Fig. 10.1 Photosynthesis

Outline - Photosynthesis 1. An Overview of Photosynthesis & Respiration 2. Autotrophs, photoautotrophs, and producers 3. Electromagnetic Spectrum & light energy 4. Chloroplast structure and location in a leaf 5. Photosynthetic pigments: Chlorophylls & Carotenoids 6. Chemical Reactions of Photosynthesis Light Harvesting Sugar Building 8. Photosynthesis Review 9. Variation in harvesting CO2 C3, C4 and CAM

Overview of Photosynthesis & Respiration

Autotrophs & Photoautotrophs are Producers Chemoautotrophs Sulfolobus Conditions: pH 1.0 at 95C Habitat: Hot springs, mud pots Oxidizes sulfur to sulfuric acid Photoautotrophs - sun Chemoautotrophs - inorganic sources NH3, H2S and Sulfur Photoautotrophs Plants Algae Cyanobacteria

Electromagnetic Spectrum Increasing energy Increasing wavelength 0.1 nm 1 nm 10 nm 1000 nm 0.1 cm 1 cm 1 m 100 m X rays UV light Infrared Gamma rays Radio waves Visible light 400 nm 430 nm 500 nm 560 nm 600 nm 650 nm 740 nm

Light Absorption During Photosynthesis Sun White Light

Pigments of Photosynthesis Chlorophylls (green) Carotenoids (orange/yellow)

Absorption Spectrum of Photosynthetic Pigments Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Absorption Spectrum of Photosynthetic Pigments Chlorophyll a, Chlorophyll b & Carotenoids Carotenoid Chlorophyll b Chlorophyll a Amount of light absorption 400 450 500 550 600 650 700 Wavelength (nm)

Plant Cell Chloroplasts

Chloroplast Structure Fig. 10.2bb (TEArt) Inner membrane Thylakoid Outer membrane Granum Stroma

Photosynthesis Equation Photosynthesis Equation Photosynthesis is a redox process H2O is oxidized and CO2 is reduced Reduction  6 CO2 6 H2O C6H12O6  6 O2 Oxidation

Photosynthesis is Light Harvesting & Sugar-Building Fig. 10.2db (TEArt) Photosynthesis is Light Harvesting & Sugar-Building Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Photosystem CO2 H20 Light Harvesting Light-Dependent Reactions O2 Carbohydrates Thylakoid Light Independent Reactions Sugar Building Calvin Cycle Light Harvesting ADP NADPH ATP NADP+ Sugar Building Stroma

Photosynthesis: Light Harvesting by Photosystems Thylakoid membrane Fig. 10.6a (TEArt) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sun Chlorophyll molecules and Carotenoids in protein complex Thylakoid membrane Reaction Center Chlorophyll

Photosynthesis: Light Harvesting by Photosystems Fig. 10.10 (TEArt) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Electron Acceptor Reaction center chlorophyll e- Photon e- Chlorophyll molecules Photosystem

Photosystem I Reduces NADP+

Photosystem II Supplies Electrons to PSI PSII Reaction Center

Water Splitting & Oxygen Production Photosystem II Water Splitting & Oxygen Production Photosystem II

Photosystem II Supplies Electrons to PSI

Photosystem II Supplies Electrons to PSI PSII Reaction Center

Thylakoid Structure Thylakoid Fig. 10.6b (TEArt) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Thylakoid Structure Thylakoid

Chemiosomosis & ATP Synthesis in Chloroplasts Fig. 10.16b (TEArt) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chemiosomosis & ATP Synthesis in Chloroplasts H+ Photon Stroma H+ ADP ATP Stroma e- Q H2O H+ Thylakoid space H+ H+ H+ _ 1 2 H+ 02 2H+ Photosystem II b6-f complex ATP synthase

Photosynthesis: Light Harvesting by Photosystems Fig. 10.14 (TEArt) Photosynthesis: Light Harvesting by Photosystems Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Excited reaction center Ferredoxin e– Fd NADP reductase Plastoquinone Reaction center e– e– NADPH NADP+ + H+ Q b6-f complex Plastocyanin Reaction center pC Photon Energy of electrons H+ e– Water- P 700 Photon splitting enzyme P680 H2O __ 1 2H+ + O2 2 Photosystem I NADP reductase Photosystem II b6-f complex

Light Reactions Mechanical Analogy H2O provides electrons electron transport chain reduce NADPH ATP synthesized Oxygen released ATP e– e– e– NADPH e– e– Photon e– Photon H2O O2 e- Photosystem II Photosystem I Figure 7.8B

Summary of Light Harvesting Reactions H2O provides electrons for electron transport chain NADP  reduced to NADPH ATP synthesized by chemiosmosis Oxygen released

Sugar-Building & the Calvin Cycle

Sugar Building – The Calvin Cycle Fig. 10.17 (TEArt) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sugar Building – The Calvin Cycle 3 1 2 CO2 P RuBP 3-phospho glycerate RuBP ATP NADPH Glyceraldehyde 3-phosphate Glyceraldehyde 3-phosphate Glucose Carbon Dioxide Fixation Carbon Reduction Regeneration of RuBP

PHOTOSYNTHESIS REVIEW CO2 Light H2O Chloroplast NADP+ ADP + P RUBP Photosystem II Light Reactions CALVIN CYCLE 3-PGA Thylakoid membranes Photosystem I ATP Stroma NADPH Cellular respiration G3P Cellulose Starch O2 Sugars Other organic compounds Figure 7.11

END Photosynthesis