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. Do living organisms need energy? YES!!!!!!!!!
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. 0-C-0 Two Types of Energy Potential Stored energy Kinetic
Due to location or arrange-
ment (of atoms)
Kinetic
Actually doing work (moving)
0-C-0

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

8. Potential Potential Energy 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. You release the energy that held the bonds together
When you break bonds…
You release the energy that held the bonds together
This energy can do work in the body.

13. laws governing energy transfer
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 system becomes 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 world are 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. Exergonic: Releasing Energy
Breaking bonds
Many smaller steps
Burning
One big step

30. Exergonic Example
Glucose (reactant) breaks down into carbon dioxide and water (products)
C6H12O 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 input of energy
Usually in the form of ATP

33. CO2 + H2O C6H12O6 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. Adenosine Triphosphate “cell’s batteries” “energy currency”
ATP
Adenosine Triphosphate
“cell’s batteries”
“energy currency”

37. ATP

38. Adenosine triphosphate Adenosine diphosphate
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. energy + ADP + Pi -> ATP is endergonic
Making ATP
energy + ADP + Pi -> ATP is endergonic
requiring the input of energy.

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

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

44. Energy released from exergonic reactions drive endergonic reactions
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. ATP is like money in a checking account
So...
ATP is like money in a checking account

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

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

51. ATP
Breaks down readily
Would break down spontaneously except for the energy barrier

52. If entropy is spontaneous…
Why aren’t we all just spontaneously combusting?

53. Energy of Activation EA
The amount of energy that reactants must absorb to start a chemical reaction

54. But what if…
The barrier is too great and the reaction cannot go…
Use ENZYMES

55. “Biological Catalysts”
Enzymes
“Biological Catalysts”
(speed up a reaction without being changed themselves)

57. Usually named for what they work on EXAMPLE: Lipase works on Lipids
Enzymes
Usually end in –ase
Usually named for what they work on
EXAMPLE: Lipase works on Lipids

58. How do enzymes work?
Each enzyme has a specific shape, which will determine which reactants it will work on

59. Substrate=A substance that the enzyme acts on
Active Site- small area where enzyme and substrate work
Substrate=A substance that the enzyme acts on

60. Induced Fit
Slight change in the shape of the active site of an enzyme as it embraces its substrate (like grasping hands)
Enzyme animation

61. Is an enzyme…
Able to be used over and over?
YES!!!!!!!!!

62. Most enzymes… Work best at what temperature? 35-40oC
What happens at high temperatures?
Denatures them (unravels)
Why is salty bad?
Salt ions interfere with chemical bonds

63. Most enzymes… What is the optimal pH? 6-8
What does too low (too acidic) of pH do to enzymes?
Extra H+ ions interfere with chemical bonds

64. Cofactores Nonprotein helpers EXAMPLES: Zn, Fe, Cu (inorganic ones)
Vitamins like B6 (organic ones)=also called coenzymes

65. Enzyme Inhibition Competetive inhibitor
Resembles the enzyme and competes for the active site
Noncompetetive inhibitor
Does not enter the activ site
Binds somewhere outside the active site
Inhibitor animations

66. When a cell’s supply exceeds the demand Negative Feedback animation