1. Gibbs Free E & ATP

2. Thermodynamics: the laws of energy transformations.

3. The First Law of Thermodynamics
According to the first law of thermodynamics:
Energy cannot be created or destroyed
Energy can be transferred and transformed

4. Energy The capacity to cause change or do work Various forms of energy
Kinetic (motion)
Heat (thermal) from random movement of atoms
Potential (location/structure)
Can be converted, but never created/destroyed

5. Organisms need energy for…
Synthesis of molecules
Reproduction
Movement
Active transport
Temperature regulation

6. Chemical Energy is stored in the structure of molecules within the bonds between atoms.
Energy can be added or released by changing the arrangement of electrons (rearranging chemical bonds).

7. WHY does a chemical bond form
WHY does a chemical bond form? Explain in terms of stability of electrons.
A bond forms when the valence electrons of 2+ atoms interact. The share or transfer electrons makes each more stable.

8. Think of a chemical bond like 2 magnets sticking together- the positive pole of one sticks to the negative pole of another. If you move them close, they will stick automatically (no energy needed to make them do so). Once the magnets are joined, it WOULD require energy to separate them.

9. Using the analogy… does making bonds release or require energy. Why
Using the analogy… does making bonds release or require energy? Why? Relate to the stability of atoms.

10. Using the analogy… does breaking bonds release or require energy. Why
Using the analogy… does breaking bonds release or require energy? Why? Relate to the stability of atoms.

11. The Second Law of Thermodynamics: every energy transfer or transformation increases the entropy, or disorder, of the universe. S

12. Explain how this is an example of increasing entropy: A log being burned.
A log is an organized collection of molecules. As it is burned it becomes ash and gases in the air which are much less organized.

13. Explain how this is an example of increasing entropy: Liquid water is heated until all evaporates as a gas.
As a liquid becomes a gas the molecules separate from each other and become less organized

14. Explain how this is an example of increasing entropy: Sugar being broken down in cells to release energy to do work (cellular respiration). C6H12O6 + 6O2 → 6CO2 + 6H2O
Glucose is a highly organized molecule and is broken down into smaller more stable molecules

15. Give two examples of chemical reactions or processes that living organisms undergo that decreases the entropy of their cells or bodies.
Growing, building a muscle or bone, making new cells, repairing cells or organs, concentrating substances in one part of the cell

16. The natural direction of change is always towards more entropy
The natural direction of change is always towards more entropy. How is it that organisms are able to become more organized? Are they defying the laws of the universe? Explain.
Organisms use energy to overcome the entropy and organize themselves
As they become more organized the entropy of their surroundings increases (mainly heat).

17. Gibbs Free Energy (G) “Available energy”
Energy that can do work under cellular conditions
Concept from Thermodynamics

18. Metabolism is the totality of an organism’s chemical reactions.

19. Ex: Cell respiration (breaking down glucose)
Catabolic pathways break down complex molecules into simpler compounds.
Ex: Cell respiration (breaking down glucose)

20. Ex: Photosynthesis (using sunlight to synthesize glucose)
Anabolic pathways build complicated molecules from simpler ones and consume energy.
Ex: Photosynthesis (using sunlight to synthesize glucose)

21. An organism’s metabolism transforms matter and energy, subject to the laws of thermodynamics.

22. Increased disorder and entropy are offset by biological processes that maintain or increase order.

23. Organisms use free energy to maintain organization, grow and reproduce.

24. Energy input must exceed energy lost to entropy to maintain order and power cellular processes.

25. Any excess free energy acquired by an organism that is not used for maintenance or reproduction is either stored or used for growth.

26. Loss of order, flow of energy, or insufficient acquired free energy results in loss of mass and, ultimately, the death of an organism.

27. ΔG=ΔH - TΔS ΔG = available (free) energy in a system
ΔH= enthalpy, or total energy available
T= temperature in Kelvin (K) K = C
ΔS=entropy, or the amount of disorder in the system

28. Exergonic reactions:
Net release of energy
Spontaneous
(-ΔG)

29. Spontaneous ( G < 0) and release energy: exergonic.
Exergonic Reactions

30. Endergonic reactions: absorb free energy from surroundings.
Nonspontaneous.
(+ΔG)

31. Nonspontaneous ( G > 0) and consume energy: endergonic.
Endergonic Reactions

34. Order is maintained by coupling cellular processes that increase entropy with those that decrease entropy. (Using exergonic reactions to power endergonic reactions)

37. Example of a coupled reaction: ATP→ADP Used to maintain or increase order by being coupled with reactions that have a positive free energy change.
Reaction: ATPADP
*Releases energy (exergonic)
*Energy converted to heat
BUT…if we couple this reaction…
*Protein needs to change shape (endergonic)
Energy from ATP hydrolysis (exergonic) used to change the shape of a protein (endergonic)
We are increasing order (entropy).

38. Most energy coupling in cells is mediated by ATP.

39. Phosphorylation: transferring a phosphate group to another molecule.
This is how ATP drives endergonic reactions.

40. Can’t store ATP. Too reactive Only for short-term energy storage
Carbs & fats for long term
So….need to recycle ATP

41. ADP/ATP Cycle

42. Make sure you are always in the same unit!
Calculating Gibbs
Gibbs – kJ, cal, kcal, or J
Enthalpy- kJ, cal, kcal, or J
Entropy – J/K or kJ/K or cal/K or kcal/K
Make sure you are always in the same unit!
Temperature is in Kelvin (K)
Standard temperature is 298K (25oC)

43. Calculating Gibbs You have a reaction that looks like this: A+B  AB.
The change in enthalpy is +12kJ. The change in entropy is -5 J/K. *NOTE! Unit differences…
Calculate the amount free energy.
Is it endergonic or exergonic?
Is it spontaneous or not?
ΔG=ΔH – TΔS

44. Calculating Gibbs
You have a reaction that looks like this: CD  C + D.
The change in enthalpy is -32 cal. The change in entropy is +25 cal/K.
Calculate the amount free energy.
Is it endergonic or exergonic? Is it spontaneous or not?