In addition to Tox. 3, the researcher also discovers a related compound, which they creatively name Tox4. Tox4 causes lower than normal concentrations of H+ ions in the intermembrane space of the mitochondria. Which of these is NOT a likely mechanism of Tox4 given this information? A. Tox4 acts as the final electron acceptor in the ETC
B. Tox4 prevents cxygen from entering the mitochondria
C. Tox4 prevents the donation of electrons to the ETC by NADH
D. Tox4 causes H+ ions to freely diffuse across the inner mitochondrial membrane

The correct answer is option A. "Tox4 acts as the final electron acceptor in the ETC".

Explanation:

ATP synthase is an enzyme that catalyze the production of ATP in mitochondria. This enzyme acts by the presence of a proton gradient created in the intermembrane space during the electron transport chain (ETC) that is created in the mitochondria. If Tox4 causes lower than normal concentrations of protons in the intermembrane space, Tox4 is a compound that prevents the creation of the concentration gradient and prevents ATP synthase action. Therefore, Tox4 likely does not act by serving as the final electron acceptor in the ETC because this would promote the creation of the concentration gradient, which would be the opposite of Tox4 activity.

c. heat from the poles back down towards the equator.