Chpt. 8 An Intro to Metabolism

1. Chpt. 8 An Intro to Metabolism

2. Metabolism- totality of an organism’s chemical reactions

3. Metabolism- totality of an organism’s chemical reactions molecules are altered molecules are atered molecules are ateed

4. Metabolism- molecules are altered molecules are atered molecules are ateed Enzymes catalyze each step

5. MetabolicReactions: • Types: • Catabolic- breakdown molecules • release energy • ex. cellular respiration

6. MetabolicReactions: • Types: • Anabolic- build molecules consume energy • ex. making proteins from amino acids

7. enzyme enzyme + H2O Examples • dehydration synthesis (synthesis) + H2O • hydrolysis (digestion)

8. enzyme enzyme Examples • dehydration synthesis (synthesis) • hydrolysis (digestion)

9. HOW ORGANISMS MANAGE THEIR ENERGY resources Bioenergetics

10. capacity to do work: change in the state or motion of matter energy

11. Cells obtain chemical energy when molecules are rearranged:

12. Therefore, a basic knowledge of ENERGY is necessary to understand how cells work…

13. PotentialEnergy • stored in molecules in the chem. bonds …is converted to KineticEnergy

14. PotentialEnergy - where is it in this picture?

15. KineticEnergy • (energy of motion) • energy that “powers” the cell.ex. cell respiration, releases energy stored in the bonds of sugar molecules.

16. KineticEnergy Where is it here??? This one is easy to see!

17. Thermodynamics energy transformation

19. 1stLawofThermodynamics chemical energy was not created, and will not be destroyed… but it can change forms

20. B C A

21. Flow of energy through life • Life is built on chemical reactions transforming energy from one form to another organic moleculesATP & organic molecules sun organic moleculesATP & organic molecules solar energyATP& organic molecules

23. 2ndLawofThermodynamics Every energy transfer or transformation, increases entropy (disorder) in the Universe

24. Christian Right Lobbies To Overturn Second Law Of Thermodynamics September 6, 2000 | Issue 36•31 TOPEKA, KS–The second law of thermodynamics, a fundamental scientific principle stating that entropy increases over time as organized forms decay into greater states of randomness, has come under fire from conservative Christian groups, who are demanding that the law be repealed. "What do these scientists want us teaching our children? That the universe will continue to expand until it reaches eventual heat death?" asked Christian Coalition president Ralph Reed, speaking at a rally protesting a recent Kansas Board Of Education decision upholding the law. "That's hardly an optimistic view of a world the Lord created for mankind. The American people are sending a strong message here: We don't like the implications of this law, and we will not rest until it has been reversed in the courts." The controversial law of nature, which asserts that matter continually breaks down as disorder increases and heat is lost, has long been decried by Christian fundamentalists as running counter to their religion's doctrine of Divine grace and eternal salvation. "Why can't disorder decrease over time instead of everything decaying?"

25. HEAT is a very DISORDERED form of energy 2ndLawofThermodynamics Every energy transfer or transformation increases entropy (disorder) in the Universe

26. Chemical reactions & energy digesting molecules= LESS organization=lower energy state • Some chemical reactions release energy • exergonic • breaking polymers • hydrolysis = catabolism • Some chemical reactions require input of energy • endergonic • building polymers • dehydration synthesis = anabolism building molecules= MORE organization=higher energy state

27. Living cells, unavoidable, convert organized forms of energy to heat Get it… convert to HEAT

28. Quantity of Energy is always the same Quality is not

29. remember: heat is a pretty danged - disordered form of energy! Now, THAT’s some disordered HEAT!!

30. spontaneous processes changes that occur on their own…

31. spontaneous processes • When spontaneous processes occur in a system (an organism), stabilityincreases~ but in terms of the universe, it decreases

32. Unstable systems tend to become more stable spontaneously.

33. How can we predict which changes occur spontaneously, and which require input of E. from the outside?

34. ENERGY, in a system, THAT CAN PERFORM WORK Free Energy

35. G measure of this freeenergy

36. Yale scientist featured in stamp series Gibbs received the first Ph.D. in engineering in the U.S. from Yale in 1863. He later became a member of the Yale faculty.

37.  G =  H - T  S - free energy temp*entropy change total energy = Entropy = measure of disorder

38.  G =  H - T  S - free energy amount ofuseableE.todo work total potentialenergy~ total bond energy enthalpy entropy = unuseable energy

39. Not all of the energy in a system is available for work

40. We can use this to predict which changes occur spontaneously, and which require input of E. from the outside?

41.  G =  H - T  S - free energy entropy total energy = spontaneous changes, decrease free energy

42. Unstable Systems - change spontaneously, becoming stable systems, and FreeEnergyDecreases

43. Endergonic vs. exergonic reactions exergonic endergonic - energy released - digestion • energy invested • synthesis +G -G G = change in free energy = ability to do work

45. Chemical Reactions (2 types): • Exergonic- proceeds with a net release of free E. • G is negative spontaneous • Endergonic- proceeds with a net gain of Energy/ absorbs it • G is positive nonspontaneous

46. Chemical Reactions (2 types): • Exergonic- proceeds with a net release of free E. exergonic - energy released - digestion -G

47. Chemical reactions & energy digesting molecules= LESS organization=lower energy state • Some chemical reactions release energy • exergonic • breaking polymers • hydrolysis = catabolism • Some chemical reactions require input of energy • endergonic • building polymers • dehydration synthesis = anabolism building molecules= MORE organization=higher energy state

49. Cells “work” three ways: • Mechanical work = muscle contraction • Transport work = pumping across membranes • Chemical work = making polymers ENERGY SOURCE for the work is ATP

50. Adenine Phosphates Ribose sugar