Chloroplast Structure

How do plants capture light energy ?

Energy does work Energy can move rocks uphill. The sun’s light energy is used to move H+ from a low to high concentration gradient

Stroma Thylakoid Space 1 st stage of photosynthesis: Light Reactions Sunlight transfers energy to chlorophyll a e- are excited and move releasing energy to move H+ to inside of thylakoid

PS 2 Electrons release stored E as they move from one molecule to another ( PS, ETC) The released e- is to used to create NADPH H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ PS 1 H+H+H+H+ e-e-e-e- NADP+H H+H+H+H+ e-e-e-e- Inside of Thylakoid Stroma PHOTOSYSTEM II W/ Chlorophyll a ETC NADPH

PrimaryProducts of Light Rxns Light Reactions Stroma Thylakoid Space NADP picks up e - and H + ETC ATPSynthase

Chemiosmosis H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ ATP Synthase Large concentration gradient of protons (H+) Protons cannot cross the membrane except through ATP Synthase (channel protein) ATP Synthase harnesses flow of protons to form ATP molecules ADPP ATP

Lake Mead represents potential energy such as many H+ stored in the thylakoid Hoover Dam is the thylakoid membrane with ATP synthase in it H+H+ H+H+ H+H+ H+H+ H+H+ Turbines represent the ATP synthase ATP

ATP Synthases Harnessing the Flow of Protons H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ H+H+H+H+ ADPP ATP ADPP ATP ATP Synthase

What influences the rate of photosynthesis? Independent variable LightTemperature Rate of Photosynthesis Independent Variable

Review Questions 1. What parts make up an ATP molecule? 2. How can a cell put together ADP and another phosphate to form ATP? 3. How can a cell build up a proton gradient (a difference in concentrations of protons across a membrane)? 4. Where is the high end of the concentration gradient established? 5. How can a cell energize electrons?