Question

The electron transport chain pumps protons:

A. from the intermembrane space to the matrix.
B. from the matrix to the intermembrane space.
C. from the matrix to the cytosol.
D. from the matrix to the endoplasmic reticulum

Answer 1

The electron transport chain pumps protons from the mitochondrial matrix to the intermembrane space to generate ATP.

Step-by-step explanation:

The electron transport chain pumps protons from the mitochondrial matrix to the intermembrane space. This process is essential for the synthesis of ATP during oxidative phosphorylation. In the mitochondria, complexes I, III, and IV of the electron transport chain use the energy released from electrons to pump protons (H+) across the inner mitochondrial membrane, establishing an electrochemical gradient. This gradient is then utilized by ATP synthase to generate ATP as protons flow back into the matrix. Therefore, the correct answer is B. from the matrix to the intermembrane space.