Energy and the Cell

1. Energy and the Cell

2. What do you know… • About energy? • Is it matter? • What kinds are there? • Can it be transformed to other forms?

3. What is energy? • “Capacity to do work” • Do living organisms need energy? • YES!!!!!!!!!

4. Contrast

5. Explain potential and kinetic energy of the roller coaster

6. Kinetic Actually doing work (moving) Potential Stored energy Due to location or arrange- ment (of atoms) Two Types of Energy 0-C-0

7. Kinetic Pedaling a bike Heat = moves molecules electron jumps (go to Bohr’s quantum behavior of an atom) Examples ICE STEAM

8. Potential Energy • Potential • Water behind a dam • Electron’s position in an atom

9. Name the type:

10. What’s the most important type to living organisms? • Chemical • The energy in food molecules can be stored in the bonds

11. Explain the energy transfers:

12. When you break bonds… • You release the energy that held the bonds together • This energy can do work in the body.

13. Thermodynamics • laws governing energy transfer

14. First Law of thermodynamics • in closed system, energy can neither be created nor destroyed, only changed in form.

15. First Law of Thermodynamics Examples • Light energy to chemical energy (from sun to sugar in a plant) • Water behind a dam (potential) is released (kinetic)

16. How does this explain energy transfers?

17. What energy transfers are occurring?

18. Second Law of Thermodynamics • energy transformations inevitably involve increased disorder or entropy. • NOTE: it is the environment that is increasing disorder, not the cell

19. Entropy…what is that? • Living things use this energy to create order (reduce entropy) locally, but the overall entropy of the solar system invariably increases.

20. In other words… • If a particular systembecomes more ordered, its surrounding become more disordered • A cell makes organelles to increase order, but its surroundings become less orderly

21. Second Law • energy of all kinds in our material world disperses or dissipates if it is not hindered from doing so

22. Must be spontaneous • All spontaneous happenings in the material worldare examples of the second law because they involve energy dispersing.

23. Could you explain that in other words? • heat flows from hot(more energy) to cold (less energy) • diffusion leads to substances becoming uniformly dispersed

24. You could think of cells as • “Islands of Low Entropy”

25. Is the transformation perfect? • A cell cannot transfer or transform energy with 100% efficiency. • Where does the lost energy go? • Mostly lost as heat.

26. NOT Just organizing your desk

27. Do Worksheet • Hot pans of water • Water on Niagara • Air in tires that got a puncture • Speeding car hits a brick wall • Spark in contact with gasoline • Sun’s energy hits the ocean • Huge earthquake under the ocean

28. Exergonic Reaction • Releases Energy • Begins with reactants whose covalent bonds contain more energy than its products

29. Burning One big step Breaking bonds Many smaller steps Exergonic: Releasing Energy

30. Exergonic Example • Glucose (reactant) breaks down into carbon dioxide and water(products) • C6H12O6 CO2 + H2O

31. “Cellular Respiration” • Breaking glucose molecules to release energy and store it in a form the cell can use (ATP molecules) • “slow burn”

32. Endergonic Reaction • The products have more energy than the reactants • Requires an inputof energy • Usually in the form of ATP

33. Endergonic Reaction • Carbon dioxide and water combine to form glucose CO2 + H2O C6H12O6

34. “Cellular Metabolism” • Sum of exergonic and endergonic reactions of cells • CO2 + H2O C6H12O6 • Less energy more energy molecules molecules

35. ATP • No…not the new rock band from Japan • Well, what is it?

36. ATP • Adenosine Triphosphate • “cell’s batteries” • “energy currency”

37. ATP

38. How are they different? • Adenosine triphosphate • Adenosine diphosphate

39. Third Phosphate • Acts as an energy shuttle

40. Making ADP + Pi • ATP is energy rich and breaks down into ADP and Pi (inorganic phosphate) + energy • is exergonic

41. Making ATP • energy + ADP + Pi -> ATP is endergonic • requiring the input of energy.

42. Which has more energy? • ATP or ADP? • Answer: ATP

43. Phosphorylation • Adding of a phosphate group to a molecule

44. Energy Coupling • Energy released from exergonic reactions drive endergonic reactions ADP + Pi <=> ATP +

45. REACTIONS • The end products of a reaction may have more (endergonic) or less (exergonic) energy than the substrate molecules.

46. REACTIONS • Most reactions are reversible, occur in both directions - • reactants -> end products • AND end products -> reactants.

47. REACTIONS • Reversible reactions move toward an equilibrium, a state in which the reaction occurs at about the same rate in both directions.

48. So... • ATP is like money in a checking account

49. Adenosine triphosphate (ATP) P P P + P P P Adenosine diphosphate (ADP) Hydrolysis of ATP • ATP + H2OADP + P(exergonic) Hydrolysis (add water)

50. Adenosine triphosphate (ATP) P P P + P P P Adenosine diphosphate (ADP) Dehydration of ATP • ADP + PATP + H2O(endergonic) Dehydration synthesis (remove water)