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. PHOTOSYNTHESIS 6CO 2 +6H 2 O+lightC 6 H 12 O 6 +6O 2  A biochemical pathway that involves a complex series of chemical reactions  Process supports virtually all life on Earth

4. Understanding Photosynthesis  1. Jan Van Helmont (17 th century) – 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 (100 years later) – 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 – 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 photsynthetic 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 – Chlorphyll b and carotenoids

8. LIGHT REACTIONS  Initial reactions of photosynthesis  Begins with absorption of light in chloroplasts (in the thylakoids)  Produces: NADPH (energy carrier), ATP, & H + needed in the Calvin Cycle to make FOOD

9. Light rxn. Animation

10. Light rxn. Cont.  Reactants: H 2 O + Sunlight  Products: O 2 + ATP + NADPH + 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  Produces organic compounds using energy from ATP & NADPH made in the light reactions.  Occurs in the stroma (liquid area of the chloroplast)

13. Calvin cycle cont.  Is not dependent on light!  Occurs when ATP and NADPH are present  Makes stored energy (in the form of carbs.) the plant can use

14. How is this done?  Carbon fixation: carbon atoms are bonded (“fixed”) into organic compounds  Reactants: CO 2 + ATP + NADPH + H +  Products: O 2 + C 6 H 12 O 6

15. Animation

17. The rate of photosynthesis varies:  1. light intensity  2. amount of CO 2  3. temperature

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

20. Notebook quiz 1) Write the equation for photosynthesis out in words? 2) Where in the chloroplast do the light reactions occur? 3) What are the products of the light reaction? 4) What are the products of the Calvin Cycle? 5) What is the primary photosynthetic pigment in plants?

21. CELLULAR RESPIRATION MAKING ENERGY

22. CELLULAR RESPIRATION  C 6 H 12 O 6 + 6O 2 6CO 2 +6H 2 O+ energy  The complex process in which cells make ATP by breaking down organic compounds  HETEROTROPHS – Organisms that obtain energy from eating autotrophs or other heterotrophs

23. GLYCOLYSIS  The beginning of cellular respiration  A biochemical pathway that produces very little ATP –With Oxygen…glycolysis is followed by AEROBIC RESPIRATION to produce more ATP Examples of aerobic exercise: long distance activities –Without Oxygen…glycolysis is followed by FERMENTATION (anaerobic respiration) producing no ATP Examples of anaerobic exercise: sprinting

24. GLYCOLYSIS (cont.) Organic Compounds GlycolysisATP no Oxygenwith Oxygen FermentationAerobic (anaerobicRespiration ATP

25. GLYCOLYSIS PRODUCTION  Glycolysis USES 2 ATP molecules to start the pathway  Glycolysis MAKES 4 ATP molecules at the end of glycolysis  Therefore Glycolysis: –PRODUCES A TOTAL OF 2 ATP –NADH –2 molecules of Pyruvic Acid

26. FERMENTATION  Without Oxygen…Glycolysis goes to Anaerobic Respiration  Does not produce ATP  Does produce molecules that can be used in other processes to produce ATP  2 most common fermentation pathways: –LACTIC ACID FERMENTATION –ETHYL ALCOHOL FERMENTATION

27. LACTIC ACID FERMENTATION  Helps produce some foods, ex) yogurts and cheeses  Also occurs in your muscle cells during very strenuous exercise…such as sprinting at top speeds  As lactic acid accumulates…it reduces the ability of the muscle cells to contract…resulting in fatigue, pain, and cramping

28. ALCOHOLIC FERMENTATION  Used by some plant cells and unicellular organisms  Used in the wine and beer industries and in the making of breads.

29. AEROBIC RESPIRATION  Occurs when Oxygen is present in the cell  Produces more ATP (nearly 20 times as much as is produced by glycolysis alone  Takes place in the mitochondria  2 major stages –The Kreb’s Cycle –Electron Transport Chain

30. THE PRODUCTION OF ATP

31. 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 CO 2, hydrogen atoms, and ATP  1 Glucose molecule gives 2 cycles of the Kreb’s cycle and produces: –6 NADH –2 FADH 2 –2 ATP –4 CO 2

32. 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 FADH 2 from Kreb’s produce a total of 4 ATP  Electron Transport Chain Produces a TOTAL of 34 ATP

33. CELLULAR RESPIRATION  THE ENTIRE PROCESS CAN PRODUCE A TOTAL OF 38 ATP

35. 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?

36. 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.

37. 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

38. 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?