Multiple Choice Questions

You have an enzymatic reaction proceeding at the optimum pH and optimum temperature. You add a competitive inhibitor to the reaction and notice that the reaction slows down.What can you do to speed the reaction up again?
  • The enzyme is inactive at this point. New enzyme must be added to regain enzyme activity
  • uncatalyzed reaction (lowest) < reaction catalyzed by enzyme A < reaction catalyzed by enzyme B (highest)
  • The active site can provide heat from the environment that raises the energy content of the substrate
  • Add more substrate; it will outcompete the inhibitor and increase the reaction rate
What name is given to the reactants in an enzymatically catalyzed reaction?
  • substrate
  • denatured
  • catalyst
  • active site
When the noncompetitive inhibitor is bonded to the enzyme, the shape of the ______ is distorted.
  • specific
  • catalyst
  • complex
  • enzyme
Enzymes are described as catalysts, which means that they __________.
  • They consume energy to build polymers from monomers
  • increase the rate of a reaction without being consumed by the reaction
  • Adenosine triphosphate (ATP) is the high-energy form of adenosine because it contains the most phosphate groups (three)
  • Enzymes increase the rate of a reaction by lowering the activation energy barrier
An enzyme is considered a ________ because it speeds up chemical reactions without being used up.
  • catalyst
  • substrate
  • complex
  • active site
A chemical reaction that has a positive ΔG is best described as
  • active site
  • endergonic
  • specific
  • substrate
Which of the following is true for anabolic pathways?
  • Enzymes increase the rate of a reaction by lowering the activation energy barrier
  • The reaction proceeds with a net release of free energy
  • The cycling between ATP and ADP + Pi provides an energy coupling between catabolic and anabolic pathways
  • They consume energy to build polymers from monomers
Which of the following statements about the role of ATP in cell metabolism is true?
  • The reaction proceeds with a net release of free energy
  • The entropy of the products is greater than the entropy of the reactants
  • The cycling between ATP and ADP + Pi provides an energy coupling between catabolic and anabolic pathways
  • The energy from the hydrolysis of ATP may be directly coupled to endergonic processes by the transfer of the phosphate group to another molecule
Which of the following statements regarding enzymes is true?
  • The reaction proceeds with a net release of free energy
  • Enzymes increase the rate of a reaction by lowering the activation energy barrier
  • They consume energy to build polymers from monomers
  • The cycling between ATP and ADP + Pi provides an energy coupling between catabolic and anabolic pathways
Which of the following statements about ATP (adenosine triphosphate) is correct?
  • Enzymes increase the rate of a reaction by lowering the activation energy barrier
  • They consume energy to build polymers from monomers
  • The cycling between ATP and ADP + Pi provides an energy coupling between catabolic and anabolic pathways
  • The energy from the hydrolysis of ATP may be directly coupled to endergonic processes by the transfer of the phosphate group to another molecule
Usually, a(n) ________ inhibitor forms a covalent bond with an amino acid side group within the active site, which prevents the substrate from entering the active site or prevents catalytic activity.
  • competitive
  • is unchanged
  • irreversible
  • active site
Select the correct statement about chemical energy, a term used by biologists to refer to potential energy available for release in a chemical reaction.
  • The entropy of the products is greater than the entropy of the reactants
  • Adenosine triphosphate (ATP) is the high-energy form of adenosine because it contains the most phosphate groups (three)
  • Light energy is converted to chemical energy during photosynthesis
  • The energy from the hydrolysis of ATP may be directly coupled to endergonic processes by the transfer of the phosphate group to another molecule
An enzyme is ______ when it loses its native conformation and its biological activity.
  • active site
  • substrate
  • catalyst
  • denatured
Select the highest energy form of adenosine from the following images
w9SnAmZWQGIjMEWqq5O-lQ_m.png
  • When substrate molecules bind to the active site of the enzyme, the enzyme undergoes a slight change in shape
  • Adenosine triphosphate (ATP) is the high-energy form of adenosine because it contains the most phosphate groups (three)
  • The active site can provide heat from the environment that raises the energy content of the substrate
  • The cycling between ATP and ADP + Pi provides an energy coupling between catabolic and anabolic pathways
The graph presents three activation energy profiles for a chemical reaction (the hydrolysis of sucrose): an uncatalyzed reaction, and the same reaction catalyzed by two different enzymes.Rank these by reaction rate, as measured by the rate of product formation per unit time, from lowest reaction rate to highest reaction rate. To rank items as equivalent, overlap them.
  • The cycling between ATP and ADP + Pi provides an energy coupling between catabolic and anabolic pathways
  • Add more substrate; it will outcompete the inhibitor and increase the reaction rate
  • uncatalyzed reaction (lowest) < reaction catalyzed by enzyme A < reaction catalyzed by enzyme B (highest)
  • The active site can provide heat from the environment that raises the energy content of the substrate
You have added an irreversible inhibitor to a sample of enzyme and substrate. At this point, the reaction has stopped completely.What can you do to regain the activity of the enzyme?
  • Light energy is converted to chemical energy during photosynthesis
  • The enzyme is inactive at this point. New enzyme must be added to regain enzyme activity
  • The entropy of the products is greater than the entropy of the reactants
  • The active site can provide heat from the environment that raises the energy content of the substrate
Which of the following statements is most likely to be true in the case of the feedback-regulated enzymatic pathway shown?
2dj8cDHeV3aIZKt8uMTQ0w_m.jpg
  • the terminal phosphate (γγ-phosphate)
  • The entropy of the products is greater than the entropy of the reactants
  • P4 binds E1 and deactivates it
  • They consume energy to build polymers from monomers
Which statement about the binding of enzymes and substrates is correct?
sIEQqwBztKiMZo632ZGdWQ_m.jpg
  • When substrate molecules bind to the active site of the enzyme, the enzyme undergoes a slight change in shape
  • Adenosine triphosphate (ATP) is the high-energy form of adenosine because it contains the most phosphate groups (three)
  • Enzymes increase the rate of a reaction by lowering the activation energy barrier
  • The energy from the hydrolysis of ATP may be directly coupled to endergonic processes by the transfer of the phosphate group to another molecule
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Multiple Choice Questions
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