Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero Chapter 10 Photosynthesis

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Process That Feeds the Biosphere C

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Photosynthesis  plants, algae and some prokaryotes

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Autotrophs = Producers

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Heterotrophs = Consumers – Obtain their organic material from other organisms

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Sites of Photosynthesis in Plants The leaves of plants are the major sites of photosynthesis

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Sites of Photosynthesis in Plants The leaves of plants are the major sites of photosynthesis

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Sites of Photosynthesis in Plants The leaves of plants are the major sites of photosynthesis

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Chloroplast Structure

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Tracking Atoms Through Photosynthesis: Scientific Inquiry Photosynthesis: 6 CO H 2 O + Light energy  C 6 H 12 O O H 2 O What is oxidized? What is reduced? Cellular Respiration: C 6 H 12 O6 + 6O 2  6CO 2 + 6H 2 O + ATP

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Two Stages of Photosynthesis: A Preview Photosynthesis consists of two processes 1. The Light reactions 2. The Calvin cycle

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Two Stages of Photosynthesis: A Preview Photosynthesis consists of two processes 1. The Light reactions – Solar Energy  ATP and NADPH 2. The Calvin cycle – Use ATP and NADPH – CO2  Sugar

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The light reactions

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The light reactions

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Calvin Cycle

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Nature of Sunlight Light – Form of electromagnetic energy – Travels in waves

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The electromagnetic spectrum

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Photosynthetic Pigments: The Light Receptors Pigments= Substances that absorb visible light Reflected Light = the colors we see

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings What pigments (wavelengths of light) are used to drive photosynthesis?

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The absorption spectra of 3 types of pigments in chloroplasts

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chlorophyll a - Main photosynthetic pigment Chlorophyll b- Accessory pigment

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings What happens when chlorophyll absorbs light?

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings What happens when chlorophyll absorbs light?

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Isolated solution of chlorophyll  Illuminated = Fluoresce, gives off light and heat Figure B

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Photosystem: Reaction Center associated with Light-Harvesting Complexes Where and how does photosynthesis take place?

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Light Reactions!

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 2 Photosystems and 2 Electron Transport Chains

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Photosystem II 1. Light absorbed by chlorophyll  chlorophyll 680

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Photosystem II 1. Light absorbed by chlorophyll  chlorophyll electron excited  caught by primary electron acceptor

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Photosystem II 3. Enzyme splits H2O  O2 + H + + electrons Electrons pulled to chlorophyll 680

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Photosystem II and Electron transport chain 1 4. Electron pulled down electron transport chain 1= 5. Make ATP

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Photosystem I Electrons pulled by chlorophyll 700 in PS I

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Photosystem I 6. Light absorbed by chlorophyll in PS I  chlorophyll 700

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Photosystem I and Electron transport chain 2 7. Excited electron caught by primary electron acceptor and pulled down electron transport chain 2

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Photosystem I and Electron transport chain 2 8. NADP electrons and 1 H + = NADPH

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Mechanical analogy for the light reactions

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Chloroplasts and Mitochondria – Generate ATP by the same basic mechanism: Chemiosmosis – Compare/Contrast: 2. Movement of H+ (between what spaces, what direction?)

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 2 Photosystems and 2 Electron Transport Chains

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chloroplasts and Mitochondria – Generate ATP by the same basic mechanism: Chemiosmosis – Compare/Contrast: 2. Movement of H+ (between what spaces, what direction?)

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Concept 10.3 Calvin Cycle: – Uses ATP and NADPH to convert CO 2 to sugar – Occurs in the stroma

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The Calvin cycle has 3 phases 1. Carbon fixation 2. Reduction 3. Regeneration of the CO 2 acceptor

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The Calvin cycle: 1. Carbon fixation

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 2. Reduction

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 3. Regeneration of RuBP 1 5 3

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REVIEW! Ch. 10 Photosynthesis: What organisms? Where? Chloroplast structure Light reactions and Calvin cycle (where and what?) Light reactions  2 photosystems, 2 electron transport chains