Ketone Bodies - Video Tutorials & Practice Problems
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Ketone Bodies Concept 1
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Hey, everyone. So when we say ketone bodies, these are our three acetyl coa metabolites produced in the mitochondria of the liver. And we're gonna see that they are used as an energy source by the heart, skeletal muscles and brain. When glucose is not available, now you'll need to know what these three ketone bodies look like. And when we talk about them, we're gonna say two of them are ketones, hence the name ketone bodies. But then the last one has a alcohol group and is represented as a carbonic acid as well. So here, the first ketone body is our acetone. Here, we'd have this central carbon being our carbon carbon, meaning it's ac double bond o next, we have aceto acetate. So here we have a carbolic acid group that has lost its h positive. So it's in its conjugate base form. It is also a ketone and it's this carbon here. That is the carbon carbon. Then finally, the last one we have that is not a kone. It is a three hydroxybutyrate. Here we're gonna say hydrox, you remember means an oh group. We say that the carbon carbon here is carbon one. This is 23 and four. So we're gonna say that is carbon number three is where the oh will be. So this represents our three different types of ketone bodies. Again, you're gonna need to remember what they look like and the names that are attached to them.
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Ketone Bodies Concept 2
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Now we take a look at an overview of food metabolism. Remember we have stage one in stage one, we are going to digest our lipids which breaks it up into its fatty acids and glycerol components. Remember here, we're looking at the fatty acids, the fatty acid has to be activated. So we have to consume a TP. Remember there is a one time cost of two A TPS to do this doing this helps us to activate our fatty acid and change it into this fatty acid. A acyl coa all this occurs within the cytosol. We're gonna say here it then is going to pass the mitochondrial matrix where we have beta oxidation and we're gonna have the formation of acetyl coa. Now ketogenesis is just the synthesis of ketone bodies from acetyl coa. And we're gonna say this occurs during low carbohydrate diets, starvation or due to diabetes. So instead of continuing on to stages three and four of food metabolism, we're going to move downward this way towards ketogenesis, thus creating ketone bodies. So just remember, in order for ketone bodies to form, we need to utilize acetyl coa and this occurs when we have low carbohydrates available when we are in starvation or when we have diabetes.
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Ketone Bodies Concept 3
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Now, beta oxidation of a fatty acid produces excess amounts of acetyl coa that cannot be processed by the citric acid cycle. Now, here we're going to say that in low levels of carbohydrates, we're going to deplete a Xylo acetate. And we're gonna say, recall that gluconeogenesis creates and uses this oxy acetate here. If we take a overview of the citric acid cycle or creb cycle, we have oxy AA which is produced in the final stage. It can join with acetylate in the formation of citrate to begin another cycle of the creb cycle. Now, if our carbohydrates are low, then going through glycolysis, we'd have a low amount of pyruvic being formed. And because of this, this would interfere with the production of oiloy. Now, here we're gonna say we have ketosis, which we're gonna say is a condition where large amounts of ketone bodies are present in the blood and the urine. And we're gonna say here that two of the ketone bodies. Again, remember are carbolic acids in nature and cause ketoacidosis from the name acid. It acidifies acidifies our blood and it's gonna cause a decrease in the blood. Ph Now, here, this type of condition is mainly in diabetics. So it's not common unless you're diabetic. So just remember that when we're dealing with this low amount of carbohydrates, we're gonna have the proliferation or creation of all these ketone bodies that can be detrimental to the ph balance of our blood rating. This condition of ketoacidosis.
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Ketone Bodies Example 1
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Here it says which statement best describes the process of ketogenesis. Now, remember, ketogenesis itself is the synthesis of ketone bodies or masto coa. This typically happens when we're on a low carbohydrate diet are in starvation mode or if we are diabetic. Now, here we're gonna say ketone bodies are synthesized in the mitochondria of adipose cells here. That's not true. It's not in the mitochondria of adipose cells. It's in the mitochondria of the liver excess glucose leads to the formation of ketone bodies from pyruvate. Now, remember ketone bodies happen when we're dealing with a low carbohydrate diet. So we wouldn't have an excess of glucose. We'd have a deficiency of glucose. Ketone bodies are synthesized from oxy acetate, which is a metabolite that is converted from excess acetylate. All right. So here, there's a lot to be said here in terms of this ketone bodies are synthesized from acetyl coa itself, not oxalacetate. And we're gonna say here that oxy acetate can work in conjunction with acetyl coa to create citrate. So there's a lot wrong with this sentence. Ketogenesis occurs as a result of deficiency of glucose. That's true. It can cause high levels of aceto acetate in the blood. Now, aceto acetate represents one of the carbolic acid ketone bodies. Uh A lot of that would create a condition known as ketoacidosis, which can happen if we have too many ketone bodies within our blood and urine. So here, this statement is the most true out of all the statements given to us. The final answer is option D.
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Ketone Bodies Concept 4
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Here in this video, we're gonna talk about the first ketogenesis reaction, which is a condensation reaction within it. We have two acetyl coa molecules that condense forming a four carbon intermediate. Now here, this can be seen as the reverse of the last step of beta oxidation. If we take a look here at this reaction, we have two acetyl coa molecules and we're going to say that they're going to join together to create this aceto acetyl coa. Now, in order to do this, we're gonna have to have the loss of our co a file here or sh group actually. And we're gonna say here, the easiest way to think about what occurs is we'd have the loss of this sulfur and ka and a hydrogen from this metal group. So those are lost. What is left behind is what comes together to make my product. So we have left this metal group in this carbon, which is this portion here, we're gonna say that this ch three is no longer ach three, it's lost a hydrogen. So it's ach two now, which is because it's still connected to this carbonyl sulfur and Ka Carny sulfur and Kate, they are joined together by this bond. OK. So remember this is condensation, we have the loss of Kash in order to create this aceto acetyl coa as a product.
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Ketone Bodies Concept 5
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Now, our second reaction under ketogenesis is hydrolysis. This is gonna be the cleavage of an acetyl acetyl coa which forms our first ketone body here in relation to aceto aetate. So here we're creating aceto acetate. So here we have our acetyl coa we're gonna utilize water because this is a hydrolysis. We're gonna utilize water and that's gonna help us to lose this sulfur kate portion. And what we're gonna have is an oxygen being placed here. So we've just made a carboxylate an ion and help us make our aceto acetate, right. So, just remember in this first one, we're doing the cleavage of our acetyl a aceto acetyl coa that we made under the condensation reaction before this one, right. So, in order to make our first ketone body.
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Ketone Bodies Concept 6
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Now, in our continued discussion of the ketogenesis reactions, we now are at step three, but we have a reduction in decarboxylate. Now, here we have aceto acetate here in the center and we're gonna say that it is reduced to form our second ketone body which is three hydroxybutyrate. If we take a look here, we have aceto acetate. We're gonna use N A DH. It's going to become oxidized to create N ad positive because N A DH is oxidized. That means a CTO AA is reduced, it gets reduced into three hydroxybutyrate. Here, this would be carbon 123 and four on carbon three. We have a hydroxy. Again, remember that just means an oh, so we've reduced our ketone to a secondary alcohol to make three hydroxybutyrate. Also, we can say when in the bloodstream, some aceto aetate can also be decarboxylate in order to form acetone. So here we'd have decarboxylate, we have the loss of carbon dioxide, doing this would help us to form our acetone, which is yet another ketone body, right? So just remember this third step, we can look at it in terms of reduction, going from aceto acetate to three hydroxybutyrate or we can look at it as a decarboxylate where ceo acetate undergoes decarboxylate to create acetone.
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Ketone Bodies Example 2
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Here. This example question, it says the ketone body produced during hydrolysis reaction of ketogenesis is. So, first of all, remember, there are three ketone bodies. They are aceto acetate acetone and three hydroxybutyrate. Option C acetate isn't a ketone body. So it's out. The answer here would be option. A option. A aceto aetate is created through a hydrolysis reaction and it happens when we have a aceto acetyl coa undergoing a hydrolysis reaction to create aceto aetate. Now here acetone is created from aceto acetate by decarboxylate, not hydrolysis and three hydroxybutyrate is created through aceto acetate as well, but through a reduction. So again, the only answer here that's created through hydrolysis will be option A aceto A.
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Problem
Problem
Which reaction produces a ketone body with an alcohol functional group? Draw the ketone body.
A
condensation
B
hydrolysis
C
reduction
D
decarboxylation
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Problem
Problem
How is oxaloacetate related to ketone bodies formation?
A
High levels of acetyl CoA accumulate and increase the rate of citric acid cycle.
B
Oxaloacetate combines with acetyl CoA to form citrate; this leads to formation of ketone bodies.
C
Citric acid cycle is not dependent on oxaloacetate, and all acetyl CoA is free to be oxidized in the cycle.
D
Ketone bodies are formed when oxaloacetate levels are low.
E
Ketogenesis can speed up gluconeogenesis by producing more oxaloacetate.