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Today is Wednesday, October 30 th , 2013

In This Lesson: Photosynthesis (Lesson 2 of 3). Today is Wednesday, October 30 th , 2013. Pre-Class: Why are plants green? (Or why are the green parts of them green, at least?) Other stuff: Turn in your homework if you did it on paper. Grab a [small] paper towel for your pair.

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Today is Wednesday, October 30 th , 2013

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  1. In This Lesson: Photosynthesis (Lesson 2 of 3) Today is Wednesday,October 30th, 2013 Pre-Class: Why are plants green? (Or why are the green parts of them green, at least?) Other stuff: Turn in your homework if you did it on paper. Grab a [small] paper towel for your pair.

  2. Today’s Agenda • Photosynthesis • Photosynthesis • And maybe flamingos. http://www.harunyahya.com/kids/pictures/wallpaper1024/flamingo.jpg

  3. ATP Review • Think of ATP (Adenosine Triphosphate) as a molecule like a chocolate bar. • “Not another analogy!” • The cell can break off a square to make it ADP. • That releases energy. • The cell can put a square on (add a phosphate group to ADP, making ATP), but that’s hard to do. • You’d need to melt it down in an oven and re-form it. • That absorbs (uses) energy.

  4. Simple Diagram(worth sketching…no, really) http://mrsec.wisc.edu/Edetc/nanoquest/molecular_motor/images/atpenergy.jpg

  5. Watching Plants Grow • First, where is this in my book? • P. 204 and following… • As usual, here are the historic figures related to Photosynthesis: • Van Helmont • Priestley • Ingenhousz • [your name here]

  6. 1600s: Jan van Helmont • Belgian physician – tries to figure out if plants take mass from soil to grow so large. • Measured soil, planted a seed, and watered it. • Then he waited five years (!). The soil weighed the same as it did five years earlier. • CONCLUSION • The plant is using water (hydrate) to grow. (it’s also using CO2 but he didn’t catch that part) • Jan van Helmont also coined the word “gas.” Floating head! Spooky… http://2.bp.blogspot.com/_XU9nEwykZRc/SkO5s53xzgI/AAAAAAAAACU/gUPGWU3wpbo/s320/van_Helmont.jpg

  7. 1700s: Joseph Priestley • English minister – noticed that a candle will go out if you put a glass jar over it. • Flames need oxygen as fuel. • However, if you put a leaf in there (he used mint), the candle burns longer. • CONCLUSION • Plants produce oxygen. • Priestley also named rubber. Hmmph. ‘alloguv’nah!! http://explorepahistory.com/images/ExplorePAHistory-a0h1r8-a_349.jpg

  8. Aside: Great Moments in Science • Turns out that Priestley wasn’t the first to discover oxygen, though he got all the credit. • Previously, Carl Scheele discovered oxygen and seven other elements, unfortunately receiving credit for none of them. • Also unfortunate: Scheele had a habit of tasting all the chemicals with which he worked. • He was found dead at the age of 43 surrounded by several toxic chemicals.

  9. 1700s: Jan Ingenhousz I am grayscale. • Dutch scientist – noticed that air bubbles only form around aquatic (underwater) plants when they are in sunlight. • The air bubbles are oxygen from photosynthesis. • No bubbles formed in darkness. • CONCLUSION • Plants need sunlight to make oxygen. http://0.tqn.com/d/chemistry/1/0/W/1/1/Jan_Ingenhousz.jpg

  10. 2013: You. • Here’s an interesting question: • Suppose you put soil and some water in a clear jar. • Then you plant a seedling in that soil. • Then you put a lid on the jar, sealing the air. • Lastly, you set it on a windowsill so it gets a normal amount of light and heat. • What happens?

  11. The Magic Photosynthesis Machine YE OLDE PHOTOSYNTHESIS MACHINE ? ? INPUT OUTPUT

  12. Photosynthesis: An Outline • Photosynthesis is basically this: • 6CO2 + 6H2O + [LIGHT]  C6H12O6 + 6O2 • In other words, it’s a conversion of light energy to chemical energy. • Plants use it to convert and store energy. • What you should do is this: • Write down the chemical formula. • Write down the formula in English. • Draw the formula in mini-diagrams. • (2 minutes to work)

  13. Photosynthesis • First, some review: (whiteboards) • In which organelle does photosynthesis occur? • What is a pigment? • What’s the name of the pigment inside chloroplasts? • What color is it? • Chlorophyll appears green to us because it is reflecting green light. Therefore, it’s absorbing every other color but green*.

  14. *Disclaimer • Technically, when a color is transmitted to us, only a complementary color is absorbed:

  15. The Big Aside • TED: David Gallo – Underwater Astonishments • Other people’s colors • Do I See Colors The Same Way You Do? • A Bee’s Eye View article • Ishihara Test • Stop sign color experiment and night vision • TED: Beau Lotto – Optical Illusions • Primary colors • Upside-down perception • Vision correction

  16. Ishihara Test http://www.toledo-bend.com

  17. Ishihara Test http://www.toledo-bend.com

  18. Perception • The image of the world around you strikes the retina in the back of the eye upside-down. • Your brain “flips” the image for you. Kinda. http://www.diycalculator.com/imgs/cvision-upside-down.gif

  19. Vision Correction http://www.d.umn.edu/~jfitzake/Lectures/DMED/Vision/Optics/Figures/RefractiveErrors.gif

  20. The Chloroplast Sketch it like you mean it! Grana

  21. Chloroplast Structure(It’s not just an oval) • Two membranes • The inside of the inner membrane is called the stroma. • Stacks of “disk-like structures.” (Holt: Biology) • The disks are called thylakoids. • The stacks are called grana (singular: granum). • Contain chlorophyll (pigment). • Light hits chlorophyll and chlorophyll reacts!

  22. RapidTrivia! • It’s time for something new I’m going to try. • Grab your whiteboards, grab your markers, and get your partner’s attention. • I’m going to post a series of trivia questions about today’s topics or recent ones, including an off-topic bonus question. • Write down your answers QUICKLY! • Got the right answer? Fantastic, give yourself a star. • Got the wrong answer? Write down the topic of the question and review it later. • Unless it’s the off-topic bonus question.

  23. Question #1 • What is the name of the innermost “space” of the chloroplast? • Stroma

  24. Question #2 • What is the name of the disk-like structures inside the chloroplasts? (just the disks, not the stacks!) • Thylakoids

  25. Question #3 • What are the two products of the photosynthesis reactions? • Sugar (glucose) and oxygen

  26. Question 4* • Why did bald eagles become so endangered in the mid-20th century? • DDT (dichlorodiphenyltrichloroethane) *Off-topic

  27. “Illuminating Photosynthesis” • Before we get to pigments and the “nuts and bolts” of this whole process, we’re going to see a really nice animation of the whole process in general. • Please take the time to read through it carefully – this will help! • It’s available here: • http://www.pbs.org/wgbh/nova/methuselah/phot_flash.html

  28. Photosynthesis: Pigments • There are three main pigments: • Chlorophyll A • Chlorophyll B • Carotenoids • There are also Anthocyanins – they help make leaves change color in the fall. • “Hard to place” fact: • Chlorophyll reflects green light!

  29. Carotenoids: A Brief Aside I know you think my beak is attractive. • In plants: • Carrots • Oranges • Fall leaves • In animals: • Flamingos • Zebra Finches • Et cetera http://www.rbgsyd.nsw.gov.au/__data/assets/image/0011/88535/Taeniopygia_guttata_Zebra_Finch_620.JPG

  30. Back on topic… http://www.pearsonsuccessnet.com/snpapp/iText/products/0-13-115075-8/text/chapter8/08images/08-02.gif

  31. Chloroplasts http://www.school.net.th/library/create-web/10000/science/10000-6528/pic2.jpeg

  32. Chloroplasts http://www.vialattea.net/spaw/image/biologia/May2005/thylakoids2.jpg

  33. Let’s summarize…

  34. Let’s summarize…

  35. Photosynthesis Lab Gizmo! • Today we’re going to look at a photosynthesis gizmo. Also please complete the Photosynthesis Lab Gizmo quiz on Quia. • [Log-in Instructions]

  36. Photosynthesis Reactions • There are two overall parts of Photosynthesis: • The Light Reactions (or Light-Dependent Reactions) • [because the plant needs light for them] • The Calvin Cycle (or Light-Independent Reactions) • Also called “The Dark Reactions” • [because the plant doesn’t need light for them]

  37. Light Reactions • Where: The thylakoid membrane. • Needs: Light and Water (H2O) • Makes: ATP and protons (H+) • Waste: Oxygen • Note: Even though oxygen is waste, it’s still a product.

  38. Photosynthesis Reactions 6CO2 + 6H2O C6H12O6 + 6O2 Light Reactions Light Reactions

  39. Light Reactions • Three Steps: • Light excites chlorophyll’s electrons (makes them go to higher energy). • Electrons travel down the thylakoid membrane as they lose energy. (leave some space in your notes) • The electrons power the thylakoid to make ADP into ATP. (leave some space in your notes) • This thing is called the electron transport chain, by the way, and it’s much like electricity flowing through a strand of holiday lights. e-

  40. Electron Transport Chain STROMA SPACE e- THYLAKOID SPACE H+ http://bioweb.wku.edu/courses/Biol120/images/non-cyclic1.jpg

  41. ETC • And what do those electrons power? • Electrons power a proton pump which brings protons into the thylakoid space. • And then… • Protons passively diffuse out through a protein/enzyme complex called ATP Synthase. • ATP Synthase “harvests” the motion of diffusion to synthesize ATP from ADP and free phosphate groups. • Much like a hydroelectric dam harvests water flow.

  42. The Calvin Cycle/Dark Reactions • Where: The Stroma • Needs: ATP and protons (H+) [from the Light Reactions] and CO2 [from the air] • Makes: Glucose (sugar/carbohydrate) • Side note: named after Melvin Calvin.

  43. Photosynthesis Reactions 6CO2 + 6H2O C6H12O6 + 6O2 Light Reactions Light Reactions Calvin Cycle Calvin Cycle

  44. Summary • The light reactions use sunlight to make ATP (and some by-products). • The dark reactions use that ATP to make glucose.

  45. Closure • Let’s do a WhipAround, shall we? • Write down one new vocabulary word from today or yesterday and its definition. • Stand up once you’re done.

  46. Water Weed Lab • This is a written lab report. • Specific requirements and a rubric are listed on the reverse of your lab sheet. • You will be taking a virtual look at an aquatic plant (Elodea) and analyzing photosynthetic rate as a function of three particular conditions: • Light Level • Light Color • CO2 Level • You will need to create a graph for your final lab report. • The graph can be created in Excel, by hand, or with an online graphing tool. • Create-a-Graph (in Biology Links – Various Units section) • http://nces.ed.gov/nceskids/createagraph/default.aspx • TIP: Select “X5” to run the simulator faster.

  47. Closure • TED: Amanda Ooten – The Simple Story of Photosynthesis and Food

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