Metabolism & Energy Transfer - Slides PDF

Metabolism & Energy Transfer 1 1st Law of Thermodynamics 2 First Law of Thermodynamics Conservation of energy Energy cannot be created or destroyed but, instead, transforms from one form to another without being depleted Dictates that the body does no...

Metabolism & Energy Transfer 1 1st Law of Thermodynamics 2 First Law of Thermodynamics Conservation of energy Energy cannot be created or destroyed but, instead, transforms from one form to another without being depleted Dictates that the body does not produce, consume, or use up energy, but it transforms it from one form into another as physiologic systems undergo continual change Fig. 5.4. McArdle et al. 2015. Exercise 2 Physiology… LWW  Metabolism Terminology 3 energy: The ability to perform work. bioenergetics: The flow of energy in a biological system; the conversion of macronutrients into biologically usable forms of energy. endergonic reactions: Reactions that store or absorb energy and include anabolic processes. exergonic reactions: Energy‐releasing reactions that are generally catabolic. coupled reactions: Free energy from exergonic reactions serve to drive endergonic reactions. Fig. 5.2. McArdle et al. 2015. Exercise Physiology… LWW Anabolic vs. Catabolic Processes 4 Reactants or Fig. 2.6. McArdle et al. Products 2015. Exercise Substrates Enzyme Physiology… LWW Exergonic rxns Endergonic rxns Energy Yielding Macronutrients 5 Food Source Net kcal (per g) Carbohydrate ~4 Fat ~9 Protein ~4 Not all of the kcals can be absorbed / stored. Calories in food represents a form of potential work to be used by our bodies to do work and produce heat Types of Work 6 Review Questions 7  How can you apply the First Law of Thermodynamics to weight management?  Calculate the amount of kcals in a given food item if provide the grams of each macronutrient.  How many kcals in a food with 5g of carbs & 3 g of fat?  Identify the substrates and products within specific endergonic, exergonic, anabolic, and catabolic reactions.  Forexample, what is the product of the exergonic reaction for the creatine kinase enzyme during high‐intensity exercise? PCr + ADP → Cr + ATP What is the substrate of the anabolic reaction for that same enzyme? Figure & Notes References 8 McCardle, Katch, Katch. Exercise Physiology: Nutrition, Energy, and Human Performance, 8th Edition. Wolters Kluwer Health, 2015. Kenney, Wilmore, & Costill. Physiology of Sport & Exercise, 5th Edition. Human Kinetics, 2012. Powers & Howley. Exercise Physiology: Theory & Application to Fitness and Performance, 8th Edition. McGraw‐Hill, 2011. Williams. Nutrition for Health, Fitness, & Sport, 9th Edition. McGraw‐Hill Education, 2008.