© 2011, 2007, 2002, 1988 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ Practical Horticulture 5 th edition By Margaret J. McMahon, Anton M. Kofranek and Vincent E. Rubatsky tab Chapter 11 - Photosynthesis and Respiration The carbon cycle is the means by which energy from the sun is captured, converted to chemical energy & released to support all living organisms. –The carbon cycle starts with photosynthesis Carbohydrates are synthesized from CO 2 and water. –Releasing oxygen in the process. –The respiration process breaks down the bonds in molecules, releasing energy, CO 2 and water vapor into the atmosphere. The energy released fuels all the biological processes necessary for life. The Carbon Cycle & Energy Transfer

© 2011, 2007, 2002, 1988 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ Practical Horticulture 5 th edition By Margaret J. McMahon, Anton M. Kofranek and Vincent E. Rubatsky tab Chapter 11 - Photosynthesis and Respiration The Carbon Cycle & Energy Transfer

© 2011, 2007, 2002, 1988 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ Practical Horticulture 5 th edition By Margaret J. McMahon, Anton M. Kofranek and Vincent E. Rubatsky tab Chapter 11 - Photosynthesis and Respiration Photosynthesizing = Autotrophs Cannot synthesize = Heterotrophs –Heterotrophs must consume autotrophs—or other heterotrophs that have fed on autotrophs—to get the energy-releasing carbohydrates. Plants play the leading role in the carbon cycle. –Without them, no other life can survive. The Carbon Cycle & Energy Transfer

© 2011, 2007, 2002, 1988 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ Practical Horticulture 5 th edition By Margaret J. McMahon, Anton M. Kofranek and Vincent E. Rubatsky tab Chapter 11 - Photosynthesis and Respiration Carbon can form up to four bonds, each bond representing two electrons. ethane The Carbon Cycle & Energy Transfer

© 2011, 2007, 2002, 1988 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ Practical Horticulture 5 th edition By Margaret J. McMahon, Anton M. Kofranek and Vincent E. Rubatsky tab Chapter 11 - Photosynthesis and Respiration Bonds formed by carbon with another carbon or other elements have sufficient strength to make them relatively stable. –No other element has this ideal combination of share ability of electrons plus stability of the bonds formed. The Carbon Cycle & Energy Transfer

© 2011, 2007, 2002, 1988 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ Practical Horticulture 5 th edition By Margaret J. McMahon, Anton M. Kofranek and Vincent E. Rubatsky tab Chapter 11 - Photosynthesis and Respiration A basis of biochemical reaction is electron (energy) transfer between molecules (oxidation/reduction). –Reduced compounds easily donate electrons to other compounds; oxidized molecules easily accept electrons. Carbon is at the center of this process because it is so versatile in donating and accepting electrons. –Transfer of electrons from reduced to oxidized carbon compounds drives all of metabolism & underlies life itself. The Carbon Cycle & Energy Transfer

© 2011, 2007, 2002, 1988 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ Practical Horticulture 5 th edition By Margaret J. McMahon, Anton M. Kofranek and Vincent E. Rubatsky tab Chapter 11 - Photosynthesis and Respiration Photosynthesis is the process of converting oxidized carbon (CO 2 ) to reduced carbon—carbohydrate or C(H 2 O). The Carbon Cycle & Energy Transfer

© 2011, 2007, 2002, 1988 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ Practical Horticulture 5 th edition By Margaret J. McMahon, Anton M. Kofranek and Vincent E. Rubatsky tab Chapter 11 - Photosynthesis and Respiration Respiration is the process of converting reduced carbon to oxidized carbon to generate other forms of energy that are central to the function of living organisms The Carbon Cycle & Energy Transfer