Energy and Living Organisms

1. Energy and Living Organisms • Living organisms require energy to perform functions. They: • Kidney cells: • to transports materials • Digestive tract: • break macromolecules • Heart: • to pump

2. Thermodynamics and Metabolism

4. Metabolism Metabolism: Anabolism: Catabolism:

5. Flow of Energy Energy: Energy can take many forms: mechanical electric current heat light All energy can be classified as: -kinetic energy: -potential energy:

6. Potential Energy • stored energy. • ___________________________________ • ___________________________________

8. Flow of Energy Potential energy stored in chemical bonds can be transferred from one molecule to another by way of electrons. oxidation: reduction: redox reactions

9. Kinetic Energy • Energy of motion • ________________________________________ • ________________________________________

10. http://www.youtube.com/watch?v=Jnj8mc04r9E

11. Thermodynamics • Study of heat and energy flow within chemical reactions

12. Laws of Thermodynamics First Law of Thermodynamics – For example: sunlight energy chemical energy photosynthesis

13. Exercise to lose weight • produce heat and you sweat • heats the air around you. • When you eat a pizza • energy from the chemical bonds in the bread, cheese, etc. is broken down • converted into ATP molecules through cellular respiration.

14. Enthalpy • ______________________________________________________________________________ • The enthalpy change (ΔH) • amount of heat released or absorbed when a chemical reaction occurs at a constant pressure. • ΔH formation = _____________________________

15. Potential Energy Diagram • Reactants: • Activation energy (Ea): • Transition state: • Products:

16. Exothermic Reactions • some of the reactant's potential energy is released into the surroundings as heat. • enthalpy of the products is ____________________ • energy is _____________ • ΔH is ____________

17. Exothermic Reaction http://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/019_THERMITE.MOV

18. Endothermic Reaction

19. Endothermic Reactions

21. Entropy

22. Laws of Thermodynamics Second Law of Thermodynamics: entropy: The 2nd Law of Thermodynamics states that entropy is always increasing.

24. Laws of Thermodynamics Free energy: -denoted by the symbol G (Gibb’s free energy) enthalpy: free energy = enthalpy – (entropy x temp.) G = H - TS

25. Laws of Thermodynamics • Chemical reactions can create changes in free energy. • When products contain more free energy than reactants DG is positive. • When reactants contain more free energy than products DG is negative.

26. Laws of Thermodynamics Chemical reactions can be described by the transfer of energy that occurs: endergonic reaction: exergonic reaction:

28. Laws of Thermodynamics Most reactions require some energy to get started. activation energy: catalysts:

30. Respiration C6H12O6 + O2 → CO2 + H2O + Energy (as ATP)            ΔG = - 2870 kJ/mol of glucose • release of energy • an increase in entropy • This reaction tends to proceed spontaneously.  

31. Photosynthesis Photosynthesis Chemical Equation CO2 + H2O + Energy → C6H12O6 + O2 ΔG = + 2870 kJ/mol of glucose • energy is absorbed • a decrease in entropy • This reaction does not proceed spontaneously as energy is needed to drive the reaction.    

32. Energy Currency of Cells ATP= adenosine triphosphate ATP structure:

34. Section 9.1 P A P P Adenosine Triphosphate (ATP)

35. Section 9.1 P P P Adenosine Triphosphate (ATP) • Mono = One phosphate group • Di = Two phosphate groups • Tri = three phosphates groups A

36. Section 9.1 The battery of the cell

37. Energy Currency of Cells When the bond between phosphates is broken: ATP ADP + Pi energy is released ADP = adenosine diphosphate Pi = inorganic phosphate This reaction is reversible.

39. Energy Currency of Cells

40. Section 1.3, p.68 1, 2 , 5 , 10 , 11