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Kaplan Qbank USMLE



Author4 Posts
  #1

Rotenone is used in several commercial rat poisons, and this substance inhibits the
functioning of Complex I of electron transport. This substance inhibits mitochondrial
electron transport and prevents the translocation of hydrogen ions:

(A) from the intermembrane space to the mitochondrial matrix

(B) from the cytosol to the intermembrane space

(C) from the mitochondrial matrix to the intermembrane space

(D) from the intermembrane space to the cytosol

(E) from the intermembrane space to the outer mitochondrial membrane

  #2

C.. right??


  #3

the answer is C: the complex 1, as all the complexes of the electron transport chain (1 2 3 4 5), are located inside the inner mitocondrial membrane, that stays beetween the mitochondrial matrix and the intermembrane space. when nadh in the mithocondrial matrix links to the complex 1, determining n electron flow through the respiratory chain and the passage of H+ from the matrix to the intermembrane sae. These H+ will return to the matrix passing through the complex V, also called atp synthase, determining the formation of atp!

  #4

very nicely explained ..thanx eytanraz....C.......................







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