1. Cell Energetics  Honors Photosynthesis and Cellular Respiration (Chapters 8 & 9)

2. Cell energy Necessary for life  must be able to produce, store, and use energy ATP  chemical energy

3. ATP  adenosine triphosphate ADP + P i  ATP Bond of 3 rd phosphate is tenuous Renewable Unlimited supply of energy in presence of P i

4. When bond breaks, energy is released

5. Cells use energy to: Obtain and transform nutrients Transport materials Eliminate wastes Maintenance of homeostasis

6. Photosynthesis Process by which light energy is converted into chemical energy

7. Factors involved in photosynthesis Light  energy form consisting of a combination of different wavelengths ROYGBIV  visible (white) light

8. Factors cont. Water  provides H + and O 2 (by- product) Atmospheric O 2 comes from here CO 2  amount directly affects the rate of photosynthesis

9. Factors cont. Chlorophyll  pigments that absorb certain wavelengths of light A and b  absorb blue-violet and red light Green is never absorbed  reflected back

10. Light dependent reactions  daytime only Also called photolysis Provides energy to run the next set of reactions

11. H 2 O is split into H and O 2H 2 O  4H + + 4e- + O 2 (released as a gas) H + transferred to hydrogen carriers 2NADP + + 2H +  2NADPH (energy storage) 4e- used to make ATP

12. Light-independent reactions  day and night Also called the Calvin Cycle or the carbon fixation cycle CO 2 is split C is added to RuBP (5-C sugar) to form two 3-C molecules CO 2 + RuBP  2PGA

13. Light-independent cont. ATP and NADPH convert PGA to another 3-C molecule PGA + ATP + NADPH  PGAL ADP and NADP + return to light dep. Reactions 2 molecules of PGAL are used to make glucose

14. Light-independent cont. Some PGAL molecules and ATP reform RuBP  back to beginning Any excess glucose is stored as starch

15. Calvin Cycle

17. Photosynthesis Overview

18. Chemical equation for photosynthesis 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2

19. Stomates allow for gas exchange

20. Cellular respiration Process by which cells release energy (mitochondria)

21. Chemical equation 6O 2 + C 6 H 12 O 6  6CO 2 + 6H 2 O Opposite of photosynthesis

22. 2 types of respiration Aerobic  uses O 2 Anaerobic  no O 2 Both start with the same reaction  glycolysis

23. Glycolysis  Step 1 Glucose is split

24. Involves oxidation-reduction reactions (redox) Oxidation  e- are lost (or H atoms) Reduction  e- are gained (or H atoms) O 2 is the final e- acceptor  H 2 O Energy is released during each transfer

25. First part: C 6 H 12 O 6 + 2ATP  2PGAL + 2ADP + P i Energy is added to break C-H bonds

26. Second part: 2PGAL  2 pyruvic acid + 4ATP 2NADH and 2H + are also formed Pyruvic acid moves into mitochondrion

28. Net energy gain 4ATP  end product - 2ATP  put into reaction 2ATP  net gain Not very efficient

29. Aerobic respiration

30. Step 2  intermediate reaction Pyruvic acid is oxidized Pyruvic acid + coenzyme A  acetyl- CoA CO 2 is released, NADH and H + are formed

31. Step 3  the citric acid cycle (the Krebs cycle) Each molecule of acetyl-CoA takes a turn 1 acetyl-CoA = 1 ATP produced 1 glucose = 2 acetyl-CoA 2 ATP are released and various energy carriers

32. Krebs Cycle

34. Step 4  the electron transport chain Energy carriers move down the chain  releases energy gradually (32 ATP)

36. Net energy yield 2ATP  glycolysis + 2ATP  Krebs cycle +32ATP  e- transport chain 36ATP  grand total

37. Cell Respiration Overview

38. Anaerobic respiration Fermentation

39. Pyruvic acid is converted to: Lactic acid  human muscle cells Ethanol (ethyl alcohol)  yeast Both produces still contain most of the chemical energy of glucose Release of 4 ATP

40. Anaerobic overview

41. Net energy yield 2ATP  glycolysis + 0ATP  anaerobic reactions 2ATP  grand total Much less efficient than aerobic

42. Comparing photosynthesis to respiration PhotosynthesisCellular Respiration Food is producedFood is broken down Energy from the sun is stored in glucose Energy of glucose is released as ATP CO 2 taken in, O 2 given off O 2 taken in, CO 2 given off Occurs only with chlorophyll Occurs in all living cells