In the reaction catalyzed by aconitase, the conversion of citrate to isocitrate is inhibited by fluoroacetate. Fluoroacetate is used as a pesticide. Why is this an effective pesticide?

Question

A.  It inhibits glycolysis
B.  It inhibits pyruvate oxidation
C.  It inhibits the Krebs cycle
D.  It inhibits the electron transport chain
E.  It inhibits ATP synthase

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 cellular respiration and when citrate is converted to isocitrate? What other information is related to the question?

  Choose Answer
  Do you have all necessary information to determine why fluoroacetate is an effective pesticide?

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.  It inhibits the Krebs cycle

Clarify Question
What is the key concept addressed by the question?
        · The question asks you to determine why fluoroacetate is an effective pesticide.
What type of thinking is required?
        · You are being asked to take what you know about citrate to isocitrate conversion, and apply your knowledge to determine why fluoroacetate is an effective pesticide.

  Gather Content
  What do you already know about cellular respiration and when citrate is converted to isocitrate? What other information is related to the question?
        ·Recall that cellular respiration involves glycolysis, pyruvate oxidation, the Krebs cycle, and the electron transport chain. During which of these stages is citrate converted to isocitrate by the aconitase enzyme, and which process would be inhibited by the fluoroacetate pesticide?

  Choose Answer
  Do you have all necessary information to determine why fluoroacetate is an effective pesticide?
        · Fluoroacetate prevents conversion of citrate to isocitrate, chemical reactions that only occur during the Krebs cycle. Citrate is not involved in glycolysis, pyruvate oxidation, or the electron transport chain, which would also preclude anything having to do with ATP synthase. Essentially, fluoroacetate would prevent aerobic respiration in organisms treated with this chemical.

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?
        · Answering this question correctly depended on your ability to apply what you know about the different stages of cellular respiration to identify which stage involves citrate to isocitrate conversion and use that to determine why fluoroacetate would be an effective pesticide..
        · If you got the correct answer, good thinking! If you got an incorrect answer, were you able to recall the different stages of cellular respiration? Were you able to identify which stage involves conversion of citrate to isocitrate? Were you able to infer that inhibition of this reaction would prevent the Krebs cycle from functioning?