KINE 2P90 Lecture 1 Bioenergetics 1 PDF

KINE 2P90 Lecture 1 Bioenergetics 1 Friday September 6, 2024 ty 1 Before Bioenergetics….. Section 1: Chapters 0-2 Physiology of Exe...

KINE 2P90 Lecture 1 Bioenergetics 1 Friday September 6, 2024 ty 1 Before Bioenergetics….. Section 1: Chapters 0-2 Physiology of Exercise Chapter 0 (pp. 2 - 24) Introduction to Exercise Physiology Chapter 1 (pp. 25 - 38) Common Measurements in Exercise Physiology Chapter 2 (pp. 39 - 49) Control of the Internal Environment ….. review on your own 2 Bioenergetics 1 Chapter 3 Bioenergetics (pp. 50 – 79) CELL STRUCTURE (51) (review on own) BIOLOGICAL ENERGY TRANSFORMATION (51) Cellular Chemical Reactions (52) Oxidation-Reduction Reactions (54) Enzymes (55) today FUELS FOR EXERCISE (58) Carbohydrates (58) Fats (59) Next lecture Proteins (59) HIGH ENERGY PHOSPHATES (60) 3 1  Chapter 3: Bioenergetics Highlighted Topics: Research Focus 3.1 (Mitochondria) The Winning Edge 3.1 (Creatine Supplementation) A Closer Look (3.2) Lactic Acid or Lactate? A Closer Look 3.3 (NADH Shuttle) A Closer Look 3.4 (Beta Oxidation) A Closer Look 3.5 (ATP Balance Sheet) 4 Chapter 3: Bioenergetics We Wont Cover in Class: Clinical Applications 3.1 A Look Back (Hans Krebs) Research Focus 3.2 (Free Radical Generation) Ask the Expert 3.1 STUDY ACTIVITIES (pg. 77) Good Exam Questions! Review on your own Answers provided during office hours 5 Figure 3.1 the muscle fiber is an “energy transducer”” (well similar) 6 2  Details about the two populations of mitochondria in skeletal muscle 7 (foods) (ATP) 8 Biological Energy Transformation ❑ process of converting foodstuffs into energy* ▪ starting “fuels” include: fats, carbohydrates & proteins (also known as substrates) ▪ these fuels converted to a common high energy compound adenosine triphosphate (ATP) all external and internal work powered by ATP external work ❑ internal work includes: ▪ ion trafficking across membrane ▪ regulating calcium levels You, using ATP ▪ actin-myosin interactions Image result for INTRACELLULAR WORK ▪ protein synthesis Your cell, using ATP * energy defined as ability to do work 9 3  Cellular Chemical Reactions free energy in food ► metabolic pathways ► no direct link! ► extract energy contained by food ► energy used to make ATP ATP supplies the energy needed to do all biological work (internal and external) 10 Cellular Chemical Reactions (Fig 3.3) ► example of a metabolic pathway oxidizing substrate (glucose) to products (CO2 and H2O) to make energy (ATP) 60-70% (or respiration) 11 Oxidation-Reduction Reactions ❑ Oxidation ▪ removal of an electron (as H+) ❑ Reduction ▪ addition of an electron (as H+) ❑ this is how energy is transferred within the cell ▪ from molecule to molecule ❑ oxidation and reduction are always coupled reactions ▪ one cannot occur without the other ▪ the molecule that donates H+ is the reducing agent ▪ NADH and FADH are most important examples 12 4  REDOX REACTIONS 13 REDOX REACTIONS Involving NAD & NADH (Fig 3.5) dehydrogenase dehydrogenase “Redox reaction” 14 Coupled Reactions (Fig 3.4) Exergonic (energy yielding) reactions power endergonic (energy requiring) reactions key reactions? 15 5  Cellular Chemical Reactions ❑ Endergonic (or endothermic) reactions ▪ energy requiring reactions ▪ e.g., storing glycogen, protein ANABOLIC ❑ Exergonic (or exothermic) reactions ▪ reactions that release energy ▪ e.g. cellular respiration CATABOLIC ❑ these reaction types are coupled ▪ anabolic catabolic 16 Enzymes ❑ proteins that catalyze metabolic reactions ▪ lower the “activation energy” required for reaction to proceed o speed up reactions by x1000 reactions are already thermodynamically favorable ❑ specific enzymes for specific pathways (Table 3.2) ▪ enzyme activity controls bioenergetics o these are rate limiting enzymes control flux though pathways » e.g. PFK and glycolysis ❑ catalytic activity of rate limiting enzymes highly regulated ▪ by various factors via allosterism (+ or -) 17 Example of a Rate-Limiting Enzyme (Fig 3.22) metabolic pathway Which is most Example important? of end product inhibition How is (via allosterism) pathway regulated?? 18 6 19 Enzymes lower the energy of activation (Fig 3.6) ❑ increase catalytic rate (↓ activation energy) ▪ increase rate of disappearance of substrate ▪ increase rate of appearance of products ❑ enzymes do not alter energy release ▪ enzymes are not consumed in the reaction 20 Lock-and-Key Model Enzyme Action (Fig 3.7) Accounts for Specificity of Enzyme Activity a) Substrate A and B approach the active site on the enzyme. b) Substrates fit into the active site, forming enzyme-substrate complex. c) The enzyme releases the products C and D 21 7  Factors That Alter Enzyme Activity ❑ Temperature ▪ a small rise in body temperature ↑ enzyme activity ▪ Figure 3.8 ❑ pH ▪ cellular ph is 7.2; blood pH is 7.4 ▪ changes in pH from this range reduce enzyme activity ▪ Figure 3.9 ❑ Exercise? ▪ highlights importance of homeostatic control ▪ consequences of failure? o fatigue or cell death! 22 Diagnostic value of measuring enzyme levels in the blood-examples 23 Bioenergetics 1 Section 1: Chapter 3 Bioenergetics (pp. 40 – 64) CELL STRUCTURE (48) (review on own) today BIOLOGICAL ENERGY TRANSFORMATION (48) Cellular Chemical Reactions (49) Oxidation-Reduction Reactions (51) Enzymes (52) FUELS FOR EXERCISE (pp. 55) Carbohydrates (55) Fats (56) Proteins (56) HIGH ENERGY PHOSPHATES (57) 24 8  High Energy Phosphates Adenosine triphosphate mechanism, formation and utilization 25 The Critical Role of ATP ❑ the energy currency of the cell ▪ a “universal energy donor” ❑ cellular work is accomplished by proteins ▪ example of endergonic - exergonic coupling ❑ proteins that couple ATP to work are called ATPases ▪ harness energy released by hydrolysis of ATP ❑ the main ATPases in muscle: ▪ Myosin (40-50%) details in ▪ SERCA (40-50%) muscle section ▪ Na/K (10%) Figure 3.10 26 Adenosine Triphosphate ❑ 3 phosphates connected to adenosine backbone ▪ terminal phosphate connected by HIGH ENERGY BOND “hydrolyzing” this bond releases “free energy” – this free energy powers biological work ATP ATP → ADP + Pi + ADP Pi 27 9  ATP Hydrolysis Animated 28 Model of ATP as Universal Energy Donor (Fig 3.11) coupled 29 Quick REVIEW: ATP and ATPase ❑ Adenosine triphosphate (ATP) adenine, ribose, and three linked phosphates ❑ Adenosine diphosphate (ADP) adenine, ribose, and two linked phosphates ❑ ATP Hydrolysis by ATPases: ▪ ATP → → → ADP + Pi + energy (out) (exergonic) ▪ myosin ATPase ❑ ATP Synthesis by metabolic pathways: ▪ ADP + Pi + energy (in) → → → ATP (endergonic) ▪ glycolysis 30 10  Take Home Points: Bioenergetics 1 ❑ Bioenergetics ▪ process of converting food energy to a more usable form ▪ carbohydrates, fats and proteins to ATP ❑ Metabolism is an endless series of coupled reactions ▪ Endergonic: energy using ▪ Exergonic: energy releasing ❑ Oxidation-Reduction reactions are KEY to metabolism ▪ NADH / FADH are vital reducing equivalents ▪ H+ carriers (electrons) ❑ Enzymes facilitate reactions to make metabolism possible ▪ require homeostatic range for optimal performance ❑ ATP is the “universal energy donor” ▪ food energy stored in high energy bonds ▪ metabolism is phosphate driven ▪ endless cascade of making & breaking phosphate bonds 31 11