Figure 5.6 Chlorophyll H2C CH H3C CH2CH3 Chloroplast N N Mg Thylakoid CO2CH3 O C O Thylakoid membrane CH2 CH C–CH3 Photosystem CH2 CH2 Light energy CH2 HC–CH3 CH2 Hydrophobic tail CH2 CH2 HC–CH3 CH2 CH2 Antenna pigments CH2 HC-CH3 Reaction center chlorophyll CH3

Light reactions Carbon reactions Figure 5.7 H2O CO2 Light Chloroplast ATP Light reactions NADPH Carbon reactions NADP+ ADP O2 Suger

Figure 5.8 Photosystem II Electron transport chain Photosystem I Light energy H+ NADP+ + H+ NADPH Light energy Reaction center Chlorophyll a H+ 2e- 5 Stroma 1 2e- 2e- 6 P700 Antenna pigments 3 Reaction center chlorophyll a P680 H2O 2 electrons H+ 2 1/2 O2 + 2H+ H+ H+ Thylakoid space Light H2O Chloroplast CO2 4 Stroma ATP synthase ATP H+ Light reactions NADPH Carbon reactions NADP+ ADP Chemiosmotic phosphorylation ADP + P ATP O2 O2 Sugar

Figure 5.9 ( ) 1 4 2 3 Light Chloroplast Rubisco enzyme H2O CO2 Chloroplast ATP Light reactions NADPH Carbon reactions NADP+ ADP O2 Sugar 3 CO2 Rubisco enzyme CARBON FIXATION 3 P P ( 3 P P ) RuBP 1 Carbon dioxide is added to RuBP, creating an unstable molecule. Unstable intermediates REGENERATION OF RuBP 6 P PGAL SYNTHESIS PGA From light reactions 4 RuBP is regenerated by rearranging the remaining molecules. 2 The unstable intermediate splits to form PGAL 6 ATP 3 ATP 6 NADPH 6 NADP+ + 6 H+ 3 ATP 6 ADP + 6 P 5 P 6 P PGAL PGAL 3 PGAL molecules are combined to form glucose, which is used to form starch, sucrose, and other organic molecules. PGAL from other turns of the Calvin cycle 1 P PGAL Sugar

Figure 5.14 Leaf Cell Chloroplast Granum Light reactions (in thylakoid membranes) Granum Stroma Light energy Light energy Chlorophyll NADP+ + H+ H+ NADPH H2O H+ 1/2 O2 + 2H+ H+ H+ 3 CO2 H+ Rubisco enzyme ADP + P ATP Carbon Reactions (in stroma) ATP ADP + P NADPH NADP+ + H+ ATP ADP + P 1 P PGAL Glucose, starch, sucrose

Figure 5.15 Photosynthesis occurs in two stages Light reactions produce Carbon reactions is energy source for release as waste product is electron source for is electron source for produce ATP is carbon source for H2O O2 NADPH is energy source for CO2 Sugar Light