1. Chapter 8 An Introduction To Metabolism

2. Metabolism All the chemical reactions in an organism
Concerned with managing the matter and energy resources of the organism.

3. http://www. cc. gatech. edu/~turk/bio_sim/articles/metabolic_pathways

4. Catabolic Pathways
Pathways that break down complex molecules into smaller ones, releasing energy.
Example: Cellular Respiration

5. Anabolic Pathways
Pathways that consume energy, building complex molecules from smaller ones.
Example: Photosynthesis

6. Anabolic vs Catabolic

7. Energy Ability to do work.
The ability to rearrange a collection of matter.
Forms of energy:
Kinetic
Potential
Activation

8. Kinetic Energy
Energy of action or motion.

9. Potential Energy
Stored energy
Can be in chemical bonds!

10. Activation Energy
Energy needed to convert potential energy into kinetic energy.
Activation Energy
Potential Energy

12. Energy Transformation
Governed by the Laws of Thermodynamics.

13. 1st Law of Thermodynamics
Energy can be transferred and transformed, but it CANNOT be created or destroyed.
Also known as the law of “Conservation of Energy”

14. 2nd Law of Thermodynamics
Each energy transfer or transformation increases the entropy of the universe.

15. Entropy
Measure of disorder.
High entropy = high disorder

16. Free Energy Changes

17. Question? How does Life go against Entropy?
By using energy from the environment or external sources (e.g. food, light).

18. Summary
The quantity of energy in the universe is constant, but its quality is not.

19. Gibbs Free Energy
Free energy = The portion of a system's energy that can perform work.
“usable energy”

20. Free Energy of a reaction
ΔG = ΔH – TΔS Δ = Change (final – initial) G = free energy of a system H = enthalpy = total energy of a system T = temperature in oK S = entropy of a system

21. Reactions will move from unstable states to stable states

22. Free Energy Changes

23. Reaction Types
Exergonic: chemical reactions with a net release of free energy.
ΔG = NEGATIVE VALUE
Spontaneous
catabolic
Endergonic: chemical reactions that require free energy from the surroundings.
ΔG = POSITIVE VALUE
Anabolic

26. Biological Examples Exergonic - respiration
Endergonic - photosynthesis

27. How does the cell perform endergonic reactions?
Couples an exergonic process to drive an endergonic one.
ATP is used to couple the reactions together.

28. ATP Adenosine Triphosphate Made of: - Adenine (nitrogenous base)
- Ribose (pentose sugar)
- 3 phosphate groups

30. Adenine
Phosphates
Ribose

31. Key to ATP Is in the three phosphate groups.
Negative charges repel each other and makes the phosphates unstable.

32. ATP
Works by energizing other molecules by transferring phosphate groups.

33. ATP vs Food ATP: Food: Renewable energy resource. Unstable bonds
Long term energy storage
Stable bonds

35. ATP Cycles Energy released from ATP drives endergonic reactions.
Energy from exergonic reactions “recharges” ATP.

36. ATP in Cells A cell's ATP content is recycled every minute.
Humans use close to their body weight in ATP daily.
No ATP production equals quick death.

37. Enzymes Biological catalysts made of protein.
Cause the rate of a chemical reaction to increase.

38. Enzymes
Lower the activation energy for a chemical reaction to take place.

39. free energy

40. Enzyme Terms Substrate - the material and enzyme works on.
Enzyme names: Ex. Sucrase
- ase name of an enzyme
1st part tells what the substrate is. (Sucrose)

41. Control of Metabolism Is necessary if life is to function.
Controlled by switching enzyme activity "off" or "on” or separating the enzymes in time or space.

43. Structural Order
Separation of enzymes and metabolic pathways in time or space by the cell's organization.
Example: enzymes of respiration

45. Summary Recognize that Life must follow the Laws of Thermodynamics.
The role of ATP in cell energy.
How enzymes work.

46. Cellular Respiration and Photosynthesis
You will need to know the inputs and outputs of each reaction
Where is each reaction taking place
Understand what the “goal” of each reaction is
What is the role of the major molecules
Connect back to previous material (facilitated diffusion, active transport, exergonic, endergonic)

47. Rs - Equation
C6H12O6 + 6 O2 6 CO2 + 6 H2O + ATP The energy is released from the chemical bonds in the complex organic molecules.

48. Oxidation - definitions
Loss of electrons.
Loss of energy.

49. Reduction - definitions
Gain of electrons.
Gain of energy.

58. Photosynthesis Equation
6 CO2 + 6 H2O + Sunlight C6H12O6 + 6 O2

60. Fig. 5.3

61. Fig. 5.4

65. Cellular Respiration Animations Glycolysis http://www. science. smith
Cellular Respiration Animations Glycolysis Krebs Cycle Electron Transport Chain

66. Photosynthesis Animations Light Dependent Reactions Calvin Cycle