined as using energy using energy from one reaction to fuel another. Generally the reaction that provides the energy is going to have a negative delta G. It's going to be a spontaneous reaction that releases energy and then all of that energy that was released from the chemical reaction is going to be put into a positive delta G. Reaction which is going to require energy to function now. How does this energy actually move around? It isn't really just spit out and then used. It's actually gonna need carriers to get that energy from place to place. And these are gonna be called activated carriers and they are going to be small molecules responsible for energy storage and electron transfer. Remember electrons have energy and they can be utilized to provide energy to chemical reactions. So you'll commonly hear activated carriers also be called electron carriers if they actually do carry energy in that form. Now these are going to contain rich covalin it bonds and these bonds in activated carriers are broken and the energy is released. And then that energy is going to be used to fuel the next reaction. So energetic coupling is the foundation for cellular metabolism. It is going to be the way that we actually move energy around the cell and from different chemical reactions. So so that all of these different things can happen at the same time and in the same rate and at a nice continuous pace of life. So a great example of an activated carrier is going to be one particular molecule that I'm sure you have all heard before and we are all familiar with and that is going to be the marvelous A. T. P. It is going to carry energy right? Whenever we talk about A. T. P. We all say it is the energy molecule of the cell or energy carrying molecule of the cell. And that is because it is one of the activated carriers that we just talked about. It's going to be the most famous one. You're going to hear it. A ton. You're going to talk about A T. P. And its ability to carry energy all the time. So it is an activated carrier that is going to provide energy to unfavorable reactions. So A T. P. Is going to be a denizen triphosphate. It's going to have three phosphate groups attached to it. So that's the A. T. P. Part here. And then whenever you break off one of those phosphate groups it releases energy every time you break off one of those phosphate groups. And when you break off one of those phosphate groups that's going to be a favorable reaction and you release energy. So let me write that down, you release energy in this reaction. So whenever you break off that phosphate group which is right here. Whenever you break it off, energy comes out of that breaking of those covalin bonds. Now that turns a dentist seen tri phosphate from having three phosphates to having two. And now it's going to be called a dentist di phosphate or A D. P. So energy is released from A T. P. Turning into A D. P. And then this energy is going to be put towards a different unfavorable reaction. And unfavorable means that it needs energy. So it requires energy to do whatever it may do. There's gonna be tons of reactions that require energy inside of our cells. So this is just a generic example. But let's say that you have these two molecules that the cell wants to turn into these two molecules but that reaction is not spontaneous. It's not just going to happen on its own. So the cell is going to have to put in energy into this reaction. And it's commonly going to utilize a T. P. And the breaking down of a. T. P. To do this process. So a great example of this would be if you wanted to transport a particular molecules across the cell membrane against its concentration gradient, that's going to require energy because the molecule can't simply get across the cell membrane and it's going to go against its concentration gradient. This is very difficult to do because this is not going to happen spontaneously. The cell takes A T. P. And gives it to a transport protein. And then that transport protein utilizes the energy to move that molecule. So that would be a great example of one reaction requiring energy, the transportation of a molecule and one reaction releasing energy 80 P. Turning into ADP. So then that transport protein simply uses the energy from a TP to move that molecules. So that's a great example of ourselves using those A T. P. S. And if you want more information on that, we have a whole bunch of different lessons on cellular transport where we talk about those types of transport that require energy. But let's continue on. So now let's talk more about different types of activated carriers. I already talked about 80 P. But then there's also in A. D. H. And N. A. D. P. H. These are going to be the two most common activated carriers. So A T. P and N A. D. H. Are going to be the most common activated carriers. There's also another one you should know which is going to be F. A. D. H. And F A. D. H. Two. So those are also going to be different types of activated carriers. What we talk about those and things like cellular respiration and photosynthesis. So like I already said A T. P. Stands for a denizen triphosphate and it contains three high energy phosphate bonds. A. T. P. Is going to be generated via photosynthesis. We know this and cellular respiration. So all of this these processes cellular respiration which we do in ourselves and photosynthesis which plants do in their cells are going to generate these very important at p energy molecules. And when ATP is broken through hydraulic sis it releases that energy. Remember when one of those phosphate groups is broken off energy is going to be released. That energy can then be used for a different reaction. We also have in A. D. Plus. This in A. D. Plus molecule is going to be utilized to store energy and hydrogen atoms and electrons. So it is going to store high energy electrons. Remember how I said electrons can be used for energy in A. D. Plus is going to do that. It is going to gain electrons and it's going to lose electrons when in A. D. Plus gains and electron or when it is reduced it's going to turn into N. A. D. H. That is the energy carrying molecule. It has the electron inside of it and it has the energy. So this one right here this version has the energy This one does not no energy. So whenever in A. D. Plus accepts an electron it then turns into in A. D. H. And it now has energy which it can give to a different type of reaction. So it is reduced. Just remember that whenever in A. D. Plus gains an electron that's going to be reduction gain of electrons is reduction. And whenever in A. D. Plus loses that electron to a different reaction. Whenever it's powering a different reaction it is going to be oxidation. The loss of electrons is oxidation. Which you can remember with this nice little saying, leo says leo loss of electrons is oxidation gain of electrons is reduction. Okay so in A. D. Plus turns into an A. D. H. When it has that very energetic electron that is carrying. And then when it donates that energetic electron to another reaction to power that that reaction it turns back into N. A. D. Plus. Okay so now let's go down. And these are going to be some structural examples of in A. D. Plus. So this one right here is in A. D. Plus which is going to be a carrier that when it gets its electron becomes an activated energy carrier. Okay, so that's what N A. D. Plus looks like and this is what A T. P looks like. So this is a T. P. It has these three phosphate groups +123. And remember I told you that whenever you cut this one off, energy is released and this is going to be the process that we utilize to energize most of our chemical processes inside of our cells. And the reason it's called adenosine triphosphate is because it has an adenine base right here and it has three foss groups attached to it. I hope that was helpful. Remember activated carriers are going to carry energy and carry electrons which are going to be utilized to power other chemical reactions inside of the cell. Okay, everyone, let's go on to our next topic.
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Problem
Problem
Which of the following is false about activated carriers?
A
ATP and NADH/NADPH are common activated carriers
B
Activated carriers are responsible for energy storage
C
Activated carriers contain strong noncovalent bonds that are broken to release energy
D
Activated carriers can store high energy electrons
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Problem
Problem
NAD+ becomes NADH through which of the following processes?
A
Hydrolysis
B
Oxidation
C
Reduction
D
Condensation
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Problem
Problem
Enzymes bind to the transition state of the reactant because they have what?
A
The lowest kinetic energy
B
The highest kinetic energy
C
The lowest free energy
D
The highest free energy
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Problem
Problem
Which term describes enzyme regulation controlled through binding of a second molecule to a different site on the enzyme?
