MCAT Question of the Day
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    Q:

    		 ATP can be generated by oxidative phosphorylation in the mitochondria via the electron transport chain, which comprises of a series of hydrogen pumps, electron carriers and ATP synthase. An electrochemical H+ gradient is produced across the inner mitochondrial membrane when H+ is pumped (driven by redox reactions within the proton pump complexes) from the matrix into the intermembrane space. The return of H+ into the matrix through ATP synthase drives the synthesis of ATP. Oligomycin is a macrolide (type of antibiotic) that inhibits the proton channel (F0 subunit) of ATP synthase. What can we expect to happen to the H+ electrochemical gradient with the introduction of oligomyciin?
    		 

    A

    		 The buildup of H+ in the intermembrane space would eventually overcome oligomycin and ATP would continue to be generated.

    B

    		 H+ would begin to flow from the intermembrane space into the matrix back through the proton pump complexes of the ETC.

    C

    		 The H+ gradient would be unaffected.

    D

    		 H+ would stop being pumped from the matrix into the intermembrane space.



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