Question

The electron-transport chain pumps protons in which direction?

a) From the matrix to the cytosol
b) From the cytosol to the intermembrane space
c) From the intermembrane space to the matrix
d) From the intermembrane space to the cytosol
e) From the matrix to the intermembrane space

Answer 1

The electron-transport chain pumps protons from the matrix to the intermembrane space.

Step-by-step explanation:

The electron-transport chain pumps protons from the matrix to the intermembrane space.

In eukaryotic cells, the electron transport chain is located in the inner mitochondrial membrane. As high-energy electrons are transported along the chain, some of their energy is used to pump hydrogen ions from the matrix into the intermembrane space. This creates an electrochemical gradient that can ultimately be used to produce ATP through chemiosmosis.

For example, in Figure 11.7, it shows that during the electron transport chain, protons are pumped from the mitochondrial matrix to the intermembrane space, and oxygen is reduced to form water.