8.4 Multiple Choice Flashcards
How can one increase the rate of a chemical reaction?
Add a catalyst
Sucrose is a disaccharide, composed of the monosaccharides glucose and fructose. The hydrolysis of sucrose by the enzyme sucrase results in
Breaking the bond between glucose and fructose and forming new bonds from the atoms of water
Reactions capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reactions
Activation energy
A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because
The activation energy barrier for this reaction cannot be surmounted
Which of the following statements regarding enzymes is true?
Enzymes increase the rate of a reaction
During a laboratory experiment, you discover that an enzyme-catalyze had a ?G of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the ?G for the new reaction?
-20 kcal/mol
The active site of an enzyme is the region that
Is involved in the catalytic reaction of the enzyme
According to the induced fit hypothesis of enzyme catalysis, which of the following is correct?
The binding of the substrate changes the shape of the enzymes active site
Which curve represents the behavior of an enzyme taken from a bacterium that lives in hot springs at temperatures of 70 or higher?
Curve 3
Which curve was most likely generated from analysis of an enzyme from a human stomach where conditions are strongly acid?
Curve 4
Which curve was most likely generated from an enzyme that requires a cofactor?
It is not possible to determine
Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?
Competitive inhibition
Which of the following is true of enzymes?
Enzymes increase the rate of chemical reaction by lowering activation energy barriers
Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as a
Cofactor necessary for enzyme activity
Based on this information, which of the following is correct?
Succinate is the substrate, and fumarate is the product
What is the purpose of using malonic acid in this experiment?
It is a competitive inhibitor
Which of the following terms best describes the reaction?
Exergonic
Which of the following represents the ?G of the reaction?
D
Which of the following would be the same in an enzyme-catalyzed or noncatalyzed reaction?
D
Which of the following best describes the reaction?
Negative ?G, spontaneous
Which of the following represents the difference between the free-energy content of the reaction and the free energy content of the products?
D
Which of the following represents the activation energy required for the enzyme catalyzed reaction?
B
Which of the following represents the activation energy required for a noncatalyzed reaction?
C
Which best describes the reaction?
The amount of free energy released as a result of the catalyzed reaction is indicated by ādā
Assume that the reaction has a ?G of -5.6 kcal/mol. Which of the following would be true?
The reaction would result in an increase in entropy and a decrease in the total energy content of the system
In order to attach a particular amino acid to the tRNA molecule that will transport it, an enzyme, an aminoacyl-tRNA synthetase, is required, along with ATP. Initially, the enzyme has an active site for ATP and another for the amino acid, but it is not able to attach the tRNA. What must occur in order for the final attachment to occur?
The binding of the first two molecules must cause a 3D change that opens another active site on the enzyme
Competitive inhibitors block the entry of substrate into the active site of an enzyme. On which of the following properties of an active site does this primarily depend?
The ability of an enzyme to form a template for holding and joining molecules
Which of the following is likely to lead to an increase in the concentration of ATP in a cell?
An increase in a cells catabolic activity
When you have a severe fever, what may be a grave consequence if this is not controlled?
Change in the folding of enzymes
How does a non competitive inhibitor decrease the rate of an enzyme reaction?
By changing the shape of a reactant
Which of the following statements describes enzyme cooperativity?
A substrate molecule bound to an active site affects the active site of several subunits
