Biochemistry : Biochemistry
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Example Questions
Example Question #1 : Lipid Catabolism
What enzyme performs the shown step in beta oxidation?
Acyl-CoA dehydrogenase
CoA dehydroxlase
Acetyl-CoA dehydrogenase
Acyl-CoA oxidase
Thiolase
Acyl-CoA dehydrogenase
This first step of beta oxidation is catalyzed by acyl-CoA dehydrogenase. One way to remember is that the enzyme is named for exactly what it does: remove a hydrogen (dehydrogenate) from acyl-CoA, which is the reactant. In order to be acetyl-CoA the R-group must specifically be a methyl group.
Example Question #2 : Lipid Catabolism
What enzyme performs the shown step in beta oxidation?
Acyl-CoA hydratase
Enoyl-CoA hydratase
Acyl-CoA dehydrogenase
Thiolase
Acyl-CoA oxidase
Enoyl-CoA hydratase
This second step of beta oxidation is catalyzed by enoyl-CoA hydratase. One way to remember is that the enzyme is named for exactly what it does: adding water (hydrate) across the double bond of enoyl-CoA, which is the reactant.
Example Question #3 : Lipid Catabolism
What enzyme catalyses the shown step in beta oxidation?
Acyl-CoA dehydrogenase
L-hydroxacyl-CoA dehydrogenase
Enoyl-CoA hydratase
L-hydroxacyl-CoA dehydrogenase
Acyl-CoA dehydroxylase
L-hydroxacyl-CoA dehydrogenase
This third step in beta oxidation is catalyzed by L-hydroxacyl-CoA dehydrogenase. One way to remember is that the enzyme is named for exactly what it does: remove a hydrogen (dehydrogenate) L-hydroxyacyl-CoA (the reactant).
Example Question #4 : Lipid Catabolism
What enzyme catalyses the below step in beta oxidation?
Acyl-CoA dehydrogenase
L-hydroxacyl-CoA dehydrogenase
Acetyl-CoA synthase
Thiolase
Enoyl-CoA hydratase
Thiolase
This fourth step in beta oxidation is catalyzed by thiolase. The reduced form of coenzyme-A is used as a cofactor to cleave the bond between the alpha and the beta carbon.
Example Question #751 : Biochemistry
Which cofactor is required in the conversion of fatty acyl-CoA to trans enoyl-CoA by acyl-CoA dehydrogenase?
Biotin
Water
Pyridoxal
Example Question #31 : Catabolic Pathways And Metabolism
What reaction in beta oxidation does enoyl-CoA hydratase catalyze?
The removal of water across the carbon-carbon double bond
The addition of water across the carbon-oxygen double bond
The addition of water across the carbon-carbon double bond
The formation of a carbon-carbon double bond by adding water
The removal of water across the carbon-oxygen double bond
The addition of water across the carbon-carbon double bond
Enoyl-CoA hydratase catalyzes the the addition of water across the carbon-carbon double bond.
Example Question #31 : Catabolic Pathways And Metabolism
Which reaction in beta oxidation does hydroxyacyl-CoA dehydrogenase catalyze?
Reduction of the beta hydroxyl group
Dehydration of the beta carbon
Dehydration of the carbonyl carbon
Oxidation the gamma carbon
Oxidation of the beta hydroxyl group
Oxidation of the beta hydroxyl group
Hydroxyacyl-CoA dehydrogenase oxidizes the beta hydroxyl group, forming a carbonyl.
Example Question #32 : Catabolic Pathways And Metabolism
What reaction in beta oxidation does thiolase catalyze?
Cleavage of the beta-ketoacyl-CoA
Cleavage of the sulfur-carbon bond
Cleavage of the alpha-ketoacyl-CoA
Cleavage of the sulfur-CoA bond
Cleavage of the beta carbonyl
Cleavage of the beta-ketoacyl-CoA
Thiolase catalyzes the cleavage of the beta-ketoacyl-CoA.
Example Question #33 : Catabolic Pathways And Metabolism
What are the two major products of the thiolase-catalyzed reaction?
Acetyl-CoA and a fatty acyl-CoA shortened by two carbons
Acyl-CoA and a fatty acyl-CoA shortened by one carbon
Acetyl-CoA and a fatty acyl-CoA shortened by one carbon
Thiol and a fatty acyl-CoA shortened by two carbons
Acyl-CoA and a fatty acyl-CoA shortened by two carbons
Acetyl-CoA and a fatty acyl-CoA shortened by two carbons
The two major products of the thiolase-catalyzed reaction are acetyl-CoA and a fatty acyl-CoA shortened by two carbons.
Example Question #11 : Lipid Catabolism Enzymes
The beta oxidation pathway can be described as __________.
cyclic
linear
inhibitor-regulated
anabolic
inhibitor-dependent
cyclic
The beta-oxidation pathway is cyclic. Two carbons are removed from a fatty acid chain each time it goes around the pathway. If the initial fatty acid chain has an even number of carbons then the final round of beta oxidation yields two copies of acetyl-CoA.
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