Lecture 35 – Photosynthesis and Ligands November
• There was a question as to whether the O pro2uced in photosynthesis was from carbon dioxide
• Cyanobacteria, which have a photosynthetic pigment known as bacteriorhodopsin were used to.
• These bacteria produce sulfur from H S instead of oxygen like photosynthesis.
• From this it was established that the O p2oduced by photosynthesis is derived from the water.
• Thylakoids - Uses a proton gradient to produceATP using anATPase, protons flow out of the
thylakoid lumen into the stroma.
• This producesATP, NADPH, and O 2
• Researcher used 2D Paper Chromatography and found that spots on the paper were in fact
• Calvin administered radioactive sugar to plants and flashed the plants with light
• 3-Phospho-glycerate was one of the first sugars identified.
• 3-Phospho-glycerate was formed by adding CO to a 5-2arbon sugar (ribulose-bis-phosphate,
RuBP), forming a 6-carbon inter-mediate that then split in half to form two 3-Phospho-glycerate
• This reaction is carried out by an enzyme, ribulose bisphosphate carboxylase (rubisco), which is
the most common protein in the world.
• Through the Calvin-Benson cycle, rubisco helps create sugar and more ribulose bisphosphate
• Light causes ATP and NADPH to be formed in the stroma of the chloroplast.
• ATP goes to the Calvin-Benson Cycle, which makes sugar that the plant often converts into
• In low CO e2vironments (such as when the stomae cannot open fully), these plants use a
system that converts CO to2a four carbon unit until it