A new antibiotic has been developed that inhibits the activity of an enzyme by competitive inhibition. What effect will this have on the activation energy of the enzyme-catalyzed reaction?

Question

A.  The activation energy required for the reaction in the presence of the antibiotic would be greater than the activation energy required in the absence of the antibiotic 
B.  The activation energy required for the reaction in the presence of the antibiotic would be less than the activation energy required in the absence of the antibiotic
C.  The activation energy required for the reaction in the presence of the antibiotic will be the same as the activation energy required in the absence of the antibiotic

Clarify Question
  What is the key concept addressed by the question?
What type of thinking is required?

  Gather Content
What do you already know about enzymes and activation energy? What factors influence activation energy? What other information is related to the question?

  Choose Answer
  Do you have all necessary information to analyze how the antibiotic might influence activation energy?

  Reflect on Process
  Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

C.  The activation energy required for the reaction in the presence of the antibiotic will be the same as the activation energy required in the absence of the antibiotic

Clarify Question
  What is the key concept addressed by the question?
        · The question asks you ascertain how an antibiotic that competitively inhibits an enzyme will affect the enzyme’s activation energy.
What type of thinking is required?
        · You are being asked to break down, or analyze, how a competitive inhibitor antibiotic will influence an enzyme’s activation energy.

  Gather Content
What do you already know about enzymes and activation energy? What factors influence activation energy? What other information is related to the question?
        · Remember that the activity of an enzyme is directly related to its structure and function. Recall that there are several structural elements of an enzyme that affect its function; these include the active site, which can be regulated by competitive inhibitors.
        · The question indicates that the antibiotic acts as a competitive inhibitor of the enzyme. Considering the structure and function of enyzmes and how competitive inhibitors work, how might the activation energy of the reaction be affected?

  Choose Answer
  Do you have all necessary information to analyze how the antibiotic might influence activation energy?
        · Recall that competitive inhibitors bind to the active site of the enzyme, which precludes the substrate binding to the same location. Thus, it will take more substrate to out-compete the competitive inhibitor, but with enough substrate this can be done and the enzyme will achieve the same maximum rate eventually, with or without the competitive inhibitor.
        · Regardless of how fast the enzyme can process the reaction (meaning with or without the competitive inhibitor), the actual energy costs associated with the reaction do not change. As a result, the competitive inhibitor antibiotic should have no effect on the activation energy required for the enzyme-catalyzed reaction.  

  Reflect on Process
  Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        · This question asked you to analyze the effect of a competitive inhibitor antibiotic on the activation energy for an enzyme-catalyzed reaction.
        · If you got the answer correct, good job! If you got an incorrect answer, did you remember that competitive inhibitors bind to the active site? Did you recall how competitive inhibitors affect overall reaction rate as substrate concentration changes? Were you able to determine that activation energy, the actual cost of the reaction, doesn’t change regardless of the presence or absence of a competitive inhibitor?