Question

According to the chemiosmotic theory (chemiosmotic coupling), the energy required to move protons from the mitochondrial matrix to the intermembrane space against a concentration gradient comes most directly from photons of red or blue light A the hydrolysis of ATP B the breakdown of high-energy fatty acids in the mitochondrial matrix C electrons flowing along the electron transport chain D substrate-level phosphorylation E Submit

Answer 1

According to the chemiosmotic theory (chemiosmotic coupling), the energy required to move protons from the mitochondrial matrix to the intermembrane space against a concentration gradient comes most directly from:____________

a) photons of red or blue light

b) the hydrolysis of ATP

c) the breakdown of high-energy fatty acids in the mitochondrial matrix

d) electrons flowing along the electron transport chain

e) substrate-level phosphorylation

Answer:

d) electrons flowing along the electron transport chain

Explanation:

NADH and FADH2 give electrons to the proteins of the electron transport chain. The part of the energy of electrons is used to pump the electrons from the matrix into the intermembrane space. This creates a proton concentration gradient which in turn drives the process of ATP synthesis.  Here, the process of ATP synthesis is driven by the electrochemical gradient generated during the oxidation of reducing powers. Therefore, the process of called chemiosmotic coupling.