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PHOTOSYNTHESIS

PHOTOSYNTHESIS. CAPTURING ENERGY Chapter 6. ENERGY . Autotrophs – Organisms that make their own food from inorganic substances and energy (ATP). Use photosynthesis – converting light energy into chemical energy Store chemical energy as organic compounds (like carbohydrates)

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PHOTOSYNTHESIS

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  1. PHOTOSYNTHESIS CAPTURING ENERGY Chapter 6

  2. ENERGY • Autotrophs – Organisms that make their own food from inorganic substances and energy (ATP). • Use photosynthesis – converting light energy into chemical energy • Store chemical energy as organic compounds (like carbohydrates) • EX: plants, algae, and some bacteria

  3. PHOTOSYNTHESIS6CO2+6H2O+light C6H12O6+6O2 • A biochemical pathway that involves a complex series of chemical reactions • The product of this reaction is consumed in the next reaction • Process supports virtually all life on Earth

  4. Understanding Photosynthesis • 1. Jan Van Helmont (1600’s) – set up an experiment to understand how a small seed grew to a large tree • Concluded that plants need water to grow. • 2. Joseph Priestly (1771) – set up an experiment with a candle…he discovered a candle in a jar died out but a candle in a jar with a plant continued burning. • 3. Jan Ingenhousz (1779)– found that the plant/candle experiment only worked when the plant was exposed to sunlight • Concluded: light is necessary for plants to produce oxygen

  5. The Nature of Light • Visible Spectrum – the separation of white light into different colors (wavelengths) • PIGMENT – a molecule that absorbs certain wavelengths of light and reflects or transmits others

  6. Chloroplasts- organelle that contains chlorophyll and other pigments; site of photosynthesis • Contains: • Thylakoids – disk-shaped structures that contain photosynthetic pigments • Grana – Stacks of thylakoids (resemble stacks of pancakes) • Stroma – Solution surrounding the thylakoids • Chlorophyll- light collecting pigment located on the thylakoid disks

  7. CHLOROPHYLL and PIGMENTS • The most common and important photosynthetic pigments in plants and algae. • Absorbs violet, blue, and red lights. • Reflect and Transmit Green light – giving plants their GREEN color. • Chlorophyll a – primary photosynthetic pigment • Accessory Pigments – Chlorophyll b and carotenoids

  8. LIGHT REACTIONS • Initial reactions of photosynthesis • Begins with absorption of light in chloroplasts (in the thylakoids) to create chemical energy (ATP and NADPH)

  9. Light rxn. • Water molecules are split, creating electrons, protons, and oxygen as a byproduct animation

  10. Light rxn. Cont. • Reactants: H2O + Sunlight • Products: O2 + ATP + NADPH (energy carrier) + H+ (used later)

  11. Chemiosmosis • The synthesis of ATP • Occurs when there is a concentration gradient of protons across the thylakoid membrane • ADP  ATP

  12. CALVIN CYCLE • Second set of reactions in photosynthesis • Is not dependent on light • Occurs in the stroma (liquid area of the chloroplast) when ATP and NADPH are present • Makes stored energy (in the form of carbs) that the plant can use

  13. How is this done? • Carbon fixation: carbon atoms are bonded (“fixed”) into organic compounds • aided by enzymes • Reactants: CO2 + ATP + NADPH + H+ • Products: O2 + C6H12O6

  14. Animation

  15. The rate of photosynthesis varies: • 1. light intensity • 2. amount of CO2 • 3. temperature

  16. Notebook quiz • Write the equation for photosynthesis out in words? • Where in the chloroplast do the light reactions occur? • What are the products of the light reaction? • What are the products of the Calvin Cycle? • What is the primary photosynthetic pigment in plants?

  17. ALTERNATIVE PATHWAYS STOMATA – small pores in leaves of plants • C4 Plants – close stomata during hot parts of the day (still able to produce carbohydrates) • EX: corn, sugar cane, crabgrass • CAM Plants – open stomata at night and close them during the day…producing organic compounds at night • EX: cactus, pineapples

  18. CELLULAR RESPIRATION MAKING ENERGY animation

  19. CELLULAR RESPIRATION • C6H12O6 + 6O2 6CO2+6H2O+ energy(ATP) • The complex process in which cells make ATP by breaking down organic compounds • Heterotrophs – Organisms that obtain energy from eating autotrophs or other heterotrophs

  20. GLYCOLYSIS • The beginning of cellular respiration • Glucose is converted into 2 molecules of pyruvic acid • Produces very little ATP and NADH glucose pyruvic acid

  21. GLYCOLYSIS PRODUCTION • Glycolysis USES 2 ATP molecules to start the pathway • Glycolysis MAKES 4 ATP molecules at the end of glycolysis • Therefore, glycolysis produces: • Net total of 2 ATP • NADH • 2 molecules of Pyruvic Acid

  22. WithOxygen…glycolysis is followed by AEROBIC RESPIRATION to produce more ATP • Examples of aerobic exercise: long distance activities • WithoutOxygen…glycolysis is followed by FERMENTATION (anaerobic respiration) producing no ATP • Examples of anaerobic exercise: sprinting

  23. FERMENTATION • Without Oxygen…Glycolysis goes to Anaerobic Respiration • Does not produce ATP • Recycles NAD+ from NADPH to keep glycolysis going • 2 most common fermentation pathways: • LACTIC ACID FERMENTATION • ETHYL ALCOHOL FERMENTATION

  24. LACTIC ACID FERMENTATION • Converts pyruvic acid into lactic acid • Helps produce some foods ex) yogurts and cheeses • Also occurs in your muscle cells during very strenuous exercise ex) sprinting • As lactic acid accumulates…it reduces the ability of the muscle cells to contract…resulting in fatigue, pain, and cramping

  25. ALCOHOLIC FERMENTATION • Used by some plant cells and unicellular organisms • Converts pyruvic acid into ethyl alcohol • Used in the wine and beer industries and in the making of breads

  26. AEROBIC RESPIRATION • Occurs when Oxygen is present in the cell • Pyruvic acid is converted to CO2 and water • Produces large amounts of ATP • Takes place in the mitochondria • 2 major stages: The Kreb’s Cycle Electron Transport Chain

  27. THE PRODUCTION OF ATP

  28. THE KREB’S CYCLE • Occurs in the mitochondrial MATRIX (space inside the inner membrane of the mitochondria) • Biochemical pathway that breaks down acetyl CoA, and produces CO2, hydrogen atoms, and ATP • 1 Glucose molecule gives 2 cycles of the Kreb’s cycle and produces: • 6 NADH • 2 FADH2 • 2 ATP • 4 CO2

  29. ELECTRON TRANSPORT CHAIN • Second stage of aerobic respiration…occurs along the many folds (cristae) of the mitochondria • 4 NADH from Glycolysis produce a total of 12 ATP • 6 NADH from Kreb’s produce a total of 18 ATP • 2 FADH2 from Kreb’s produce a total of 4 ATP • Electron Transport Chain Produces a TOTAL of 34 ATP

  30. CELLULAR RESPIRATION • THE ENTIRE PROCESS CAN PRODUCE A TOTAL OF 38 ATP

  31. Why do leaves change color in the fall? • How do annuals and perennials survive winter? • Why do deciduous trees loose their leaves and evergreens do not loose their needles? • Why do the leaves fall from the trees in autumn? • How and why do the leaves separate from the tree? • What is anthocyanin? • Name other pigments that appear in leaves after the chlorophyll disappears. • Where is the best place to see the color change? Why?

  32. Photosynthesis Comic Directions • Create a minimum 6 slide comic strip summarizing the process of photosynthesis .Be sure to include the reactants and products of the light and dark reactions.

  33. Cellular Respiration Poster! • Design a poster summarizing all important parts of the stages of aerobic and anaerobic cellular respiration. • Show how all of the processes are related • Be creative • Be prepared to show your poster to the rest of the class and explain its contents

  34. Notebook Quiz • Distinguish between autotrophs and heterotrophs. • What are the (3) products of glycolysis? • After glycolysis, what determines the next step? • What type of fermentation occurs in animal cells? • What are the 2 steps of aerobic respiration? • How many ATP are produced in cellular respiration?

  35. Notebook Quiz • What is the primary photosynthetic pigment in plants? • In photosynthesis, where do the light reactions occur? Where does the Calvin Cycle occur? • What is the chemical energy produced in photosynthesis? • What molecule made in photosynthesis is “burned” in cellular respiration? • Distinguish between autotrophs and heterotrophs. • What are the 3 products of glycolysis? • After glycolysis, what determines the next step?

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