Although compartmentalization allows cells to perform a variety of functions, there can be energetic costs to compartmentalization. In particular, cells expend energy to move certain molecules across membranes. In the mitochondria, the transmembrane gradient established by the electron transport chain plays an important role in the movement of molecules across the mitochondrial inner membrane. Which of the following processes involve directly expending this gradient to move molecules into the matrix? (select two answers)
a. import of proteins into the mitochondrial matrix coupled to ATP hydrolysis
b. antiport of malate into the matrix and a -ketoglutarate out of the matrix
c. antiport of glutamate into the matrix and aspartate out of the matrix
d. symport of inorganic phosphate and hydrogen ions into the matrix
e. symport of pyruvate and hydrogen ions into the matrix