Producers and Consumers

1. Producers and Consumers • Autotrophs (self-feeders): • Make their own organic matter from inorganic nutrients. • Heterotrophs (other-feeders): • Organisms that cannot make organic molecules from inorganic ones.

2. Energy Flow and Chemical Cycling in the Biosphere Sunlight energy enters ecosystem CO2 (Carbon dioxide) C6H12O6 (Glucose) Photosynthesis + + O2 (Oxygen) H2O (water) Cellular respiration drives cellular work ATP Heat energy exits ecosystem

3. Photosynthesis • Photosynthesis: • Is used by plants, some protists, and some bacteria • Transforms light energy into chemical energy • Uses carbon dioxide and water as starting materials Light energy 6 CO2 6 O2 C6H12O6 6 H2O Photo- synthesis Carbon dioxide Water Oxygen gas Glucose

4. Photosynthesis • Organisms that use photosynthesis are: • Photosynthetic autotrophs • The producers for most ecosystems PHOTOSYNTHETIC AUTOTROPHS Plants (mostly on land) Photosynthetic Protists (aquatic) Photosynthetic Bacteria (aquatic) LM Forest plants Kelp, a large alga Micrograph of cyanobacteria

5. Photosynthesis found b/w lower and upper epidermis

6. Photosynthesis CO2 H2O Light Chloroplast NADP+ ADP P Calvin cycle Light reactions ATP NADPH O2 Sugar (C6H12O6)

7. Photosynthesis *photon *Photons are absorbed by pigment molecules

8. Why Green? Light Reflected light Chloroplast Absorbed light Transmitted light

9. Light-harvesting complexes of the thylakoid membrane

10. Electron Flow

11. Organization of light reaction machinery

12. Chemiosmosis: A Comparison

13. Calvin cycle (Carbon Fixation)

14. Photosynthesis

15. Alternative Pathways ALTERNATIVE PHOTOSYNTHETIC PATHWAYS CAMPathway (example: pineapple) C4 Pathway (example: sugarcane) Cell type 1 CO2 CO2 Night Four-carbon compound Four-carbon compound CO2 CO2 Cell type 2 Calvin cycle Calvin cycle Day Sugar Sugar CAM plant C4 plant