Photosynthetic electron flow builds a proton gradient across the thylakoid to drive photophosphorylation.
Protons accumulate in the thylakoid lumen from water splitting and plastoquinone pumping; ATP synthase in thylakoid membranes uses the gradient. Per 3 H+ one ATP is made.
Chloroplast ATP synthase is similar to the mitochondrial one. The thylakoid lumen is acidic (about pH 4).
Remember: chemiosmosis is central in both respiration and photosynthesis.
Photosynthetic electron flow builds a proton gradient across the thylakoid to drive photophosphorylation.
Light Reactions and ATP Synthesis is one of the 53 topics in Metabolism & Bioenergetics. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Mitochondrial Uncoupling, Chemiosmosis, Oxidative Phosphorylation.
Uncouplers collapse the gradient and stop ATP synthesis.
Work through the Beginner topics in Metabolism & Bioenergetics first, such as Metabolism, Anabolism and Catabolism, ATP, then return to Light Reactions and ATP Synthesis. Intermediate topics assume the Beginner vocabulary.
The closest topics to Light Reactions and ATP Synthesis are Mitochondrial Uncoupling, Chemiosmosis, Oxidative Phosphorylation, Electron Transport Chain. Comparing them side by side is a good way to see how the ideas connect.
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Light Reactions and ATP Synthesis. To practise the whole of Metabolism & Bioenergetics, use the Metabolism & Bioenergetics quiz.
Light Reactions and ATP Synthesis: Photosynthetic electron flow builds a proton gradient across the thylakoid to drive photophosphorylation. Mitochondrial Uncoupling: Uncoupling proteins dissipate the proton gradient as heat, as in brown adipose tissue. Read both side by side and note what each one explains.
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Mitochondrial Uncoupling and explain the difference aloud. Finally, take the Metabolism & Bioenergetics quiz and come back to this page for any question you miss.
Uncoupling proteins dissipate the proton gradient as heat, as in brown adipose tissue.
⚡ Metabolism & BioenergeticsProtons flowing back through ATP synthase down their gradient drive the formation of ATP.
⚡ Metabolism & BioenergeticsATP synthesis driven by electron transport and the proton gradient across the inner membrane.
⚡ Metabolism & BioenergeticsProtein complexes in the inner mitochondrial membrane pass electrons to oxygen while pumping protons.
⚡ Metabolism & Bioenergetics