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Photosynthesis

Photosynthesis. Chapter 8 photosynthesis rap . Energy and Life. 8-1. Types of Nutrition. Autotrophs – make their own food. Heterotrophs – consume their food. Energy. Forms of energy: Light, heat, sound, electrical, chemical… The form of energy used by living things is chemical .

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Photosynthesis

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  1. Photosynthesis Chapter 8 photosynthesis rap

  2. Energy and Life 8-1

  3. Types of Nutrition Autotrophs – make their own food Heterotrophs – consume their food

  4. Energy • Forms of energy: • Light, heat, sound, electrical, chemical… • The form of energy used by living things is chemical. • The principal chemical compound that stores and releases energy in cells is ATP • Adenosine triphosphate

  5. ATP ATP Section 8-1 Adenine Ribose 3 Phosphate groups

  6. ATP • ATP stores energy in the bonds between the phosphates. • To store energy, ADP adds on a third phosphate to become ATP. • To release energy, ATP gives up the third phosphate to become ADP

  7. Figure 8-3 Comparison of ADP and ATP to a Battery ATP charging Section 8-1 ADP ATP Energy Energy Adenosine triphosphate (ATP) Adenosine diphosphate (ADP) + Phosphate Partially charged battery Fully charged battery

  8. Using ATP in Cells • Active transport • Charging nerve cells • Movement • Protein synthesis • Cell division • ALL chemical reactions! • Everything!

  9. Photosynthesis: An Overview 8-2

  10. Jan van Helmont After careful measurements of a plant’s water intake and mass increase, van Helmont concluded that trees gain most of their mass from water. 1643

  11. 1771 Joseph Priestley Using a bell jar, a candle and a plant, Priestley finds that a plant releases oxygen.

  12. 1779 Jan Ingenhousz Ingenhousz finds that aquatic plants produce oxygen bubbles in the light but not in the dark. He concludes that plants need sunlight to produce oxygen.

  13. 1845 Julius Robert Mayer Mayer proposes that plants convert light energy into chemical energy.

  14. 1948 Melvin Calvin Calvin traces the chemical path that carbon follows to form glucose. These reactions are known as the Calvin Cycle.

  15. 1992 Rudolph Marcus Marcus wins the Nobel prize in chemistry for describing the process by which electrons are transferred from one molecule to another in the electron transport chain.

  16. Great Theories…. • Are they made by a single scientist? • Or are they the work of many scientists over many years?

  17. The Photosynthesis Equation • Photosynthesis uses the energy of sunlight to convert water and carbon dioxide into high-energy sugars and oxygen. Carbon dioxide + water + light  glucose + oxygen 6CO2 + 6H2O + light  C6H12O6 + 6O2

  18. Light and Pigments • Photosynthesis requires the presence of light- absorbing molecules called pigments. • Chlorophyll is the principal pigment. • This pigment is located in the chloroplasts.

  19. Photosynthesis: Reactants and Products Light Energy Chloroplast Sugars + O2 CO2 + H2O

  20. Photosynthetic Pigments • Chlorophyll a absorbs violet and red light the best. • It does NOT absorb green or yellow well. • Chlorophyll b absorbs mainly blue and red wavelengths of light. • It does NOT absorb green or yellow either. • There are two other photosynthetic pigments, carotene (orange) and xanthophyll (yellow). • They absorb other wavelengths of light and transfer the energy to chlorophyll.

  21. Photosynthetic Pigments Absorption of Light by Chlorophyll a and Chlorophyll b Chlorophyll b Chlorophyll a V B G Y O R

  22. The Reactions of Photosynthesis 8-3

  23. Photosynthesis overview

  24. Chloroplast Anatomy • Stacks of internal membranes called thylakoids contain photosystems. • Photosystems carry out the reactions of photosynthesis involving light (“light reactions”). • In between the thylakoids the stroma carries out more reactions that do not require light (“dark reactions”).

  25. CO2 Light Sugars O2 Figure 8-7 Photosynthesis: An Overview Section 8-3 H20 Chloroplast Chloroplast NADP+ ADP + P Light- Dependent Reactions Calvin Cycle ATP NADPH

  26. The Light Reactions • Takes place in the thylakoids. • Chlorophyll absorbs light. • Light energy is used to do two things: • Split water into hydrogen and oxygen gas. • Oxygen is released to the environment. • Hydrogen is carried to the stroma for the next set of reactions. • Produce high energy carriers ATP and NADPH • Both are used in the dark reactions. • http://vcell.ndsu.nodak.edu/animations/ • http://www.youtube.com/watch?feature=player_embedded&v=BK_cjd6Evcw

  27. Figure 8-10 Light-Dependent Reactions Section 8-3 Hydrogen Ion Movement Chloroplast Photosystem II ATP synthase Inner Thylakoid Space Thylakoid Membrane Stroma Electron Transport Chain Photosystem I ATP Formation

  28. The “Dark” reactions • Take place in the stroma • Don’t require light • Carbon dioxide is combined with hydrogen to make glucose. • Energy (ATP) from the light reactions runs the dark reactions. • Also known as the “Calvin Cycle” and “carbon fixation”.

  29. Figure 8-11 Calvin Cycle Section 8-3 CO2 Enters the Cycle Energy Input ChloropIast 5-Carbon Molecules Regenerated 6-Carbon Sugar Produced Sugars and other compounds

  30. Factors Affecting Photosynthesis • Availability of water • Temperature • Light intensity • Availability of minerals • Concentration of carbon dioxide

  31. Transpiration • How does water get to the leaves for photosynthesis? • “Transpiration pull” brings water up to the leaves. • Transpiration is the loss of water vapor out the leaves through openings called stomates.

  32. Transpiration Section 23-5 A B Evaporation of water molecules out of leaves. Pull of water molecules upward from the roots.

  33. Transpiration Section 23-5 A B Evaporation of water molecules out of leaves. Pull of water molecules upward from the roots.

  34. Transpiration • What regulates water loss from the leaves? • Guard cells open and close the stomates to regulate water loss. • In dry conditions guard cells close the stomates. • In wet conditions guard cells open the stomates.

  35. The Internal Structure of a Leaf Section 23-4 Cuticle Veins Epidermis Palisademesophyll Xylem Vein Phloem Spongymesophyll Epidermis Stoma Guardcells

  36. Syringa leaf cross section

  37. Function of Guard Cells Section 23-4 Guard cells Guard cells Inner cell wall Inner cell wall Stoma Stoma Open Stoma Closed

  38. Guard Cells and Stomates

  39. Essential Plant Nutrients • What else does a plant need from the soil besides water?

  40. Essential Plant Nutrients Section 23-2 Nutrient Nitrogen Phosphorus Potassium Magnesium Calcium Role in Plant Proper leaf growth and color; synthesis of amino acids, proteins, nucleic acids, and chlorophyll Synthesis of DNA; development of roots, stems, flowers, and seeds Synthesis of proteins and carbohydrates; development of roots, stems, and flowers; resistance to cold and disease Synthesis of chlorophyll Cell growth and division; cell wall structure; cellular transport; enzyme action Result of Deficiency Stunted plant growth; pale yellow leaves Poor flowering; stunted growth Weak stems and stunted roots; edges of leaves turn brown Thin stems; mottled, pale leaves Stunted growth; curled leaves

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