Oxidation of Fatty Acids - Video Tutorials & Practice Problems
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concept
Oxidation of Fatty Acids Concept 1
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In this video, we'll take a look at the first phase when it comes to fatty acid oxidation. Now, phase A is our activation step and we're gonna say similar to glycolysis, fatty acid activation is an energy consuming step. The enzyme that we have to utilize is our acyl coa synthese. Here catalyzes the conversion of fatty acid to fatty acyl coa. Now when it comes to a synthetase, this is an enzyme that catalyzes a synthesis reaction. And unlike a sin face, this requires energy from a TP, right? So that's the difference between the two. This one here would not. Now, here we have one A TP is hydrolyzed to one A MP and two inorganic phosphates. So this is equivalent to having two A TP becoming two AD P. If we look at our overall reaction here, we have our fatty acid which is gonna become activated. We have our coenzyme A here with its file group exposed A TP becomes A MP because we require two inorganic phosphates being produced. Again, we're using our ayase uh enzyme to do this. And then here is our activated fatty acid as a product. So just remember phase A is activation when it comes to fatty acid oxidation.
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concept
Oxidation of Fatty Acids Concept 2
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Now, the second phase of fatty acid oxidation is our transport phase. Here, we're going to say that our fatty isaoa cannot directly cross the mitochondrial membrane. So if we take a look at this image here, we have our cytosol, we have our mitochondrial membranes. And in once we get past that, we get to our mitochondrial matrix. Here, we're going to say here is our fatty acyl coa, it cannot traverse across a mitochondrial membrane. So to do this, we're gonna introduce carnitine here and it's the enzyme carnitine acyl transferase that transfers the fatty AA group from K A to carnitine. So here we see that K A now has been replaced. Well, this whole thing here has been replaced with our carnitine. Now that we have carnitine, it can traverse across the mitochondrial membrane. It has now entered the mitochondrial ma matrix. You were gonna say that fatty ay carnitine moves from the cytosol into the mitochondrial matrix. The fatty acid carnitine reacts with ka in the mitochondrial matrix to produce fatty acyl coa. So here, once it, the carnitine has moved into the matrix, it reacts with this coenzyme A here with its style group thus creating our fatty acyl coa that we needed. Carnitine is released in the process and it's free to exit the mitochondrial matrix pass through the mitochondrial membrane back into the cytosol to begin again. It can then react if it wants to with another uh fatty acyl coa and start the process again. Right. So just remember when it comes to transporting here, it's us converting our fatty acyl away into a carnitine. And we're using a carnitine shuttle to move from the cytosol to the mitochondrial matrix by crossing the mitochondrial membranes.
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example
Oxidation of Fatty Acids Example 1
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In this example, it says fatty acid activation requires hydrolysis while we have one A TP going to one A MP. How is this equivalent to 280 P to 280 P? Right? So here we're gonna say one A MP molecule carries an amount of energy equivalent to two ad P molecules. No, that's not true because this one will only have one energetic bond here. This would have two AD P molecules which is four energetic bonds. So that's not equivalent conversion of one A TP to one A MP requires cleavage of two high energy phospho and hydride bonds. That is true here, we have triphosphate and this is only monophosphate. We've lost two phosphates here. So that means we'd have to cut too high energy fossil and hydride bonds to do this hydrolysis of A TP to A MP is accompanied by oxidation of an electron. Curious such as N A DH. Here, here we're not talking about um oxidation in the state. We're talking about basically the cleaving of our fossil and hydride bonds. This has nothing to do with oxidation. So this would not work. And then d doesn't work either. We found out that B is the most reasonable answer in terms of this.
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concept
Oxidation of Fatty Acids Concept 3
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In this video, we'll take a big picture. Look at PC oxidation. When it comes to fatty acid oxidation, we're gonna say the beta oxidation pathway consists of four repeated reactions. We're gonna say it cleaves two carbons. So we're gonna have acetyl coa from the fatty acid chain in each cycle, we're gonna say here, one cycle of the pathway produces one fa DH 21 N A DH and one acetyl coa. If we take a look here, we have our fatty acid, we undergo these repeated uh reactions. So one cycle here, we produce fa DH two and N A DH as our energy molecules, high energy molecules, we're going to create a Cylco A over here. So two carbons. Notice that we started out with 2468 carbons here. But my, my fatty acid chain is now only six because two of them are part of the CTO Coe over here. So what I've done is I've shortened my fatty acid chain. So we have our fatty acid, we've shortened it through oxidation to produce acetyl coa. And then because we still have additional carbon on this chain, we could go through additional cycles here, we're looking at just one cycle that we are creating one fa DH, 21 N A DH, we're creating one acetylate and we have this shortened fatty acid.
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concept
Oxidation of Fatty Acids Concept 4
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In this video, we're gonna take a look at beta oxidation number one. Here, we're going to say the enzyme ay coa dehydrogenase removed two hydrogen atoms from alpha and beta carbon atoms. As a result of this, we're gonna create a double bond between the alpha and beta carbon atoms. Now, we're also gonna utilize F ad in order to do this. It's gonna be reduced in the process to create fa DH two. If we take a look here, we have our fatty aal coe. Remember the carbonel group is this c double Bondo, the carbon next to it is the alpha carbon and the carbon next to the alpha carbon is the beta carbon. Here we have F AD which gets reduced to fa DH two. We utilize our enzyme Ayo dehydrogenase. As a result of this, we create our trend in oil. Kuwait. The hydrogens would orient themselves trans to one another. So that's why it's trans you know K so this would be what we produce in beta oxidation number one in phase C of fatty acid oxidation
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concept
Oxidation of Fatty Acids Concept 5
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In this video, we're gonna take a look at the hydration step. Here. We're going to say that the enzyme inno ka hydra adds water to the alpha beta double bond. Here. It's going to place the hydroxyl group or oh group at the beta carbon. As a result of this, we're gonna say three hydroxy A Saw Ka is produced. So here's our trends in no koe hydro tase helps to add water. So water is gonna come in the water is split where the beta carbon gates, the oh group and the alpha gets the H here. If we were number this, the carbon carbon will be one, this will be two and the beta carbon will be carbon number three. That's why the name is three hydroxy. The oh group is on the beta carbon, which also serves as carbon number three, right. So this would represent what we produce in the hydration step of ac oxidation when it comes to fatty acid oxidation.
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example
Oxidation of Fatty Acids Example 2
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Here, it says we need to identify the alpha beta carbon atoms in the structure below and complete the reaction. So here is our carbonel group. Next to it is the alpha carbon that carbon would have two hydrogens next to the off would be our beta carbon, which also has two hydrogens. Over here, we have our carbon connected to our SK A. The alpha carbon would still have one hydrogen and loses one to continue making four bonds and have to form a double bond with the beta carbon, which also loses one hydrogen. Remember to show them tr to one another and then that beta carbon is still connected to this methyl group over here. So this would represent our product when it comes to the utilization of Acyl coa dehydrogenase. Now, remember we'd also have to use F AD here so that it becomes fa DH two in order to create this trans product here, right? So that's what we'd say in terms of the alpha beta carbons and the product form.
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concept
Oxidation of Fatty Acids Concept 6
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In this video, we're gonna take a look at beta oxidation number two. Here. The enzyme three hydroxy coa dehydrogenase catalyzes the oxidation of the beta hydroxyl group. Now, here, since we're oxidizing that hydroxyl group, it's gonna form a ketone at the beta carbon. We're gonna say in this process of oxidation, we're gonna utilize N ad positive, it gets reduced to N A DH. So if we take a look here, we have three hydroxy acyl coa, we utilize our enzyme three hydroxy acyl coa dehydrogenase. Remember the enzyme name is just the substrate followed by the class of enzyme. Since this is an oxidation, we're utilizing dehydrogenase using N ad positive in order to oxidize our substrate in the process, it gets reduced to N A DH. Now what happens here is we have this alcohol group. When we oxidize a secondary alcohol, we make a keto. So now it is a kone group, we're gonna say here because it is a ketone, it becomes a keto Asyl ka. And because it's on the beta carbon, it becomes more specifically a beta keto Asyl coa as our product for beta oxidation. Number two,
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concept
Oxidation of Fatty Acids Concept 7
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Here in this video, we'll take a look at the cleavage step. Here. We're gonna have bond cleavage where the enzyme beta keto A saw Ka. And we're gonna say thy lase cleaves the bond between the alpha and beta carbon atoms. Here, we're gonna say a shortened fatty acid or fatty acyl coa is formed. Also one acetyl coa is produced. So here we have our beta keto ayl coa remember beta because the ketone group is on the beta carbon. We're gonna cleave the bomb between the alpha and beta carbon. So here we have the squiggly line to represent this cutting. Here, we have our co a group with our exposed style group. The enzyme here, all it helps us to do is to split this up. So what we're gonna make is we're gonna have SK A here and then our hydrogen here. So we just created our fatty AA ko A and then here we have AC K A. Those would be our two products formed here. So remember this represents the bond cleavage here. We're talking about a cation, a fatty acid oxidation
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example
Oxidation of Fatty Acids Example 3
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Identify each of the following statements about beta oxidation as true for T or false f hydration of trans ino coa. And the second reaction of beta oxidation produces three hydroxy ayl coa. Yeah, that is true. The formation of beta keto coa from the oxidation of three hydroxy aya requires entity positive as the coenzyme. Yes, that is also true. It is an oxidation. So we're utilizing dehydrogenase but in order to help with facilitating the oxidation, we do use N ad A positive N A DNA D positive becomes N A DH when it gets reduced bond cleavage to produce an acetyl coa from beta keto Ay Coe is catalyzed by beta keto Ay Coe thola. Here that is also true. Finally, oxidation of the fatty aoc ka by fa DH two produces a cy double bond between alpha and beta carbon atoms. That's false. It doesn't create a cyst double bond, it creates a trans double bond. So out of these statements, only the fourth one, the last one is a false statement. The previous three are true.
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Problem
Problem
Which one of the following coenzymes is not a part of the β-oxidation pathway?
A
ATP
B
FADH2
C
CoQ
D
CoA
E
NADH
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concept
Oxidation of Fatty Acids Concept 8
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In this video, we'll take a look at the beta oxidation energy output. Here. We're going to say that the energy output of the beta oxidation depends on the number of carbon atoms in the fatty acid. And we're gonna say fatty acid activation has a one time expense of two A TPS. And we're gonna say each cycle leaves two carbons. And in addition to this, we're gonna say that for every one cycle, we'll have one fa DH two and one N A DH as our high energy molecules that are produced. If we take a look here, we have our fatty acid. Remember we have a one time expense of two A TPS. In order to activate it, this will transform it into my fatty acyl coa in terms of a formula, we could talk about the number of cycles involved. That's just the number of carbons divided by two minus one. In this example, here, we're gonna do three cycles. Each cycle produces one fa DH, two and one N A DH. And since we have three cycles, we're gonna make three of each. Now the number of acetyl coate that we would make is equal to the number of carbons divided by two. This particular fatty acid has eight carbon atoms. So we do eight, divided by two. So we should make four acetyl Coates. From this, we can fill out this chart on the right. So three cycles of beta oxidation, we're gonna say again, there's a cost one time cost of two A TPS. We're doing three cycles. So we should make three fa DH twos and three N A DH S. Since this is an eight carbon fatty acyl coa molecule, it'd be eight divided by two, giving us four acetyl coa as our end molecule. So remember this is just the setup when we talk about the energy output the energy cost when it comes to beta oxidation.
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example
Oxidation of Fatty Acids Example 4
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Here in this example question, it says Banic acid is a long chain fatty acid containing 22 carbon atoms. How many cycles of beta oxidation are required to completely degrade bionic acid? All right. So here they're asking us for the number of cycles. Now, recall if we're talking about the number of cycles. Well, that's just equal to the number of carbons divided by two minus one. We have 22 carbons involved divided by two minus one. That would be 11 minus one, which means it would take 10 cycles to completely degrade this particular fatty acid. So that would mean the answer would have to be option a 10 cycles.
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Problem
Problem
How many total FADH2, NADH, and acetyl CoA molecules will be produced when stearic acid undergoes β‑oxidation?
A
10 FADH2, 10 NADH, and 9 acetyl CoA
B
9 FADH2, 9 NADH, and 9 acetyl CoA
C
8 FADH2, 8 NADH, and 8 acetyl CoA
D
8 FADH2, 8 NADH, and 9 acetyl CoA
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Problem
Problem
Tripalmitin is a TAG formed by the esterification of glycerol with three palmitic acid molecules. How many acetyl CoA molecules will be produced by the complete oxidation of tripalmitin? (Hint: consider glycerol metabolism too).
A
22
B
24
C
25
D
26
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