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CHAPTER 8 PHOTOSYNTHESIS

CHAPTER 8 PHOTOSYNTHESIS. SECTION 8-1 ENERGY and LIFE. Question of the Day OCT 25. Which of the following organisms is an autotroph? A. Giraffe B. Antelope C. Maple tree D. Polar bear. DO NOW OCT 25. IT’S BACK!!! ADAM C., NICOLE L., and TYLER

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CHAPTER 8 PHOTOSYNTHESIS

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  1. CHAPTER 8 PHOTOSYNTHESIS SECTION 8-1 ENERGY and LIFE

  2. Question of the Day OCT 25 • Which of the following organisms is an autotroph? • A. Giraffe • B. Antelope • C. Maple tree • D. Polar bear

  3. DO NOW OCT 25 • IT’S BACK!!! • ADAM C., NICOLE L., and TYLER • YOU are the next contestants on DO NOW CHALLENGE!!!

  4. DO NOW CHALLENGE OCT 25 • Explain why plants have a key role in the survival of all living things. • Answer the DO NOW in your notes if you are at your desk.

  5. DO NOW ANSWERED • Plants (and some algae) perform photosynthesis. They produce their own food in the form of sugar. • Other living organisms depend on this source of food to power their own cells. • Ultimately, all life is dependent upon plants from the smallest herbivore to the pinnacle predators of our planet.

  6. AGENDA OCT 25 • BIG Question: How do organisms obtain and store energy? • 1. QoD and DO NOW • 2. Introduce Chapter 8 Photosynthesis • 3. Review Guided Notes Packet • 4. REVIEW • 5. HOMEWORK and Closing Thoughts

  7. AUTOTROPHS AND HETEROTROPHS • What is the key source of energy for most food? • THE SUN • Plants and other organisms such as blue-green algae use light energy from the sun to produce food. • These organisms are called AUTOTROPHS. • Use simple inorganic molecules to do this.

  8. AUTOTROPHS and HETEROTROPHS • Heterotrophs are organisms that obtain energy from the food they consume. • Unable to use sunlight directly. • ALL organisms must release energy in sugars and other compounds.

  9. CHEMICAL ENERGY and ATP • What are three forms of energy? • Light, heat, and electricity • Energy can be stored in compounds. • Electrons release energy when a piece of wood is set on fire. • When chemical bonds are broken and electrons shift from higher energy levels to lower energy levels, the extra energy is released as light and heat.

  10. CHEMICAL ENERGY and ATP • How do organisms such as humans store and release energy? • Cells use chemical compounds to do this. • What is ATP? • Adenosine Triphosphate (ENERGY storing molecule) • ATP consists of ADENINE, a 5-CARBON SUGAR, and 3 PHOSPHATE GROUPS

  11. STORING ENERGY • What is ADP? • ADENOSINE DIPHOSPHATE • 2 PHOSPHATE GROUPS • Partially charged battery • This is the key molecule organisms use to store excess energy when it is available. • To store energy, a PHOSPHATE group is added to ADP. • This creates a molecule of ATP. • ATP is like a fully charged battery. WHY?

  12. RELEASING ENERGY • How is stored energy released from ATP to be used by the cell? • Energy is stored in the chemical bond between the second and third phosphate groups. • Breaking this bond releases the energy stored in it.

  13. RELEASING ENERGY • ATP is the basic energy source for all cells. • What are different cellular functions that ATP can power within the cell? • ACTIVE TRANSPORT • PROTEIN SYNTHESIS • MUSCLE CONTRACTION

  14. USING BIOCHEMICAL ENERGY • What is a SODIUM – POTASSIUM Pump? • Used during Active Transport • It pumps Na- ions out of the cell and K+ ions into it • Balance of ions must be carefully regulated. • Why do most cells only have a small amount of ATP? • Not a good molecule for storing large amounts of energy over a long period of time. • Glucose stores 90 times more energy than ATP • Cells regenerate ATP from ADP as they need it.

  15. QUESTION OF THE DAY OCT 28 Where is energy stored in a molecule of ATP? • The phosphate groups • The ribose • The bond between the first and second phosphates • The bond between the second and third phosphates

  16. DO NOW CHALLENGE OCT 28 • STEP UP to the boards. • Answer the Challenge in your notes if you are at your desks.

  17. DO NOW CHALLENGE OCT 28 • Compare a molecule of ATP and Glucose. • How are they similar/different in their role of storing energy?

  18. ANSWER OCT 28 • ATP is the cell’s short term energy storing molecule. Energy is stored within ATP in the chemical bond formed between the second and third phosphate groups of the molecule. In order to release this energy, the bond must be broken. • Glucose is a monomer that forms carbohydrates. Many of these simple sugars form glycogen. It is used to store sugars for long term energy use. • THANK YOU FOR PLAYING DO NOW CHALLENGE!!!

  19. AGENDA OCT 28 • BIG QUESTION: How did early experiments lead to the discovery of photosynthesis? • 1. QoD and DO NOW • 2. Section 8-2 Photosynthesis: An Overview • 3. Discovery of Photosynthesis • 4. Homework Check • 5. Review and Homework • 6. Return CH 7 Tests and Cell Booklets

  20. 8-2 Photosynthesis: An Overview • What is PHOTOSYNTHESIS? • Plants use the energy of sunlight to convert water and carbon dioxide into high energy carbohydrates • Sugars and starches • And Oxygen, a waste product.

  21. Investigating Photosynthesis • As a tree grows bigger and bigger in size, where does the tree’s increase in mass come from? • SOIL, WATER, AIR? • This simple question asked hundreds of years ago began the research into photosynthesis. • Let’s take a closer look at some of the experiments that led to the discovery of photosynthesis…

  22. Van HELMONT’S Experiment • 1643, Belgian physician Jan van Helmont. • What did he do? • Designed an experiment to investigate if plants grew by taking materials out of the soil. • His experiment? • 1. Determined mass of a pot of dry soil and a seedling.

  23. Van HELMONT Experiment • 2. Planted the seedling in the pot of soil. • Watered regularly. • 3. At the end of 5 years, the seedling had grown into a small tree. Mass gain of 75 grams. • 4. Mass of soil remained almost unchanged. • 5. His Conclusion • Mass of the tree came from the water – only thing he added. • Accounted for the “HYDRATE” portion of a CARBOHYDRATE • Where does the “CARBO” portion come from? • Carbon Dioxide

  24. Priestley’s Experiment • 1771, English minister Joseph Priestley • What did he do? • Lit a candle, placed a jar over it, and watched the flame gradually die out. • What did he reason about the candle flame? • Something in the air was necessary to keep the candle burning.

  25. Priestley’s Experiment • What was his next step? • He placed a spring of mint underneath the jar with the candle. • After a few days, Priestley realized that the candle could be relighted. • It would remain burning for a period of time. • His conclusion? • The mint sprig released something needed to keep the candle flame burning. • What was this mystery substance? • OXYGEN

  26. The Ingenhousz Experiment • 1779, Dutch scientist Jan Ingenhousz • What did he do? • Showed the effect observed by Priestley only occurred when the plant was exposed to light. • What did these experiments show? • When a plant is exposed to light, it transforms carbon dioxide and water into carbohydrates and release oxygen.

  27. PHOTOSYNTHESIS EQUATION • What is the balanced equation of photosynthesis? • Compare the equation of photosynthesis with another cellular process.

  28. Light and Pigments • White light is actually a mixture of different wavelengths of light called the visible spectrum • Different wavelengths of visible light are seen as different colors.

  29. Light and Pigments • What is a pigment? • colored substances that absorb or reflect light • Why are plants green? • chlorophyll: principle pigment in green plants • Absorbs red and blue-violet light in the visible spectrum. • Chlorophyll a and Chlorophyll b • Does not absorb green light well. Leaves reflect green light Which is why plants look green.

  30. Absorption of Light • B – carotene • Red and orange pigments that absorb light in other regions of the spectrum.

  31. ABSORPTION OF LIGHT

  32. Question of the Day • Which early scientist discovered that oxygen was the mystery substance produced by plants? • A. Joseph Priestley • B. Jan Ingenhousz • C. Jan van Helmont • D. Melvin Calvin

  33. AGENDA Oct 29 • BIG Question: What are light-dependent reactions? • 1. QoD • 2. Introduce Section 8-3 • 3. Watch Photosynthesis Video • 4. Complete Video Question Set • 5. Review and Homework • Chapter 8 Review Packet Sections 8-1 and 8-2 • STUDY YOUR NOTES EVERY DAY

  34. SECTION 8-3: The Reactions • The Chloroplast • Contains Thylakoids • Saclike photosynthetic membranes. • Arranged in stacks called GRANA (GRANUM) • Photosystems:clusters of chlorophyll and other pigments organized in the thylakoid membrane • Organized by proteins • LIGHT-Collecting Units of the Chloroplast

  35. 8-3: Reactions of Photosynthesis • Photosynthesis divided into two parts. • 1. Light-Dependent Reactions • Take place in the thylakoid membranes • 2. Light-Independent Reactions or The Calvin Cycle • Take place in the stroma – region outside the thylakoid membrane

  36. ELECTRON CARRIERS • Sunlight excites electrons in chlorophyll. • High-energy electrons require a special carrier. • Electron carriers transport high-energy electrons from chlorophyll to other molecules in the cell. • Called carrier molecules • Process is called Electron Transport • Electron carriers are called the Electron Transport Chain

  37. Question of the Day OCT 30 • The Light-Collecting Units of the Chloroplast are called • A. Stroma • B. Grana • C. Thylakoids • D. Photosystems

  38. DO NOW CHALLENGE OCT 30 • THREE VOLUNTEERS • STEP UP TO THE BOARD!!! • Thank you for playing DO NOW CHALLENGE

  39. DO NOW CHALLENGE OCT 30 • Describe the experiment of Jan van Helmont. • What did he discover about the mass of a tree? • Answer the Challenge in your notebooks if you are at your desks.

  40. AGENDA OCT 30 • BIG Question: What occurs in the Light-Dependent Reactions? • 1. QoD and DO NOW • 2. 8-3 NADP+ and Light Dependent Reactions • 3. Diagram of LD Reactions • 4. Closing Thoughts and Homework • 5. QUIZ SECTIONS 8-1 and 8-2 FRIDAY NOV 1 • ACADEMIC: HAND IN YOUR MICROSCOPE LABS • STUDY YOUR NOTES EVERY NIGHT • SEE ME AFTER SCHOOL/BEFORE SCHOOL/ON LUNCH IF YOU NEED EXTRA HELP!!!

  41. NADP+ AN ELECTRON CARRIER • Accepts and holds 2 High-energy electrons (e-) and a hydrogen ion (H+). • Converts NADP+ intoNADPH • This conversion is one way in which sunlight energy is trapped in chemical form. • NADPH then carries High-energy e- produced by light absorption in chlorophyll to chemical reactions elsewhere in the cell.

  42. Photosynthesis Reactions

  43. Draw Figure 8-7 in your NotesUse half a page for your diagram.Write down the question and the answer below your diagram. • Answer the following questions. • 1. What materials come into the chloroplast that are used in the light-dependent reactions? • 2. What material comes into the chloroplast that is used in the Calvin Cycle? • 3. What materials moves out of the chloroplast from the light-dependent reactions? • 4. What materials move out of the chloroplast from the Calvin Cycle? • 5. What materials move from the L-D reactions to the Calvin Cycle? • 6. What materials move from the Calvin Cycle back to the L-D reactions?

  44. LIGHT DEPENDENT REACTIONS • Why are they called LIGHT DEPENDENT REACTIONS? • They require light energy to take place. • Let’s look at the bigger picture. • What would happen if plants do not get sunlight? • Plants could not perform photosynthesis. • They would not produce sugars. • Or release Oxygen Gas into the atmosphere. • Other organisms like you and me(heterotrophs) would not be able to survive.

  45. LIGHT DEPENDENT REACTIONS

  46. LIGHT DEPENDENT REACTIONS • PRODUCE Oxygen gas • CONVERT ADP and NADP+ into energy carriers ATP and NADPH • STEP A: Pigments in Photosystem II absorb light. • What absorbs the light energy? • Electrons absorb light energy making them HIGH-Energy electrons • HIGH-Energy electrons passed to Electron Transport Chain (ETC)

  47. LIGHT DEPENDENT REACTIONS • STEP A CONTINUED: • Does chlorophyll run out of electrons? • No, Inner surface of thylakoid membrane has a system to provide new electrons. • Where do the new electrons come from? • WATER is broken down by enzymes. • 1 WATER molecule  2 H+ ions and 1 O atom • 2 H+ ions replace the HIGH Energy electrons passed to the ETC • Oxygen is released into the atmosphere

  48. LIGHT DEPENDENT REACTIONS • STEP B: HIGH-Energy electrons move through ETC from Photosystem II to Photosystem I • Energy used in ETC to transport H+ ions from Stroma to inner Thylakoid Space. • STEP C: Pigments in Photosystem I use light energy to recharge electrons. • NADP+picks up HIGH-Energy electrons and H+ ions on outer surface of thylakoid membrane. • NADP+ becomes NADPH

  49. LIGHT DEPENDENT REACTIONS • STEP D: H+ ions are pumped across the thylakoid membrane. • Inside of membrane fills up with H+ ions • Outside of membrane becomes negatively charged. • This difference in charges provides the energy to make ATP. • What is the importance of H+ ions?

  50. LIGHT DEPENDENT REACTIONS • STEP E: ATP SYNTHASE found in cell membrane. • What is ATP Synthase? • Allows H+ ions to pass through. • ATP Synthaserotates like a turbine being spun by water in a hydroelectric plant. • As ATP Synthaserotates, it binds ADP together with a Phosphate making ATP. • LD ETC produces HIGH-Energy electrons and ATP

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