M Prep | MCAT 2015 Question of the Day - Prep, Practice Questions, and More!

MCAT Question of the Day

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.

Oxidative Phosphorylation | Membrane Transport and Signalling |

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