Photosynthesis

The overview Photosynthesis Light reaction Photosystems 1 and 2 Needs H2O, light, NADP, ADP Products are O2, NADPH, and ATP Dark reaction Calvin cycle Needs CO2, NADPH, and ATP Main product is glucose

Where does photosynthesis occur? Leaves Chloroplasts Thylakoid Thylakoid membrane

Picture of location

The steps to make NADPH Sunlight delivers photons (light energy) through chlorophyll in Photosystem II Sunlight delivers photons (light energy) through chlorophyll in Photosystem II Chlorophyll passes this light energy until it collides with an electron Chlorophyll passes this light energy until it collides with an electron Electron is excited by extra energy and moves out of Photosystem II Electron is excited by extra energy and moves out of Photosystem II Electron is carried by proteins in the electron transport chain Electron is carried by proteins in the electron transport chain

The steps for NADPH continued Electron reaches photosystem I reaction center and runs out of energy Electron reaches photosystem I reaction center and runs out of energy Light energy is again passed through chlorophyll in this area and hits the electron Light energy is again passed through chlorophyll in this area and hits the electron Electron is excited again, passes through another electron transport chain Electron is excited again, passes through another electron transport chain Electron finally reaches NADP + and converts it to NADPH Electron finally reaches NADP + and converts it to NADPHNADPH

Steps for O 2 Production Water enters thylakoid space at photosystem II Water enters thylakoid space at photosystem II Water is split into electrons and protons and O 2 Water is split into electrons and protons and O 2 Electrons replace those used in light reaction at photosystem II Electrons replace those used in light reaction at photosystem II Protons remain in space to be used for ATP Protons remain in space to be used for ATP O 2 is given off to atmosphere O 2 is given off to atmosphere O 2 O 2

Steps to make ATP Ion pumps force extra protons against concentration gradient to thylakoid space to join those made when water was split Ion pumps force extra protons against concentration gradient to thylakoid space to join those made when water was split Protons come back across the thylakoid membrane through protein channel called ATP synthase Protons come back across the thylakoid membrane through protein channel called ATP synthase Protons join P with ADP to make ATP Protons join P with ADP to make ATPATP