Substrate-Level
Phosphorylation (SLP) involves the transfer of phosphate from
a high energy molecule to ADP, with the aid of an enzyme.
Chemiosmosis
requires a phospholipid bilayer, a proton pump, protons and ATPase.
Energy from food
molecules is used to pump protons out through a proton pump (intrinsic
protein). This creates a concentration of protons (H+) outside.
ATPase has a channel
that allows for the facilitated diffusion of protons back in through the
membrane. This activates ATPase, which in turn catalyzes the formation
of ATP.
In summary, the energy
stored in food molecules is transferred to a proton pump which creates
a proton gradient across the membrane. This gradient is used to activate
the enzyme ATPase. ATPase catalyzes the formation of ATP