Thylakoid Lumen

The thylakoid lumen is the part of the chloroplast enclosed by the thylakoid membrane (Figure 17.15). During photosynthesis, electrons are pumped into the thylakoid lumen from the stroma, forming a proton gradient. Movement of the protons out of the thylakoid lumen through the CF 0-CF 1 complex back to the stroma provides the driving force for photophosphorylation, the process of making ATP in photosynthesis. A similar mechanism is responsible for ATP synthesis in oxidative phosphorylation.

See also: Thylakoid Membrane, Figure 17.4c, The Chloroplast, Chloroplast Anatomy, Stroma, Grana, CF 0-CF 1 Complex, Figure 17.16, Oxidative Phosphorylation