Which of the following events could directly increase the pH of the mitochondrial matrix?A.Permeabilization of the inner mitochondrial membraneB.Increased electron transport chain activityC.Increased ATP synthase activityD.Inhibition of the citric acid cycle
Question
Which of the following events could directly increase the pH of the mitochondrial matrix?A.Permeabilization of the inner mitochondrial membraneB.Increased electron transport chain activityC.Increased ATP synthase activityD.Inhibition of the citric acid cycle
Solution
The pH of a solution is a measure of its acidity or alkalinity. In the context of the mitochondrial matrix, an increase in pH would mean a decrease in acidity, or in other words, a decrease in the concentration of hydrogen ions (H+).
A. Permeabilization of the inner mitochondrial membrane: This would allow for the free flow of ions and molecules across the membrane, disrupting the proton gradient. This could potentially decrease the pH (increase acidity) if protons flow into the matrix, but it's not guaranteed to increase pH.
B. Increased electron transport chain activity: The electron transport chain (ETC) is responsible for pumping H+ ions from the matrix into the intermembrane space, creating a proton gradient. If the ETC activity increases, more H+ ions would be pumped out of the matrix, which would decrease the concentration of H+ ions in the matrix, thus increasing the pH.
C. Increased ATP synthase activity: ATP synthase works by allowing H+ ions to flow down their gradient from the intermembrane space back into the matrix, which is used to synthesize ATP from ADP. If ATP synthase activity increases, more H+ ions would flow into the matrix, which would increase the concentration of H+ ions in the matrix, thus decreasing the pH.
D. Inhibition of the citric acid cycle: The citric acid cycle produces NADH and FADH2, which donate electrons to the ETC. If the citric acid cycle is inhibited, less NADH and FADH2 would be produced, which would decrease the activity of the ETC. This would result in less H+ ions being pumped out of the matrix, which could potentially increase the concentration of H+ ions in the matrix, thus decreasing the pH.
Therefore, the event that could directly increase the pH of the mitochondrial matrix is B. Increased electron transport chain activity.
Similar Questions
A molecule enters a cell and creates pores in the inner mitochondrial membrane. How will ATP generation as a result of oxidative phosphorylation be affected? A.Increased, because the cell membrane is still complete and proton movement is increased.B.Increased, because ATP is required for cell function and this cell’s mitochondria will need to work harder.C.Decreased, because there is no available oxygen.D.Decreased, because the proton gradient will be dissipated.
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