When hydrogen ions accumulate in the mitochondrial intermembrane space, what prevents them from moving back into the mitochondrial matrix without flowing through ATP synthase?
A)The hydrophilic environment of the mitochondrial matrix repels hydrogen ions.
B)The hydrophobic environment of the mitochondrial matrix repels hydrogen ions.
C)Hydrogen ions combine with oxygen gas to form water, which cannot cross the lipid bilayer of the mitochondrial membrane.
D)Hydrogen ions cannot cross the lipid bilayer of the mitochondrial membrane.
E)Entering the matrix would require the ions to move against their concentration gradient.

Question

​When hydrogen ions accumulate in the mitochondrial intermembrane space, what prevents them from moving back into the mitochondrial matrix without flowing through ATP synthase?
A)​The hydrophilic environment of the mitochondrial matrix repels hydrogen ions.
B)​The hydrophobic environment of the mitochondrial matrix repels hydrogen ions.
C)​Hydrogen ions combine with oxygen gas to form water, which cannot cross the lipid bilayer of the mitochondrial membrane.
D)​Hydrogen ions cannot cross the lipid bilayer of the mitochondrial membrane.
E)​Entering the matrix would require the ions to move against their concentration gradient.

Quizplus · Accepted Answer

Hydrogen ions cannot cross the lipid bilayer of the mitochondrial membrane. The mitochondrial inner membrane is impermeable to hydrogen ions due to its hydrophobic core composed of lipids, which prevents the ions from passing through. Therefore, they can only re-enter the mitochondrial matrix through the ATP synthase enzyme, which provides a channel for the hydrogen ions to cross the membrane and generate ATP.

​When Hydrogen Ions Accumulate in the Mitochondrial Intermembrane Space, What

When Hydrogen Ions Accumulate in the Mitochondrial Intermembrane Space, What