Lecture 2 Outline (Ch. 8, 9)

2. Lecture 2 Outline (Ch. 8, 9) • Energy • Thermodynamics • Metabolism and Chemical Reactions • V. Cellular Energy - ATP • Enzymes & Regulation • Cell Respiration • Redox Reactions • Glycolysis • Coenzyme Junction • VII. Preparation for next Lecture

3. Energy What is Energy? Where does energy on earth come from originally? [equivalent of 40 million billion calories per second!] Types of Energy: - Kinetic Energy = energy of movement - Potential = stored energy

4. Energy Potential Energy Kinetic Energy Thermodynamics – study of energy transformation in a system Potential energy can be converted to kinetic energy (& vice versa)

5. Thermodynamics Laws of Thermodynamics: Explain the characteristics of energy • 1st Law: • Energy is conserved • Energy is not created or destroyed • Energy can be converted (Chemical  Heat) 2nd Law: • During conversions, amount of useful energy decreases • No process is 100% efficient • Entropy (measure of disorder) is increased Energy is converted from moreordered to less ordered forms

6. Potential vs. Kinetic Energy

7. Metabolism and Energy Cells convert molecules chemically using cellular energy.

8. Metabolism Metabolism – chemical conversions in an organism Metabolic reactions: All chemical reactions in organism • Anabolic = builds up molecules Catabolic = breaks down molecules Two Types of Metabolic Reactions

9. Chemical Reactions + + Reactants Products • Chemical Reaction: • Process that makes and breaks chemical bonds • Two Types of Chemical Reactions: • 1) Exergonic = releases energy • 2) Endergonic = requires energy

10. Metabolism • Metabolic reactions: • Chemical reactions in organism Two Types of Metabolic Reactions: • Anabolic = build up Catabolic = break down Exergonic = release energy Endergonic = requires energy

11. Chemical Reactions Glucose  CO2 + H20 CO2 + H20 Glucose -ΔG +ΔG (or 0) release energy intake energy spontaneous non-spontaneous • Exergonic reaction • Endergonic reaction

12. Question/Recall: Which has more order? Stores more energy? Polymer or Monomer, Diffused or Concentrated H+? What is relationship between order and energy?

13. What type of energy is stored in a covalent bond? A. Kinetic energy B. Diffused energy C. Heat energy D. Potential energy E. Conventional energy

14. Cellular Energy - ATP • ATP = adenosine triphosphate • ribose, adenine, 3 phosphates • last (terminal) phosphate - removable Be able to diagram ATP! 

15. ATP + H2O ADP + Pi Cellular Energy - ATP • ATP hydrolyzed to ADP • Exergonic • Energy released, used in another reactions (endergonic)

16. Cellular Energy - ATP • ATP regenerated • cells power ATP generation by coupling to exergonic reactions Like cellular respiration!

17. ATP Cycle

18. Making ATP from ADP + Pi is… • Exergonic because it releases energy • Endergonic because it requires energy • Exergonic because it requires energy • Endergonic because it releases energy

19. Chemical Reactions • Chemical Reactions: • Like home offices – tend toward disorder • Endergonic – energy taken in; Exergonic – energy given off Exergonic Endergonic

20. Self-Check

21. Chemical Reactions Nucleus Nucleus Repel Activation Energy Activation Energy Nucleus Nucleus Repel Activation Energy: Energy required to “jumpstart” a chemical reaction • Must overcome repulsion of molecules due to negative • charged electrons

22. Chemical Reactions • Exergonic Reaction: • Reactants have more energy than products Activation energy: Make sugar and O2 molecules collide sugar + O2 water + CO2 “Downhill” reaction

23. Respiration (ch. 9) preview Cellular Respiration Equation: C6H12O6 + O2 CO2 + H2O You will need to KNOW this equation.

24. Chemical Reactions and Enzymes Enzymes • lower activation energy only for specific reactions • cell chooses which reactions proceed! enzymes: cannot make rxns go that wouldn’t otherwise Cannot change endergonic into exergonic rxns Dospeed up rxns that would occur anyway

25. Enzymes • Enzymes – control rate of chemical reaction • sucrase – enzyme sucrose breakdown “-ase” enzyme • sucrase – catalyst -speed up rxn, but not consumed

26. Enzymes • enzyme – specific to substrate • active site – part of enzyme -substrate • binding tightens fit – induced fit • form enzyme-substrate complex • catalytic part of enzyme: converts reactant(s) to product(s)

27. Enzymes • Enzymes lowers EA by: -template orientation -stress bonds • substrate(s) enter -microenvironment • enzyme reused • product(s) formed • What factors might affect enzyme activity?

28. Enzymes • inhibitors: binds & blocks active site binds allosteric site – alters conformation • Drug – blocks HIV enzyme at the active site

29. If a competitive inhibitor is in an enzyme reaction, can you reverse the inhibition by adding more substrate? • Yes • No • I’m not sure • Wait, what’s a competitive inhibitor?

31. Cellular Respiration Overall purpose: • convert food to energy • animals AND plants • complementary to photosynthesis

32. Cellular Respiration: (Exergonic) Cellular Respiration • catabolizes sugars to CO2 • requires O2 • at mitochondrion

33. Redox Reactions • as part of chemical reaction, e- are transferred • e- transfer = basis of REDOX reactions (reduction) (oxidation)

34. Redox Reactions Use “H rule” for reactions in this class Reactant with more H’s = e donor, will be oxidized Reactant with more O’s = e acceptor, will be reduced ZH2 + O2 yields ZO + H2O • follow the H, e- move with them

35. Self-Check Oxygen ZH2

36. Redox Reactions Equation for respiration

37. Redox Reactions • transfer of e- to oxygen is stepwise

38. • glucose NADH ETC O2 (makes H2O) Redox Reactions • e- moved by NAD/H (from niacin/vit B3) • NADH  carry e- (reduced!) • NAD+  not carrying e- (oxidized!) Where do e- come from? Where do e- go?

39. In this equation is NAD+ to NADH oxidized or reduced? NAD+ + H+ + 2e-  NADH • Reduced, it gained electrons • Oxidized, it gained electrons • Reduced, it lost electrons • Oxidized, it lost electrons

40. Steps of Respiration • Steps of respiration: 1. glycolysis 2 CO2 Coenzyme Junction 2. Citric acid cycle 4 CO2 3. ETC 4. Chemiosmosis

41. Cellular Respiration • Stages of respiration: 1. Glycolysis – prep carbons

42. Cellular Respiration 1. Glycolysis • 1 glucose (6C) 2 pyruvate (3C) • Keep track of: - inputs - ATP - NAD+/NADH - CO2 and H2O - outputs • eukaryotes AND prokaryotes

43. Glucose Glucose-6-phosphate ATP 2 1 ADP Fructose-6-phosphate Glucose-6-phosphate Glycolysis

44. ATP Fructose- 1, 6-bisphosphate ADP 4 5 Glyceraldehyde- 3-phosphate Dihydroxyacetone phosphate Glycolysis

45. 2 ADP 2 ATP Phosphoenolpyruvate 2 2 ADP 10 2 ATP Pyruvate 2 Glycolysis Step not shown

46. How many NET ATP are produced by glycolysis? • one • two • four • six • eight

47. Cellular Respiration Glycolysis -inputs: 1 Glucose 2 ATP -outputs: 2 pyruvate 4 ATP (2 net) 2 NADH CO2 = none yet (2 H2O) Where do the outputs go?

48. Energy production Mitochondria • energy from nutrients  ATP

49. Cellular Respiration Coenzyme Junction • 2 pyruvate (3C) 2 Acetyl CoA (2C) • pyruvate joins coenzyme A (from vitamin B5) • 2 carbons lost (as CO2) • 2 NAD+  NADH

50. Things To Do After Lecture 2… • Reading and Preparation: • Re-read today’s lecture, highlight all vocabulary you do not understand, and look up terms. • Ch. 8 Self-Quiz: #1-6 (correct answers in back of book) • Read chapter 9, focus on material covered in lecture (terms, concepts, and figures!) • Skim next lecture. • “HOMEWORK” (NOT COLLECTED – but things to think about for studying): • Describe the relationship between exergonic/endergonic, catabolic/anabolic, and “uphill”/”downhill” chemical reactions • Diagram one molecule of ATP and how ADP is different • Cut apart the boxes on the previous sheet – match up three (name, energy balance, basic reaction) for glycolysis and three for the coenzyme junction • Place the following molecules in order for when they are used/created during glycolysis: fructose-6-phosphate, glucose, glucose-6-phosphate, pyruvate, glyceraldehyde-3-phosphate