1 / 67

Chapter 8 Metabolism & Enzymes

Chapter 8 Metabolism & Enzymes. METABOLISM ENERGY AND LIFE. What is life?. Life is a collection of chemical reactions. LIFE IS WORK. Cells need energy to do work. Figure 6.1  The complexity of metabolism. METABOLIC PATHWAY. -series of steps -enzyme directed

emerson-nieves
Download Presentation

Chapter 8 Metabolism & Enzymes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 8 Metabolism & Enzymes

  2. METABOLISM ENERGY AND LIFE

  3. What is life? Life is a collection of chemical reactions.

  4. LIFE IS WORK

  5. Cells need energy to do work

  6. Figure 6.1  The complexity of metabolism

  7. METABOLIC PATHWAY -series of steps -enzyme directed -enzyme managed -the management of material and energy resources Catabolic Anabolic

  8. Metabolism • forming bonds between molecules • dehydration synthesis • anabolic reactions • breaking bonds between molecules • hydrolysis • catabolic reactions

  9. CATBOLIC RELEASES ENERGY COUPLED RXN’s USES/STORES ENERGY ANABOLIC

  10. Transformations! Potential to Kinetic

  11. THERMODYNAMICS the study of energy transformations Closed system? Open? (Bioenergetics)

  12. 1st LAW OF THERMODYNAMICS: Energy can be changed but not created or destroyed Energy of universe is constant A qualitative change - not quantitative

  13. 2ND LAW OF THERMO.: Entropy of the universe is constantly increasing

  14. Which of these happens spontaneously?

  15. DEFINE ENTROPY- randomness or disorder WHAT CAUSES IT?- energy transfers or transformations

  16. WHAT IS FREE ENERGY? energy available for work WHAT IS WORK? any change!

  17. Order as a characteristic of life

  18. Potential Energy Kinetic Energy

  19. Organisms require energy to live • Sources of energy? Coupling exergonic reactions (releasing energy) with endergonic reactions (needing energy) energy + + energy + +

  20. 1st + 2nd = Quantity of energy is conserved but not the quality Fate of all energy is to end up as heat energy - not available for work

  21. Organisms are open systems that exchange energy and materials with their surroundings. They create ordered structures using energy that flows into environment as light. They take in ordered structures and create less ordered ones and release heat. Living systems then increase entropy. Complex organisms developed from simpler ones. Entropy?

  22. REACTIONS! SPONTANEOUS OR NOT? With or without outside help?

  23. Kinetic and potential energy: dam

  24. The relationship of free energy to stability, work capacity, and spontaneous change

  25. Disequilibrium and work in closed and open systems

  26. When a spontaneous process occurs in a system, stability of the system is increased. Unstable systems tend to change to become more stable.

  27. More free energyLess stableGreater work capacity • In a spontaneous change • free energy decreases (ΔG<0) • system becomes more stable • released free energy can be used to do work More free energyLess stableGreater work capacity

  28. Energy changes in exergonic and endergonic reactions

  29. EXERGONIC REACTIONS: • ENERGY RELEASING REACTIONS • PROCEEDS WITH A NET LOSS OF FREE ENERGY • DOWNHILL; SPONTANEOUS • NEGATIVE FREE ENERGY

  30. ENDERGONIC REACTIONS- • ENERGY REQUIRING • PROCEEDS WITH A NET GAIN OF FREE ENERGY • UPHILL; NONSPONTANEOUS • POSITIVE FREE ENERGY

  31. G = free energy H = total energy S = entropy T = ‘C + 273 = K G = H - TS

  32. G = H - T S G = free energy G = Gfinal state - Ginitial state H = total energy (enthalpy) T = degrees Kelvin S = entropy

  33. Disequilibrium and work in closed and open systems

  34. Spontaneous?? Systems that are- High free energy &/or low entropy Unstable Highly ordered

  35. In a spontaneous process, free energy decreases G < 0

  36. Nature runs downhill! To occur spontaneously, the system must either give up energy (a decrease in H), give up order (an increase in S) or both. G < 0

  37. END PART 1

  38. ATP

  39. The structure and hydrolysis of ATP

  40. ATP

  41. Energy coupling by phosphate transfer

More Related