1. CELLULAR ENERGY
Unit 4
Chapter 8

2. ORGANISMS OBTAIN ENERGY
All living organisms use energy to carry out all biological processes

3. TRANSFORMATION OF ENERGY
All processes require energy

4. ENERGY
The ability to do work

5. THERMODYNAMICS
Study
The flow of energy
The transformation of energy

6. LAWS OF THERMODYNAMICS
I. Law of conservation
Energy can be converted, one form to another
Energy cannot be created nor destroyed
II. Law of entropy
Energy cannot be converted without the loss of usable energy (thermal energy)

7. ENERGY All organisms need Begins with the sun
Directly from the sun or indirectly

8. AUTOTROPHS Convert light energy to food Make their own food
Photoautotrophs
Chemoautotrophs

9. HETEROTROPHS
Organisms that need to ingest food to obtain energy

10. METABOLISM
All the chemical reactions in a cell

11. METABOLIC PATHWAY A series of chemical reactions
The product of one becomes the substrate for the next
Catabolic – releases energy (big molecules to small)
Anabolic – uses catabolic energy (small to big)
Continual flow of energy in an organism from catabolic to anabolic pathways

12. PHOTOSYNTHESIS Anabolic pathway Light from sun
Converted to chemical energy
Use by the cell

13. PHOTOSYNTHESIS Plant (autotrophs)
Use light energy, carbon dioxide and water
Produce glucose and oxygen

14. CELLULAR RESPIRATION Catabolic pathway
Organic molecules are broken down
Energy is released
Cell uses the energy

15. CELLULAR RESPIRATION Oxygen is used to break down organic molecules
Produces carbon dioxide and water

16. ATP THE UNIT OF CELLULAR ENERGY
Adenosine triphosphate
Most important biological molecule
Provides chemical energy

17. ATP STRUCTURE Most abundant energy-carrier molecule in cells
Found in all types of organisms

18. ATP FUNCTION
Releases energy when the bond between the 2nd and 3rd is broken

19. ATP ADP CYCLE

21. 8.2

22. PHOTOSYNTHESIS
Light energy

23. PHOTOSYNTHESIS
Light energy
Trapped

24. PHOTOSYNTHESIS
Light energy
Trapped
Converted into chemical energy

25. PHOTOSYNTHESIS
6CO2 + 6H2O C6H12O6+ 6O2

26. PHOTOSYNTHESIS Two steps I. Light-dependent reaction
II. Light-independent reaction

27. PHASE ONE: LIGHT REACTION
The absorption of light
Two energy storage molecules
NADPH and ATP
Are produced

28. CHLOROPLAST Large organelle Cells of leaves
Thylakoid – flattened disc arranged in grana
Stroma – fluid-filled space outside the grana

29. PIGMENT Light absorbing colored molecules
In the thylakoid membranes of chloroplasts
Different ability to absorb specific wavelengths of light
Most common
Chlorophyll a and chlorophyll b
Absorb violet-blue
Reflect green

30. CAROTENOIDS
Carrots and sweet potatoes
Absorb blue and green

31. ELECTRON TRANSPORT Structure of the thylakoid Large surface area
Holds electron transporting molecules
Two types of photosystems (protein complexes)

32. 1. ELECTRON TRANSPORT Light energy excites electrons in photosystem II
Also causes a water molecule to split
Releases
an electron into the ET system
A hydrogen ion (H+) into thylakoid space
Oxygen as a waste product

33. 1. ELECTRON TRANSPORT Light energy excites electrons in photosystem II
Also causes a water molecule to split
Releases
an electron into the ET system
A hydrogen ion (H+) into thylakoid space
Oxygen as a waste product

34. 2. ELECTRON TRANSPORT
The excited electrons move from photosystem II to an electron-acceptor molecule in the thylakoid membrane

35. 3. ELECTRON TRANSPORT
The electron-acceptor molecule transfers the electrons along a series of electron-carriers to photosystem I

36. 4. ELECTRON TRANSPORT In the presence of light
Photosystem I transfers electrons to ferrodoxin
Lost electrons by photosystem I are replaced by electrons from photosystem II

37. 5. ELECTRON TRANSPORT
Ferrodoxin transfers the electrons to the electron carrier NADP+
Forms the energy-storage molecule NADPH

38. PHASE TWO: THE CALVIN CYCLE
NADPH and ATP not stable to store energy for a long time
Calvin Cycle is where energy is stored in organic molecules (glucose)

39. 1. CALVIN CYCLE Carbon fixation, 6 CO2 combine with 5-carbon compounds
Form 12 3-carbon molecules (3-phosphoglycerate)
3-PGA

40. 2. CALVIN CYCLE ATP and NADPH energy Transferred to 3-PGA molecules
Form G3P high energy molecules glyceraldehyde
ATP – supplies the phosphate groups
NADPH – supplies the H+ and e-

41. 3. CALVIN CYCLE 2 G3P molecules leave the cycle
Used for production of glucose and other organic compounds

42. 4. CALVIN CYCLE
Rubisco (enzyme) converts G3P to 5-carbon molecules called ribulose 1, 5-bisphosphates
These combine with new CO2 to continue cycle

43. ALTERNATIVE PATHWAYS Environments low in water or carbon dioxide
Maximize energy conversion

44. C4 PLANTS Maintain photosynthesis minimizing water loss
Sugar cane and corn
Fix CO2 into four-carbon compounds
Significant structural modifications, leaves
Stomata close during hot days

45. CAM PLANTS Crassulacean acid metabolism
Water conserving plants in the desert
Cacti, orchids and pineapple
Water limited environments
Allow CO2 to enter only at night, release it during the day

47. CELLULAR RESPIRATION
Unit 4
Chapter 8.3

48. CELLULAR RESPIRATION
Living organisms obtain energy by breaking down organic molecules during cellular respiration

49. FUNCTION Harvest electrons from carbon compounds
And use the energy to produce ATP

50. CELLULAR RESPIRATION I. Glycolysis – anaerobic process
II. Krebs cycle – aerobic respiration
Anaerobic – without oxygen
Aerobic – oxygen

51. GLYCOLYSIS
Cytoplasm
One molecule of glucose
Makes 2 ATP and 2 NADH

52. GLYCOLYSIS 2 phosphate groups join glucose
6-carbon molecule is broken down to two 3-carbon compounds
Two phosphates, e- and H+ are added = NADH
Two 3 carbon compounds converted into two molecules of pyruvate AND four molecules of ATP

53. TWO ATP & TWO PYRUVATE

54. KREBS CYCLE Pyruvate is transported into the mitochondrial matrix
Converted to CO2
TCA – tricarboxylic acid

55. KREBS CYCLE Acetyl CoA combines with 4-carbon = 6-carbon (citric acid)
Citric acid broken down to 5-carbon compound
Carbon dioxide breaks off and forms a 4-carbon compound
Two pyruvate formed from glycolysis
Two turns of the Krebs cycle
Each turn = 6CO2, 2ATP, 8NADH and 2FADH2

56. ELECTRON TRANSPORT Final step in breaking glucose ATP is produced
Electrons move along the mitochondrial membrane from one protein to another
End result protons and electrons transferred to oxygen to form water

57. ELECTRON TRANSPORT
24 ATP

58. ANAEROBIC RESPIRATION
Organisms live with low oxygen
Grow & reproduce without oxygen
Fermentation – anaerobic pathway that follows gylcolysis

59. LACTIC ACID FERMENTATION
Enzymes convert pyruvate to lactic acid
Muscles become fatigued and feel sore due to lactic acid.

60. ALCOHOL FERMENTATION Yeast and some bacteria
Pyruvate converts to ethyl alcohol and CO2