Introduction• Poison ivy contains urushiol, a chemical that maycause itchy and oozing blisters that can last forweeks.• Like all plants, poison ivy produces energy for itsgrowth by photosynthesis, the process thatconverts light energy to the chemical energy ofsugar.© 2015 Pearson Education, Inc.Introduction• Photosynthesis• removes CO2from the atmosphere and• stores it in plant matter.• The burning of sugar in the cellular respiration ofalmost all organisms releases CO2 back to theenvironment.© 2015 Pearson Education, Inc.2019/11/192© 2015 Pearson Education, Inc.Figure 7.0-1© 2015 Pearson Education, Inc.Figure 7.0-2Chapter 7: Big IdeasAn Introduction toPhotosynthesisThe Light Reactions:Converting Solar Energyto Chemical EnergyThe Global Significanceof PhotosynthesisThe Calvin Cycle:Reducing CO2to Sugar© 2015 Pearson Education, Inc.AN INTRODUCTION TO PHOTOSYNTHESIS2019/11/1937.1 Photosynthesis fuels the biosphere• Plants are autotrophs, which• sustain themselves,• do not usually consume organic molecules derivedfrom other organisms, and• make their own food through the process ofphotosynthesis, in which they convert CO2 andH2O to sugars and other organic molecules.© 2015 Pearson Education, Inc.7.1 Photosynthesis fuels the biosphere• Photoautotrophs use the energy of light toproduce organic molecules.• Chemoautotrophs are prokaryotes that useinorganic chemicals as their energy source.• Heterotrophs are consumers that feed on plantsor animals or decompose organic material.