1. Energy Conversions Photosynthesis Cellular Respiration

3. Energy Conversion Energy: The ability to do work or cause motion –Potential E: “Stored Energy”; Energy of position –Kinetic Energy: Energy of motion –Chemical Energy: Potential Kinetic

6. Exothermic Vs Endothermic Exothermic: Gives off heat –Examples: Fire Endothermic: Absorbs heat –Examples: Cold Pack, Photosynthesis

7. Photosynthesis Light Reaction Light-Dependent Reactions Calvin Cycle Light-Dependent Reactions Calvin Cycle

8. Fig. 10-2 (a) Plants (c) Unicellular protist 10 µm 1.5 µm 40 µm (d) Cyanobacteria (e) Purple sulfur bacteria (b) Multicellular alga Photosynthesis: –in plants –algae, –Some protists –some prokaryotes BioFlix: Photosynthesis BioFlix: Photosynthesis

9. Structures of Photosynthesis Chloroplasts are structurally similar to photosynthetic bacteria Leaves are the main area of Photosynthesis Their green color is from chlorophyll, the green pigment CO 2 enters and O 2 exits the leaf through pores called stomata

10. Fig. 10-3a 5 µm Mesophyll cell Stomata CO 2 O2O2 Chloroplast Mesophyll Vein Leaf cross section Chloroplasts are found in cells of the mesophyll, the interior tissue of the leaf –A typical mesophyll cell has 30–40 chloroplasts Thylakoid Grana Stroma

11. Component of a Chloroplast Thylakoid – –Saclike photosynthetic membranes –Light-dependent reactions occur here Granum / Grana:– –Stack of thylakoids Stroma – –Region outside the thylakoid membrane –Reactions of the Calvin Cycle occur here

12. The Photosynthesis Equation 6 CO 2 + 6 H 2 O (light energy)  C 6 H 12 O 6 + 6 O 2 (water given off also)

13. Light- dependent reactions –Occurs in Thylakoid –Used H 2 O and light to produce ATP, NADPH, and O 2 –NADPH is an electron carrier Calvin cycle –Occurs in stroma – uses carbon dioxide, ATP, and NADPH to produce sugars

14. Photosynthesis Goal? – What is it? Needs Energy: –Photophosphorylation – –The production of ATP using energy from an electron transport chain.

15. Photosynthesis The light reactions: –(in the thylakoids): –Split H 2 O –Release O 2 –Reduce NADP + to NADPH –Generate ATP from ADP by photophosphorylation The Calvin cycle –(in the stroma) forms sugar from CO 2, using ATP and NADPH –The Calvin cycle begins with carbon fixation, CO 2 into organic molecules Photosynthesis: –Light reactions (the photo part) –Calvin cycle (the synthesis part)

16. Light Fig. 10-5-1 H2OH2O Chloroplast Light Reactions NADP + P ADP i +

17. Light Fig. 10-5-2 H2OH2O Chloroplast Light Reactions NADP + P ADP i + ATP NADPH O2O2

18. Light Fig. 10-5-3 H2OH2O Chloroplast Light Reactions NADP + P ADP i + ATP NADPH O2O2 Calvin Cycle CO 2

19. Light Fig. 10-5-4 H2OH2O Chloroplast Light Reactions NADP + P ADP i + ATP NADPH O2O2 Calvin Cycle CO 2 [CH 2 O] (sugar)

20. The light reactions convert solar energy to the chemical energy of ATP and NADPH Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 10-7 Reflected light Absorbed light Light Chloroplast Transmitted light Granum Chloroplasts are solar- powered chemical factories –Their thylakoids transform light energy into chemical energy: ATP NADPH

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27. BIOFLIX: Photosynthesis PEARSON: http://media.pearsoncmg.com/bc/bc_0med ia_bio/bioflix/bioflix.htm?9apphotosynthesi s http://media.pearsoncmg.com/bc/bc_0med ia_bio/bioflix/bioflix.htm?9apphotosynthesi s

29. Sunlight Light is a form of electromagnetic energy The electromagnetic spectrum is the entire range of electromagnetic energy, or radiation Visible light consists of wavelengths (including those that drive photosynthesis) that produce colors we can see Wavelength is the distance between crests of waves Wavelength determines the type of electromagnetic energy

30. UV Fig. 10-6 Visible light Infrared Micro- waves Radio waves X-rays Gamma rays 10 3 m 1 m (10 9 nm) 10 6 nm 10 3 nm 1 nm 10 –3 nm 10 –5 nm 380 450 500 550 600 650 700 750 nm Longer wavelength Lower energyHigher energy Shorter wavelength

31. Light and Pigments Pigments – light absorbing chemicals Chlorophyll –Chlorophyll a –Chlorophyll b –Carotenoids –Xanthophyll

32. Why do leaves change colors? Chlorophyll a Chlorophyll b

34. NADP + + e - + Energy  NADPH NADP+ –(Nicotinamide adenine dinucleotide phosphate) –Electron, hydrogen, and energy carrier

35. Light-Dependant Reactions

36. 1. Photosystem II Chlorophyll absorbs light Electrons on a chlorophyll molecule (p680) absorb energy (become excited) are “energized” High-energy electrons are passed on to the electron transport chain Chlorophyll’s electrons are replenished by the breakdown of H 2 O

37. 2. Electron Transport Chain The molecules of the electron transports chain use high-energy electrons to push H+ ions from the stroma into the inner thylakoid space.

38. 3. Photosystem I Chlorophyll absorbs light-energy and re- energized the electrons from photosystem II. NADP+ picks up these high-energy electrons and H+ to become NADPH.

40. 4. Hydrogen Ions Chemiosmosis = Electrochemical Gradient Hydrogen ions build up inside the thylakoid membrane. –High concentration of H+ inside the membrane (Strong Positive Charge) –Low concentration of H+ outside the membrane (Negative Charge) –Provides the energy to form ATP

41. 5. ATP formation H+ try to reach equilibrium. Pass through the ATP synthase Movement of H+ ions through the ATP synthase powers ATP production

42. Calvin Cycle

43. The Calvin Cycle / Dark Reaction 1.6 CO 2 molecules enter the cycle. 2.Enzyme “rubisco” (RuBP) forms 3- carbon molecules 3.ATP and NADPH form the High energy 3-Carbon molecules (G3P) 4.2 (G3P)are combined to form a 6-carbon sugar

44. Calvin Cycle

45. Factors Affecting Photosynthesis Water supply Amount of sunlight Temperature

46. LAB: Plant Pigments

49. Types of Photosynthesis C3 Photosynthesis C4 Photosynthesis CAM Photosynthesis

50. C3 Plants (Most Plants) Called C3 because the CO2 is first incorporated into a 3-carbon compound. Stomata are open during the day. Photosynthesis takes place throughout the leaf. Adaptive Value: more efficient than C4 and CAM plants under cool and moist conditions and under normal light because requires less machinery (fewer enzymes and no specialized anatomy)

51. C4 plants Called C4 because the CO 2 is first joined to make a 4C compound. Stomata are open during the day Adaptive Value: –Photosynthesizes faster than C3 plants –Can take HEAT and intense sunlight –Better water use enzymes brings in CO2 faster and so does not need to keep stomata open as much (less water lost by transpiration) for the same amount of photosynthesis. –Examples: four-wing saltbush, corn, and many of our summer annual plants.

52. CAM Plants: CAM stands for Crassulacean Acid Metabolism Stomata open at night (when evaporation rates are usually lower) During the day, the acid is broken down and the CO 2 is released to RUBISCO for photosynthesis Adaptive Value: –Better Water Use Efficiency than C3 plants under dry conditions due to opening stomata at night when transpiration rates are lower (no sunlight, lower temperatures, lower wind speeds, etc.). Examples: CAM plants include many succulents such as cactuses and agaves and also some orchids and bromeliadscactuses

54. Cellular Respiration

55. Transforming the “potential” energy in food into chemical energy cells can use: ATP CR = same way in plants and animals. Overall Reaction: –C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O

56. Cellular Respiration Overview Breakdown of glucose starts in the cytoplasm: At this point life diverges into two forms and two pathways –Anaerobic respiration = fermentation –Aerobic cellular respiration = High amounts of ATP

57. C.R. Reactions Glycolysis –Glucose molecule broken down into two 3- carbon molecules called pyruvate –Process is ancient / all organisms from simple bacteria to humans perform it the same way –Yields 2 ATP molecules for every one glucose molecule broken down –Yields 2 NADH per glucose molecule

59. Anaerobic Cellular Respiration Some organisms thrive in environments with little or no oxygen –Marshes, bogs, gut of animals, sewage treatment ponds No oxygen used = anaerobic Results in no extra ATP –ONLY to regenerate NAD+ so it can return to pick up more electrons and hydrogens End products: Alcohol or Lactic Acid: –YEAST & PLANTS: Ethanol and CO 2 in beer/bread –MUSCLE CELLS: Lactic Acid

61. Aerobic Cellular Respiration Oxygen required = aerobic 2 more sets of reactions which occur in a specialized structure within the cell called the mitochondria –1. Kreb’s Cycle –2. Electron Transport Chain

62. Kreb’s Cycle Completes the breakdown of glucose –Pyruvate 3-C broken down, the carbon and oxygen atoms end up in CO 2 and H 2 O –Hydrogens and electrons are stripped and loaded onto NAD + and FAD to produce NADH and FADH 2 Production of only 2 more ATP but loads up the coenzymes with H + and electrons which move to the 3 rd stage

64. Electron Transport Chain Electron carriers loaded with electrons and protons from the Kreb’s cycle move to this chain-like a series of steps (staircase). As electrons drop down stairs, energy released to form a total of 32 ATP Oxygen waits at bottom of staircase, picks up electrons and protons and in doing so becomes water

68. Energy Tally 36 ATP for aerobic –vs. 2 ATP for anaerobic –Glycolysis 2 ATP –Kreb’s 2 ATP –Electron Transport32 ATP 36 ATP Anaerobic organisms can’t be too energetic but are important for global recycling of carbon

71. http://ideastream.pbslearningmedia.org/re source/tdc02.sci.life.cell.mitochondria/the- powerhouse-of-the-cell/ (5:53)http://ideastream.pbslearningmedia.org/re source/tdc02.sci.life.cell.mitochondria/the- powerhouse-of-the-cell/

73. Cellular Respiration Song http://www.youtube.com/watch?v=3aZrkdz rd04http://www.youtube.com/watch?v=3aZrkdz rd04

74. Review – Compare / Contrast Photosynthesis & Cellular Respiration

75. Comparing Photosynthesis & Respiration PhotosynthesisCellular Respiration Function Energy StorageEnergy Release LocationChloroplastsMitochondria ReactantsCO 2 and H 2 OC 6 H 12 O 6 and O 2 ProductsC 6 H 12 O 6 and O 2 CO 2 and H 2 O Equation 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O

81. Redox Reactions A chemical reaction involving the transfer of one or more elections from one reactant to another; also called oxidation/reduction reactions In oxidation, a substance loses electrons, or is oxidized In reduction, a substance gains electrons, or is reduced (the amount of positive charge is reduced)

82. Fig. 9-UN1 becomes oxidized (loses electron) becomes reduced (gains electron)

83. Fig. 9-UN2 becomes oxidized becomes reduced

84. Reverse Process of Each Other Oxidative phosphorylation O2 reduced to H2O using electrons donated by NADH or FADH2 (Respiration) Photophosphorylation just the reverse, H2O oxidized to O2 with electrons accepted (Photosynthesis)

85. The Light-Dependent Reactions Photophosphorylation is the process of creating ATP using a Proton gradient created by the Energy gathered from sunlight. Chemiosmosis is the process of using Proton movement to join ADP and P.

86. What is the function of NADPH? How is light energy converted into chemical energy during photosynthesis? Can the complete process of photosynthesis take place in the dark? Explain your answer.