Summary of Lipid Metabolism - Video Tutorials & Practice Problems
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1
concept
Summary of Lipid Metabolism Concept 1
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Video transcript
Here, we can say that the metabolic pathways of lipid and carbohydrate metabolism are both interconnected with one another. We're gonna say these different metabolic pathways can be taken to generate acetyl coa acetic coa itself can then do various things such as a TP production, uh formation of ketone bodies or even the regeneration of fatty acids. Now, if we take a look here, we have our illustration that basically breaks this down into different places. We have the exterior of the cell, we have our cell membrane, we have our cytosol and we have our mitochondrial membranes and the mitochondrial matrix. You might also notice different colors of arrows. If we take a look here, the black arrows deal with our cat bolic pathways where our lipids and carbohydrates are descending downward from the exterior the cell towards the mitochondrial matrix to their even formation of acetyl coa and then eventually acetyl coa goes through the citric acid cycle, then etc and oxidative phosphorylation to create a TP. So here, that's the end game here. If we wanna have the generation of a lot of energy, we also have our green arrows which are the anabolic pathways. We're gonna say here, if we look at our anabolic pathways, we can have acetyl coa which does ketogenesis in the formation of ketone bodies, which themselves can be shuttled out of the matrix back into the cytosol. We can have our green arrows where a PSEO coe regenerates is regenerated or actually shuttled out of the matrix to recreate fatty acids to fatty acid synthesis or the formation of cholesterol. We also have this green arrow or pyruvate and basically go backwards to recreate glucose by gluconeogenesis. Then finally, we have these purple arrows. These purple arrows are our transport arrows or we're talking about transporting across a membrane. Now, if we take a look, we have our lipids that are on the exterior of the cell. When they cross a cell membrane, they're undergoing digestion, lipids are broken down into their fatty acids and glycerol components carbohydrates into glucose. Now, these fatty acids can be shuttled across the mitochondrial matrix of mitochondrial membrane into matrix. This fatty acid can then undergo beta oxidation to create acetyl coa again, this acetylate could form ketone bodies if our low, if we have low carbohydrates, or it can go onwards towards the TC A and eventually the formation of A TP. And then we can say here, acetyl coa if there's just an excess of it, it can be shuttled out of the matrix back into the cytosol so that we can have the formation of fatty acids. Now, here we've talked about some of these processes. Before this again, is a good overview of the pathway that lipids and carbohydrates can take in relation to uh metabolic pathways. We can say next that Glycerol, which is the other component of our lipid. It can basically go into gluconeogenesis and help uh in the creation of glucose from pyruvate. Here. Also being involved, we could also say that G glycerol does have its place as well in glycolysis where we have glucose changing into pyruvate. Now, this glucose happens when we have the digestion of carbohydrates as they cross the cell membrane. Once we have our glucose, they undergo glu uh glycolysis to make pyruvate. Pyruvate can be transported across the mitochondrial membranes into the matrix that pyruvate can then be changed into acetyl coa. And then again, acetylate its fates are, if there's low carbohydrates, it becomes keto bodies. If this excess of acetyl coa can be shuttled out of the matrix or we can have acetylate going through the necessary steps, getting to oxidative phosphorylation to make more a TP. So this is a lot of different processes, but you can see where we have connections between lipids and carbohydrates. Now, here we're going to say, Acito Koe serves as a central metabolite within food metabolism. We can see that although lipids and carbohydrates are different, they can both wind up at Acito Koe. And we're gonna say here, Acito Koe, it can serve as an end product for glucose for glycerol and fatty acid metabolic pathways here. And then we can say that it can serve as the starting material for the production of ketone bodies. We can seek lipids as well as cholesterols. So just remember, we have our catic pathways where we have our lipids and carbohydrates trying to get to acetyl coa. We also have our anabolic pathways where PSEO can basically become different things such as ketone bodies moving out of the matrix to create more fatty acids and cholesterol, we can have py going backwards through Glucon genesis to make uh glucose, right. So just keep this in mind while we're talking about the overall idea of the metabolic pathways of lipids and carbohydrates.
2
example
Summary of Lipid Metabolism Example 1
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1m
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Video transcript
Here in this example question, it says acetyl coa cannot be converted from which of the following molecules, right. So acetyl coa serves as a central metabolite when we talk about lipid and carbohydrate metabolism. Now, here we can say that acetyl coa can be formed from a fatty acid if we do beta oxidation. If we take a look at our options, here, we have stere which is the salt of a fatty acid because it is a fatty acid in essence, it could be converted through beta oxidation to form acetylate. Next, we have pyruvate, pyruvate can be created from glycolysis when we break down glucose to make on its trip to acetyl coa. So remember we have glucose goes through glycolysis to make pyruvate pyruvate can be shoved across a mitochondrial membrane to the matrix where then is changed into Cylco, then we have maltose and we have N A DH maltose represents a disaccharide. We could hydrolyze this, splitting it up into two glucose molecules. Again, those glucose molecules could undergo glycolysis to pyruvate pyruvate to aceto coa. So here the odd one out would be an A DH, we can't directly convert here N A DH into our C A. We didn't see that as a possible path, metabolic path in terms of changing it into acetyl coa remember acetyl coa goes into the citric acid cycle. N A DH is one of the things that can be produced from that cycle. So here the answer would be option C.
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Problem
Problem
Regarding lipid metabolism, match the following terms with B-oxidation (A), Ketogenesis (B) or neither (C).
I. ______ Acetoacetyl CoA
II. ______ Fructose
III. ______ The carnitine shuttle
IV. ______ Acyl CoA dehydrogenase
A
I. (A), II. (C), III (A), IV. (B)
B
I. (A), II. (C), III (A), IV. (A)
C
I. (B), II. (C), III (A), IV. (A)
D
I. (A), II. (B), III (A), IV. (C)
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Problem
Problem
Determine which of the following processes occurs in the Mitochondrial Matrix (MM), Cytosol (C) or Exterior of the Cell (X).
I. ______ Glycerol kinase converts glycerol to glycerol-3-phosphate.
II. ______ Hydrolysis of glycogen.
III. ______ FADH2 is oxidized to FAD.
IV. ______ The enzyme aconitase isomerizes citrate to isocitrate.
A
I. (C), II. (C), III. (MM), IV. (X)
B
I. (C), II. (C), III. (MM), IV. (MM)
C
I. (C), II. (MM), III. (MM), IV. (MM)
D
I. (X), II. (C), III. (MM), IV. (MM)
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Problem
Problem
Which of the following statements is true?
A
Both FA synthesis and glycolysis occur in the matrix.
B
Oxidation of a secondary alcohol happens during Step 2 of glycerol metabolism.
C
Gluconeogenesis occurs within the mitochondrial membrane.
D
Ketogenesis begins with the decarboxylation reaction between 2 acetyl CoA molecules.
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