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MONDAY BELLRINGER

MONDAY BELLRINGER. GET OUT YOUR COMPOSITION NOTEBOOK TURN TO YOUR FIRST BLANK PAGE TITLE IT PHOTOSYNTHESIS . Make sure you are in the proper seat in order to be counted present!!. History of Photosynthesis & Plant Pigments. Investigating Photosynthesis.

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MONDAY BELLRINGER

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  1. MONDAY BELLRINGER GET OUT YOUR COMPOSITION NOTEBOOK TURN TO YOUR FIRST BLANK PAGE TITLE IT PHOTOSYNTHESIS. Make sure you are in the proper seat in order to be counted present!!

  2. History of Photosynthesis & Plant Pigments

  3. Investigating Photosynthesis • Many Scientists Have Contributed To Understanding Photosynthesis • Early Research Focused On The Overall Process • Later Researchers Investigated The Detailed Chemical Pathways

  4. Van Helmont’s Experiment 1643 • Planted a seed into A pre-measured amount of soil and watered for 5 years • Weighed Plant & Soil. Plant Was 75 kg, Soil The Same. • Concluded Mass Came From Water

  5. Priestley’s Experiment 1771 • Burned Candle In Bell Jar Until It Went Out. • Placed Sprig Of Mint In Bell Jar For A Few Days. • Candle Could Be Relit And Burn. • Concluded Plants Released Substance (O2) Necessary For burning.

  6. Ingenhousz’s Experiment 1779 Repeated Priestly experiment with & without sunlight

  7. Results of Ingenhousz’s Experiment • Showed That Priestley’s Results Only Occurred In The Presence Of Sunlight. • Light Was Necessary For Plants To Produce The “Burning Gas” or oxygen

  8. Julius Robert Mayer 1845 Proposed That Plants can Convert Light Energy Into Chemical Energy

  9. Samuel Ruben & Martin Kamen1941 Used Isotopes To Determine That The Oxygen Liberated In Photosynthesis Comes From Water RUBIN KAMEN

  10. Melvin Calvin 1948 • First to trace the path that carbon (CO2) takes in forming Glucose • Does NOT require sunlight • Called the Calvin Cycle or Light Independent Reaction • Also knownas the Dark Reaction

  11. Rudolph Marcus 1992 • Studied the Light Independent Reactions • First to describe the Electron transport Chain

  12. The Photosynthesis Equation

  13. Pigments • In addition to water, carbon dioxide, and light energy, photosynthesis requires Pigments • Chlorophyll is the primary light-absorbing pigment in autotrophs • Chlorophyll is found inside chloroplasts

  14. Light and Pigments • Energy From The Sun Enters Earth’s Biosphere As Photons • Photon = Light Energy Unit • Light Contains A Mixture Of Wavelengths • Different Wavelengths Have Different Colors

  15. Light & Pigments • Different pigments absorb different wavelengths of light • Photons of light “excite” electrons in the plant’s pigments • Excited electrons carry the absorbed energy • Excited electrons move to HIGHER energy levels

  16. Chlorophyll There are 2 main types of chlorophyll molecules: Chlorophyll a Chlorophyll b A third type, chlorophyll c, is found in dinoflagellates Magnesium atom at the center of chlorophyll

  17. Chlorophyll a and b

  18. Chlorophyll a • Found in all plants, algae, & cyanobacteria • Makes photosynthesis possible • Participates directly in the Light Reactions • Can accept energy from chlorophyll b

  19. Chlorophyll b • Chlorophyll b is an accessory pigment • Chlorophyll b acts indirectly in photosynthesis by transferring the light it absorbs to chlorophyll a • Like chlorophyll a, it absorbs red & blue light and REFLECTS GREEN

  20. What then is Photosyntehsis?

  21. What is Photosynthesis ? • Involves the use of light Energy to convert Water (H20) and Carbon Dioxide (CO2) into Oxygen (O2) and High Energy Carbohydrates (sugars, e.g. Glucose) & Starches

  22. Photosynthesis Overview • AUTOTROPHS • Plants and some other types of organisms that contain chlorophyll are able to use light energy from the sun to produce food. Make their own food using the sunlight

  23. Photosynthesis Overview • HETEROTROPHS • Are organisms that can NOT make their own food • They can NOT directly use the sun’s energy

  24. Photosynthesis Overview • Energy • Energy takes many forms such as light, heat, electrical, chemical and mechanical • Energy can be stored in chemical bonds and then released later on

  25. Photosynthesis Overview Cells Use BIOCHEMICAL energy Cells use ATP for: • Active transport • Movement • Photosynthesis • Protein Synthesis • Cellular respiration • All other cellular reactions

  26. Photosynthesis Overview • ATP – Cellular Energy • Adenosine Triphosphate • Contains two, high-energy phosphate bonds • Also contains the nitrogen base adenineand a ribose sugar

  27. Photosynthesis Overview • ADP – Adenosine Diphosphate • ATP releases energy, a free phosphate, & ADP when cells take energy from ATP

  28. Importance of ATP Principal Compound Used To Store Energy In Living Organisms

  29. Importance of Atp • ATP is constantly being used and remade by cells • ATP provides all of the energy for cell activities • The high energy phosphate bonds can be BROKEN to release energy • The process of releasing ATP’s energy & reforming the molecule is called phosphorylation

  30. Releasing Energy from Atp Lose • Adding A Phosphate Group To ADP stores Energy in ATP • Removing A Phosphate Group From ATP Releases Energy & forms ADP Gain

  31. One more thing on ATP • Cells Have Enough ATP To Last For A Few Seconds • ATP must constantly be made • ATP Transfers Energy Very Well • ATP Is NOT Good At Energy Storage

  32. Photosynthesis Overview

  33. The Biochemical Reactions

  34. It Begins with Sunlight!

  35. Photoautotrophs Absorb Light Energy

  36. Inside A Chloroplast

  37. Structure of the Chloroplast • Double membrane organelle • Outer membrane smooth • Inner membrane forms stacks of connected sacs called thylakoids • Thylakoid stack is called the granum (grana-plural) • Gel-like material around grana called stroma

  38. Function of the Stroma • Light Independent reactions occur here • ATP used to make carbohydrates like glucose • Location of the Calvin Cycle

  39. Thylakoid membranes • Light Dependent reactions occur here • Photosystems are made up of clusters of chlorophyll molecules • Photosystems are embedded in the thylakoid membranes • The two photosystems are: • Photosystem I • Photosystem II

  40. Photosynthesis Overview

  41. Energy Carriers • Nicotinamide Adenine Dinucleotide Phosphate (NADP+) • NADP+ = Reduced Form • Picks Up 2 high-energy electrons and H+ from the Light Reaction to form NADPH • NADPH carries energy to be passed on to another molecule

  42. NADPH

  43. Light Dependent Reactions • Occurs across the thylakoid membranes • Uses light energy • Produce Oxygen from water • Convert ADP to ATP • Also convert NADP+ into the energy carrier NADPH

  44. Light Dependent Reaction

  45. Light Dependent Reaction

  46. Photosystem I • Discovered First • Active in the final stage of the Light Dependent Reaction • Made of 300 molecules of Chlorophyll • Almost completely chlorophyll a

  47. Photosystem I High-energy electrons are moved to Photosystem I through the Electron Transport Chain Energy is used to transport H+ from stroma to inner thylakoid membrane NADP+ converted to NADPH when it picks up 2 electrons & H+

  48. Photosystem II • Discovered Second • Active in the beginning stage Of the Light Dependent Reaction • Contains about equal amounts of chlorophyll a and chlorophyll b

  49. Photosystem II absorbs light energy Electrons are energized and passed to the Electron Transport Chain Lost electrons are replaced from the splitting of water into 2H+, free electrons, and Oxygen 2 H+ pumped across thylakoid membrane Photosynthesis Begins

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