Chapter 4: Energy

1. Chapter 4: Energy From the sun to you in two steps Yummy Food !!! Jack Fruit How photosynthesis uses energy from sunlight to make food: Know all the steps !!! http://www.youtube.com/watch?v=ww33L0lD37I

2. What has photosynthesis got to do with global warming? How to reduce global warming? Increase photosynthesis Ocean: algae Plant more trees Lock up products of photosynthesis Carbon capture farming

3. Photosynthesis Source of Biofuels • Corn • Soybeans • Switchgrass • Jatropha seeds • Waste products (corn husks) • Algae • Diatoms Source of food but also source of biofuels

4. Plant metabolism… PHOTOSYNTHESIS • occurs in the green canopy, and • makes sugars CELL RESPIRATION • occurs in roots and other tissues, and • uses stored sugars for energy BIOSYNTHESIS (ANABOLISM) • occurs in all parts of plant • uses sugars & energyto make other materials Bizarre tree in Greenville, SC

5. Photosynthetic Organisms Sea slug: Elysia chlorotica

6. While gazing into an aquarium you observe bubbles coming from an aquatic plant. What are the bubbles and where are they coming from? • Carbon dioxide ; Water • Carbon dioxide; Plant • Oxygen; Water in tank • Oxygen; Plant

7. Why do scientists study photosynthesis?

8. Where does plant mass come from? Photosynthesis: the big picture. From a seed to a tree: Where does the plant mass (growth) come from? From the soil From the water From the air

9. Photosynthesis: The Big Picture 3 inputs: _____, _______ and _____ 2 products ______ and _______ Overview of Photosynthesis

10. Photosynthesis take place in the chloroplasts Chloroplasts - organelles in plant cells Chlorophyll: ________________

11. Chloroplast Anatomy Innermembrane Outer membrane Intermembrane space Thylakoid Stroma (outside thylakoids) Thylakoidcompartment (inside) Figure 7.2

12. Why leaves look green? Chlorophyll: • Plant pigment • Absorbs certain wavelengths of energy (photons) from the sun • Absorbed energy excites electrons

13. Why are leaves orangein fall? Bionic plant:

14. How does the pigment composition of a leaf change from spring to fall? A. Decreased amount of chlorophyll a & b in the fall B. Increased amount of carotenoids in the fall C. Carotenoid levels remain constant D. A and B E. A and C

16. An overview of photosynthesis (inside a chloroplast) Two parts of photosynthesis Light reactions (photo part) Calvin Cycle (synthesis part) thylakoids Carbon Fixation Parts of the light reactions Two photosystems An electron transport system Enzyme: ATP synthase

17. What is a Photosystem?

18. Photolysis:_____ Electron Transport: Electron transfer to NADP+:

19. The “Photo” Part (light reactions)

20. How are the electrons lost from PS II, replaced? • They come from PS I • They come directly from sunlight • They come from ATP • They come from water

21. What occurs during light reactions?

22. Summary of the two photosystems • PSI • ETC : builds up _____ • PSII • ATP Synthase

23. Photosynthesis animation • http://wps.prenhall.com/esm_freeman_biosci_1/0,6452,498648-,00.html • www.fw.vt.edu/dendro/forestbiology/photosynthesis.swf • http://dendro.cnre.vt.edu/forestbiology/photosynthesis.swf

24. What is the role of electron transport chain? • It donates electrons to PSII • It is necessary to split water to generate oxygen C. It creates a proton gradient that is used by ATP synthase to make ATP D. It makes NADP www.fw.vt.edu/dendro/forestbiology/photosynthesis.swf

25. What accumulates inside the thylakoid during the light reactions? • Glucose • Hydrogen ions • Oxygen • Carbon dioxide

26. The Calvin Cycle Series of chemical reactions Occurs in stroma Enzymes are recycled

27. Inputs in the Calvin cycle….. 1. Enzyme: Rubisco helps in Carbon fixation in the Calvin cycle 2. RuBP 5 Carbon compound : which is the starting compound in Calvin cycle 3. Carbon dioxide: taken by the plant is used in calvin cycle

28. The Processes in the Calvin Cycle Occur in Three Steps:

29. INPUT: CALVINCYCLE OUTPUT: Calvin Cycle • Input: • Output: Where: Enzyme: GLUCOSE

30. Chloroplast Light PS IIETS PS I CALVIN CYCLE Stroma Electrons Cellular respiration Cellulose Starch Other organic compounds LIGHT REACTIONS CALVIN CYCLE

31. The actual sugar production takes place___ A. Within the membrane of the chloroplast B. Within the stroma, inside the chloroplast C. Within the thylakoid membrane D. Just outside the chloroplast, within the mitochondria

32. What is the role of the Calvin reactions of photosynthesis? A. To convert carbon dioxide to sugar B. To generate ATP and NADPH C. To make oxygen D. To convert ATP into sugar

33. Photosynthetic adaptations • World hunger is related to low crop productions in hot dry areas (Africa) In hot dry conditions the stomata closes If stomata closes then -Oxygen builds up -CO2 is depleted But this is a problem for plants….

34. Evolutionary AdaptationsC4 and CAM plants Some plants thrive in hot, dry conditions Adaptations that reduce evaporative water loss Allows for Calvin cycle to continue

35. Plants from hot, dry areas are able to prevent this waste of energy Corn and Sugarcane are “C4 plants” • have better enzyme: PEP carboxylase • First compound is 4 C called _____ • have special leaf anatomy that allows cells to store CO2

36. With global warming, many scientists expect the ______ to be pushed farther away from the equator. • C4 crop plants • C3 crop plants

37. CAM Plants in extreme hot, dry areas • Jade plants, cacti, & pineapples are “CAM plants” • Close stomata at day • Open stomata at night and store CO2 in the form of acid • CO2 from acid is released in cells during daytime so that rubisco can fix CO2

38. Different Pathways of Carbon Fixation C4 CAM C3

39. Plant Engineered for better photosynthesis Nature, Sept 17, 2014 Tobacco plant that has been genetically engineered to carry out carbon fixation by transfering the rubisco gene from a ____________

40. CAM plants can carry on photosynthesis even if their stomata are closed during daytime • True • False