One of the consequences of ethanol addiction is fattyliver disease, an illness in which liver cells accumulatetriacylglycerols, the esters derived from glycerol and fattyacids. Ethanol is oxidized in the cytoplasm of liver cells byalcohol dehydrogenase and aldehyde dehydrogenase to yieldacetate and 2 NADH. Acetate is then transported into themitochondrion, where it is converted to acetyl-CoA andmetabolized by the citric acid cycle. When alcohol is consumed in excessive quantities, the resulting high levels ofNADH cause metabolic abnormalities, one of which is highlevels of fatty acid synthesis. Fatty acid synthesis, also acytoplasmic process, uses acetyl-CoA as a substrate andNADPH as a reducing agent. Determine how a high level ofcytoplasmic NADH provides a source of NADPH for fattyacid synthesis.

One of the consequences of ethanol addiction is fattyliver disease, an illness in which liver cells accumulatetriacylglycerols, the esters derived from glycerol and fattyacids. Ethanol is oxidized in the cytoplasm of liver cells byalcohol dehydrogenase and aldehyde dehydrogenase to yieldacetate and 2 NADH. Acetate is then transported into themitochondrion, where it is converted to acetyl-CoA andmetabolized by the citric acid cycle. When alcohol is consumed in excessive quantities, the resulting high levels ofNADH cause metabolic abnormalities, one of which is highlevels of fatty acid synthesis. Fatty acid synthesis, also acytoplasmic process, uses acetyl-CoA as a substrate andNADPH as a reducing agent. Determine how a high level ofcytoplasmic NADH provides a source of NADPH for fattyacid synthesis.

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter19: The Tricarboxylic Acid Cycle

Section: Chapter Questions

Problem 22P: Study Figure 19.18 and decide which of the following statements is false. Pyruvate dehydrogenase is...

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One consequence of ethanol addiction is fatty liver disease, an illness in which liver cells accumulate large amounts of triacylglycerols, the esters derived from glycerol and fatty acids. Ethanol is oxidized in the cytoplasm of liver cells by alcohol dehydrogenase and aldehyde dehydrogenase to yield acetate and 2 NADH. Acetate is then transported into the mitochondrion, where it is converted to acetyl-CoA and metabolized in the citric acid cycle. When alcohol is consumed in excessive quantities, the resulting high levels of NADH cause metabolic abnormalities, one of which is high levels of fatty acid synthesis. Fatty acid synthesis, also a cytoplasmic process, uses acetyl-CoA as a substrate and NADPH as a reducing agent. Speculate about how a high level of cytoplasmic NADH provides a source of NADPH for fatty acid synthesis.
Which of the following citric acid cycle enzymes catalyzes substrate-level phosphorylation? A) isocitrate dehydrogenase B) α-ketoglutarate dehydrogenase C) succinyl CoA synthetase D) succinate dehydrogenase E) malate dehydrogenase
Which of the following is NOT a component of the pyruvate dehydrogenase complex? a. dihydrolipoyl dehydrogenase b. dihydrolipoyl transacetylase c. pyruvate dehydrogenase d. dihydrolipoyl catalase
During Krebs cycle, the conversion of isocitrate to alpha-keto glutarate involves all of the following reactions/mechanisms except Reduction of isocitrate Reduction of NAD+ Decarboxylation of isocitrate Oxidation of isocitrate
Which of the following statements are FALSE? a A compound is an inhibitor of Glyceraldehyde 3-phosphate Dehydrogenase. If this compound were added to liver cells where D-Glucose was the only substrate one should observe an accumulation of intermediates from Glucose 6-phosphate to Glyceraldehyde 3-phosphate and a depletion of those from 1-3-Bisphosphoglyceric Acid to Pyruvate. b If the substrate for liver cells (above problem) were L-Lactate there should be no effect on the concentrations of glycolytic intermediates with the exception being a potential increase in the concentration of Pyruvate. c When Glucose is converted to lactate there is no overall change in the oxidation state because Glyceraldehyde 3-phosphate Dehydrogenase oxidizes Glyceraldehyde 3-Phosphate to 1-3-Bisphosphoglyceric Acid but Lactate Dehydrogenase reduces Lactic Acid to Pyruvate. d If all the glycolytic enzymes were added to a mixture of ATP + ADP + NAD+ and Glucose the product…
The conversion of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate is the only oxidative reaction of glycolysis. True or false?
Select the following enzymes that utilize a mechanism where ATP serves as the phosphate donor. Select ALL that apply: a) glyceraldehyde 3 phosphate dehydrogenase b) hexokinase c) aldolase class 1 d) PFK e) phosphoglucoisomerase
Which of the following is most likely to cause accumulation of acetyl CoA? Group of answer choices There is not enough oxaloacetate present to run the citric acid cycle Increase activity of pyruvate dehydrogenase kinase Increased fatty acid synthesis Increased citrate synthase activity When fluoroacetate (an analog of acetate) is added to the mitochondria, it causes build up of fluorocitrate. Which of the following is most likely to be true? Group of answer choices Fluoroacetate cannot be converted to fluoroacetyl CoA Fluoroacetyl CoA cannot be combined with oxaloacetate to enter the citric acid cycle Addition of fluoroacetate will cause an increase in isocitrate Aconitase cannot use fluorocitrate as a substrate
Which of the following is true about comparing the α-ketoglutarate dehydrogenase complex and the pyruvate dehydrogenase complex? Group of answer choices They catalyze reactions that produce the exact same set of products They are both dehydrogenase complexes, but have very different structures They both catalyze reactions that oxidize NADH to NAD+ They both use the same E3 enzyme component Which of the following best describes stage 2 of the citric acid cycle? Group of answer choices ATP production by the electron transport chain production of acetyl CoA regeneration of oxaloacetate release of 2 carbons as carbon dioxide
3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA reductase) is a very long name for the enzyme that is involved in the production of cholesterol in the human liver. The enzyme catalyzes a reaction in which electrons are exchanged between reactants to form products. This an example of which of the following chemical reactions that are involved in maintaining homeostasis? HMG-CoA reductase catalyzes a catabolic reaction because electrons are exchanged between the reactants to form products. HMG-CoA reductase catalyzes a specific type of exchange reaction called an oxidation-reduction reaction in which electrons are exchanged between reactants to form products. HMG-CoA reductase catalyzes an anabolic reaction because electrons are exchanged between the reactants to form products. HMG-CoA reductase catalyzes a specific type of oxidation-reduction reaction called an exchange reaction in which atoms are exchanged between reactants to form products. Like most enzymes, HMG-CoA reductase…
The synthesis of 2,3-BPG from the glycolytic intermediate 1,3-BPG (glycerate-1,3-bisphosphate) is catalyzed by the enzyme bisphosphoglycerate mutase, one of many iron-requiring enzymes. What effect on oxygen delivery to the body’s tissues would be expected in the event of an irondeficient diet?
The glycerol derived from lipolysis of triacylglycerols is converted into glyceraldehyde 3-phosphate, which then enters into step 6 of the glycolysis pathway. What further transformations are necessary to convert glyceraldehyde 3-phosphate into pyruvate?