8. Respiration

Chemiosmotic creation of ATP is driven by:

a) Phosphate transfer through the plasma membrane.

b) Potential energy of the H⁺ concentration gradient created by the electron transport chain.

c) Substrate-level phosphorylation in the mitochondrial matrix.

d) Large quantities of ADP in the mitochondrial matrix.

The electron transport chain pumps H⁺ ions into which location of the mitochondria?

a) Mitochondrial intermembrane space. 

b) Mitochondrial matrix.

c)  Mitochondrial inner membrane.

d) The H⁺ ions are pumped out of the mitochondria.

Continue your comparison of electron transport and chemiosmosis in mitochondria and chloroplasts. In each case, a. where do the electrons come from? b. how do the electrons get their high potential energy? c. what picks up the electrons at the end of the chain? d. how is the energy released as electrons are transferred down the electron transport chain used?

For a short time in the 1930s, some physicians prescribed low doses of a compound called dinitrophenol (DNP) to help patients lose weight. This unsafe method was abandoned after some patients died. DNP uncouples the chemiosmotic machinery by making the inner mitochondrial membrane leaky to H+. Explain how this drug could cause profuse sweating, weight loss, and possibly death.