CHAPTER 8 PHOTOSYNTHESIS

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

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