(b) Fluoroacetate, prepared commercially for rodent control, is also produced by a South African plant.After entering a cell, fluoroacetate is converted to fluoroacetyl-CoA in a reaction catalyzed by the en-zyme acetate thiokinase:F-CH2COO + CoA-SH + ATPF-CH2CO-SCOA + AMP +PPThe toxic effect of fluoroacetate was studied in an experiment using intact isolated rat heart. After theheart was perfused with 0.22 mM fluoroacetate, the measured rate of glucose uptake and glycolysisdecreased, and glucose 6-phosphate and fructose 6-phosphate accumulated. Examination of the citricacid cycle intermediates revealed that their concentrations were below normal, except for citrate, witha concentration 10-fold higher than normal.(b1)the other cycle intermediates to be depleted? Explain. Why does it block the citric acid cycle?Where did the block in the citric acid cycle occur? What caused citrate to accumulate and(b2)structure of the end product of fluoroacetate metabolism?Fluoroacetyl-CoA is enzymatically transformed in the citric acid cycle. Name and draw the(ьз)How might the inhibition be overcome? Explain.

p) Fluoroacetate, prepared commercially for rodent control, is also produced by a South African plant. fter entering a cell, fluoroacetate is converted to fluoroacetyl-CoA in a reaction catalyzed by the en- yme acetate thiokinase: -CH2COO¯ + CoA-SH + ATP F-CH2CO-SCOA + AMP + PPj he toxic effect of fluoroacetate was studied in an experiment using intact isolated rat heart. After the eart was perfused with 0.22 mM fluoroacetate, the measured rate of glucose uptake and glycolysis ecreased, and glucose 6-phosphate and fructose 6-phosphate accumulated. Examination of the citric cid cycle intermediates revealed that their concentrations were below normal, except for citrate, with concentration 10-fold higher than normal. 1) e other cycle intermediates to be depleted? Explain. Why does it block the citric acid cycle? Where did the block in the citric acid cycle occur? What caused citrate to accumulate and

p) Fluoroacetate, prepared commercially for rodent control, is also produced by a South African plant. fter entering a cell, fluoroacetate is converted to fluoroacetyl-CoA in a reaction catalyzed by the en- yme acetate thiokinase: -CH2COO¯ + CoA-SH + ATP F-CH2CO-SCOA + AMP + PPj he toxic effect of fluoroacetate was studied in an experiment using intact isolated rat heart. After the eart was perfused with 0.22 mM fluoroacetate, the measured rate of glucose uptake and glycolysis ecreased, and glucose 6-phosphate and fructose 6-phosphate accumulated. Examination of the citric cid cycle intermediates revealed that their concentrations were below normal, except for citrate, with concentration 10-fold higher than normal. 1) e other cycle intermediates to be depleted? Explain. Why does it block the citric acid cycle? Where did the block in the citric acid cycle occur? What caused citrate to accumulate and

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter18: Glycolysis

Section: Chapter Questions

Problem 20P: Understanding the Mechanism of Hemolytic Anemia Genetic defects in glycolytic enzymes can have...

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Study Figure 19.18 and decide which of the following statements is false. Pyruvate dehydrogenase is inhibited byÂ· NIADH. Pyruvate dehydrogenase is inhibited by AÎ¤Î¡. Citrate synthase is inhibited by NADH. Succinyl-CoA activates citrate synthase. Acetyl-CoA activates pyruvate carboxylase.
succinyl-COA synthetase will do which of the following: Select one: a. Fumarate is combined with water to become Malate b. alpha-ketoglutarate is oxidized and decarboxylated to produce Succinyl-CoA, Carbon dioxide and NADH c. Succinate is oxidized to become fumarate forming FADH2 d. Citrate is rearranged to become Isocitrate e. Malate is oxidized to become oxaloacetate forming NADH f. Pyruvate is decarboxylated to become acetyl-CoA producing NADH and Carbon dioxide g. Succinyl-CoA becomes Succinate and forms one ATP molecule and Coenzyme A-SH h. Oxaloacetate combines with the acetyl from acetyl-CoA to produce Citric acid(citrate) i. Isocitrate and then decarboxylated and oxidized to produce alpha-ketoglutarate, Carbon dioxide and NADH
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 statements is falseconcerning acetyl CoA carboxylase (ACC)? ACC is more active when protomers condense to form polymers Palmitoyl CoA serves as a feedback inhibitor The source of carbons for ACC comes from the carbon skeletons of malate that is exported from the matrix of the mitochondria in the form of malate Binding of glucagon triggers cAMP production, which leads to inhibition of ACC
When one acetyl CoA is processed through the citric acid cycle, how many times does each of the following events occur? a. A FAD molecule is a reactant. b. A CoA-SH molecule is produced. c. A dehydrogenase enzyme is needed for the reaction to occur. d. A C5 molecule is produced.
Name one reaction of glycolysis, one anaplerotic reaction, and one reaction of TCA cycle that acetyl-COA allostericqally regulates ( and declare whether it is an activator or inhibitor.)
When transaminated, the three branched-chain amino acids (valine, leucine, and isoleucine) form compounds that have the characteristic odor of maple syrup. An enzyme known as branched-chain a-keto acid dehydrogenase converts these compounds into CoA esters. People who do not have this enzyme have the genetic disease known as maple syrup urine disease, so called because their urine smells like maple syrup. a. Draw the compounds that smell like maple syrup.b. Draw the CoA esters.c. Branched-chain a-keto acid dehydrogenase has five coenzymes. Identify them.d. Suggest a way to treat maple syrup urine disease.
A fatty acid (a long straight-chain carboxylic acid with an even number of carbons) is metabolized to acetylCoA, which can then enter the citric acid cycle to be further metabolized. A fatty acid with an odd number of carbons is metabolized to acetyl-CoA and one equivalent of propionyl-CoA. Propionyl-CoA cannot enter the citric acid cycle. Two coenzyme-requiring enzymes are needed to convert it to succinyl-CoA, a compound that can enter the citric acid cycle. Write the two enzyme-catalyzed reactions and include the names of the required coenzymes.
Complete the following paragraph describing the fate of the second 14CO-acetyl-CoA molecule incorporated into the glyoxylate cycle. The glyoxylate produced in the isocitrate reaction combines with a (A.) 2nd molecule of oxoaloacetate, B.) 2nd molecule of succinate, C.)2nd molecule of acetyl coa) in the malate synthase reaction. Malate is (A.Chiral, B.diasteromeoic C.)Achiral) ; therefore, the oxaloacetate produced from glyoxylate will be labeled at (A.Either of carboxylate carbon B. specifically at methylene carbon C. Specifically at carbonyl carbon D. Specifically at carboxylate carbon bonded to methylene).
The malaria parasite Plasmodium falciparum does not carry out oxidative phosphorylation and therefore does not use the citric acid cycle to generate reduced cofactors. Instead, the parasite converts amino acid–derived α ketoglutarate to succinate. Write an equation for the α-ketoglutarate → succinate conversion that follows (a) the oxidative (clockwise) path of the citric acid cycle or (b) the reductive (counterclockwise) path of the cycle.
alpha-ketoglutarate dehydrogenase will do which of the following: Select one: a. Pyruvate is decarboxylated to become acetyl-CoA producing NADH and Carbon dioxide b. Succinate is oxidized to become fumarate forming FADH2 c. Succinyl-CoA becomes Succinate and forms one ATP molecule and Coenzyme A-SH d. Oxaloacetate combines with the acetyl from acetyl-CoA to produce Citric acid(citrate) e. Malate is oxidized to become oxaloacetate forming NADH f. Isocitrate and then decarboxylated and oxidized to produce alpha-ketoglutarate, Carbon dioxide and NADH g. Citrate is rearranged to become Isocitrate h. Fumarate is combined with water to become Malate i. alpha-ketoglutarate is oxidized and decarboxylated to produce Succinyl-CoA, Carbon dioxide and NADH
Two carbon atoms are fed into the citric acid cycle as acetyl-CoA. In what form are two carbon atoms removed from the cycle?