2. Bioenergetics

3. Components of a typical cell

4. Cellular Structures Cell membrane –semi-permeable –encloses internal components of cell –regulates flux of metabolites and nutrients Nucleus –contains genetic material (DNA) –regulates protein production Cytoplasm –fluid portion of the cell which contains organelles, enzymes etc.

5. Mitochondria “power station” for the cell All “aerobic” respiration takes place within the mitochondria “anaerobic” glycolysis occurs in the cytoplasm

6. ATP Generation The purpose of glycolysis and aerobic respiration is to produce ATP All of the systems we study in Exercise Physiology relate to ATP production

7. ADP and ATP structures

8. ATP as universal energy donor that drives energy needs of cells

9. Breakdown of glucose to CO 2 + H 2 O via cellular oxidation releases energy (Big Picture)

10. The First Step

11. Glycolysis: part 1

12. glycolysis: part 2

13. Glycolysis Yields Potential and Direct Energy The glycolytic process yields NADH from NAD + –NADH transported into mitochondria to produce ATP in electron transport Glycolysis also yields ATP directly by “substrate level phosphorylation”

14. Substrate Level Phosphorylation

15. Production of Lactate

16. Why Produce Lactate?

17. Fate of Glucose (Glycolysis) glucose is broken down to pyruvate pyruvate can then enter the Krebs Cycle (aerobic) or pyruvate can form lactate (lactic acid) –anaerobic, feel the burn

18. The Krebs Cycle

19. pyruvate enters the Krebs from glycolysis fatty acids also enter the Krebs cycle together pyruvate and fatty acids drive the Krebs to produce a lot of ATP

20. Krebs in Detail

21. Electrons enter respiratory chain from glycolysis and Krebs

22. Electron transport

23. Electron transport 1

24. Electron transport 2

25. Chemiosmotic theory of aerobic ATP production

26. Movement of protons across membrane and electrons along ETC Animation of Electron transport in Mitochondria.htmAnimation of Electron transport in Mitochondria.htm

27. A high proton gradient enables ATP to be generated

28. Movement of protons through ATPase generates ATP Animation of ATP synthesis in Mitochondria.htmAnimation of ATP synthesis in Mitochondria.htm

29. ATP tally from breakdown of 1 glucose molecule

30. Putting it together Glycolysis occurs in the cytosol Glycolysis feeds the Krebs cycle Krebs occurs in the mitochondria

31. Pathways of Catabolism

32. Energy Transformation Exergonic vs. endergonic rxns –exergonic produces energy –endergonic requires energy input Coupled rxns –by coupling exergonic rxn, energy can run endergonic rxn

33. Coupling exergonic and endergonic reactions

35. The energy systems Anaerobic vs aerobic systems Anaerobic (non-oxidative) –ATP-PC (Phosphocreatine or phosphagen) PC + ADP => ATP + C –Glycolysis breakdown of glucose to form 2 pyruvate or lactate Aerobic –Krebs Cycle (TCA or oxidative phosphorylation)

37. The Phosphocreatine (PC) System

38. Phosphogen Reactions PCr + ADP + H + ATP + Cr Creatine Kinase ADP + ADP ATP + AMP Adenylate Kinase

39. Phosphagen System as Bioenergetic Regulator Phosphagen system produces ATP at high rate to maintain energy state

40. Enzymes –necessary for almost all biological processes –lower Energy of Activation –work in a “lock and key” type of mechanism –very sensitive to temperature and pH remember body temp regulated in narrow range

41. Enzymes catalyze reactions by lowering energy of activation

42. Lock and Key model of enzyme action

43. Take Home Message enzymes catalyze reactions by bringing the reactants into close proximity this means less energy is required to activate the reaction

44. Fuels for Exercise Carbohydrates Fats Proteins

45. Carbohydrates-”A quick fix” Simple sugars –glucose, fructose, sucrose, maltose Complex carbs (polysaccharides) –starch, cellulose, glycogen –storage form of glucose is glycogen Glycogenolysis –process by which glycogen is broken down into glucose for use by the body

47. Fats-”Energy for the long haul” More efficient storage form of energy than CHO (9 kcal/gram vs 4 kcal/gram) Kinds of fats –fatty acids, triglycerides, phospholipids, steroids Fatty acids and triglycerides are used for energy Phospholipids and steroids are used for structural and regulatory purposes

48. Proteins-”The building blocks” Composed of sub-units called amino acids Primarily used for structural purposes (muscle tissue, tendons, ligaments) Also serve as enzymes Can be used for energy (4 kcal/gram), but not readily

49. Metabolism of Proteins, Carbohydrates and Fats