1. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Chapter 5 Introduction to Energy Transfer

2. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Energy The Capacity for Work –A dynamic state related to change –Its presence emerges when a change occurs

3. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition First Law of Thermodynamics Energy can not be created or destroyed, but is transformed from one form to another without being depleted. –Conservation of energy Illustrated as body transforms energy in food to heat, mechanical, and chemical energy

4. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Potential and Kinetic Energy Potential energy –Bound in a specific form Kinetic energy –Harnessing of potential energy –Biosynthesis results from harnessing energy Individual atoms are joined to synthesize biologic compounds

5. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Energy Processes Energy-releasing process –Exergonic Release energy to surroundings Energy-conserving process –Endergonic Store or absorb energy Coupled reactions –Exergonic drive endergonic

6. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Second Law of Thermodynamics The transfer of potential energy to kinetic energy in any spontaneous process always proceeds in a direction that decreases the capacity to do work. –Entropy is increased. –Eventually energy transforms to a less usable form of heat.

7. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Forms of Energy –Chemical –Mechanical –Heat –Light –Electric –Nuclear

8. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

9. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Interconversions of Energy Examples of energy conversions –Photosynthesis Captures energy that we utilize as food and oxygen –Cellular respiration Part of the energy released becomes conserved in compounds used for biologic processes

10. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Biologic Work in Humans Mechanical work –Muscle contraction –Cell division Chemical work –Synthesis of molecules Transport work –Diffusion –Active transport

11. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition The Rate of Bioenergetics Enzymes as biologic catalysts –Reduce required activation energy –Accelerate the rates of chemical reactions –Reaction rates depend upon pH Temperature Availability of substrates

12. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

13. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Enzymes Mode of action –Lock and key mechanism –Enzyme-substrate complex

14. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

15. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Coenzymes Nonprotein, organic substances Assist enzyme action by binding the substrate to the enzyme

16. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Enzyme Inhibition Competitive inhibitors –Substrates that closely resemble the target substrate but can not be changed by the enzyme –Bind to the enzyme’s active site Noncompetitive inhibitors –Do not resemble target substrate –Bind to a nonactive site, altering the enzyme

17. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Hydrolysis and Condensation Hydrolysis reactions –Catabolize complex organic molecules –Split chemical bonds by adding H + and OH − Digestion Condensation reactions –Reverse of hydrolysis Peptide bonds

18. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

19. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

20. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Oxidation and Reduction Reactions Oxidation – loss of electrons –Transfer of Oxygen Hydrogen Electrons Reduction – gain of electrons Redox reactions –Oxidation and reduction are coupled

21. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Mass Action Effect Chemical processes progress toward products with addition of reactants Addition of byproducts causes progression toward reactants Changing the concentration of a substance alters many different reactions

22. Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Measuring Energy Release Oxygen consumption is used in humans Oxygen is required for complete combustion of food –Metabolism requires oxidation of food –The rate of metabolism is measured by determining the volume of oxygen consumed