Photosynthesis is the process by which plants, algae, and some bacteria use sunlight, water and carbon dioxide to produce oxygen and energy in the form of glucose. It occurs in two stages: the light-dependent reactions in which light energy is absorbed and used to produce ATP and NADPH, and the Calvin cycle where ATP and NADPH fuel the building of glucose molecules from carbon dioxide. Chlorophyll and other pigments are key to absorbing sunlight during the light-dependent reactions, which also produce oxygen as a byproduct. The energy-carrying molecules like ATP and NADPH are then used in the dark reactions to fix carbon from carbon dioxide into organic compounds like glucose.

1. PhotosynthesisPART 1: Basic Vocabulary & ATP

2. EnergyEnergy – the ability to make something happenENERGY exists in different forms, but can CHANGE from one form to another.Some types of energy are:Light (solar)Electrical ChemicalInfrared (heat)

3. “Solar cells” convert LIGHT (solar) energy into ELECTRICAL energy (electricity).Light bulbs convert ELECTRICAL energy back into LIGHT (and heat!) energy.This is one way humans store ENERGY for later use.

4. EVERYTHING has some form of energy, or a COMBINATION of different forms of energy. A light bulb has LIGHT and HEAT energy to offer.Remember: All energy originally comes from the SUN.Energy CANNOT be createdEnergy cannot be DESTROYEDBut, energy CAN be transformedThe energy to power your iPodcame from the sun, originally.Have you thanked your Sun recently???

5. Have you ever used a solar-powered calculator? No matter where you go, as long as you have a light source, the calculator works. You never have to put batteries in it.Where does the energy to power the calculator come from? What form (light/heat/chemical/electrical) of energy is this?A solar cell transforms this energy into ___________ energy, which powers the electrical circuits of the calculator.Do all calculators run on solar energy?

6. Have you ever noticed that your body maintains a constant temperature, usually 98o F?This energy, measured by temperature, is HEAT energy.Which object has more heat energy, an ice cube or a hot cup of coffee?What happens when you put the ice cube into the hot coffee?It melted, but why?The energy moved from the coffee (area of higher energy) into the ice cube (area of lower energy), giving it enough energy to melt.Since energy moves from an area with lots of energy to an area with lower energy, what happens to the air next to your skin on a cold day?When you use a wood stove to put energy into your house, what happens to the temperature inside your house?Where did the energy come from to heat the stove?Where did the energy in the wood come from?

7. The energy in the wood from the last example came from the SUN, originally.The wood has lots of trapped CHEMICAL energy.Chemical energy is stored in the BONDS between molecules of the wood. These bonds are BROKEN when wood is burnt. When chemical bonds are broken, energy is RELEASED. How did the wood transform energy from the sun (light energy) into chemical energy?Photosynthesis– making chemical energy from light energyPhotosynthesisPhoto – “light” Synthesis – “making”

8. Energy in OrganismsJust like our appliances, iPods, and light bulbs have energy flowing through them, energy flows through LIVING things!Energy to power LIFE originally comes from the SUN, just like all other energy.Energy from the sun enters living systems through “producers,” such as autotrophs.Autotrophs – make their own food by photosynthesis gathers LIGHT energy and stores it as CHEMICAL energy in GLUCOSE.

9. What are examples of autotrophs?PlantsOak treeGrassWheatMossFlowersShrubsEvery other plant you can think of.AlgaeAlgae are not considered plants – they are unicellular.Certain kinds of bacteria

10. Comparing AutotrophsPhotoautotrophsVs. Chemoautotrophs

11. PhotoautotrophsConvert light energy into chemical energy stored in organic compounds (usually glucose).This is PHOTOSYNTHESISSource of energy is the SUNExamples: Plants, algae, and other “green things” with photosynthetic pigments (such as chlorophyll).

12. Photoautotrophs

13. ChemoautotrophsUse small, inorganic molecules to make larger organic molecules that sustain lifeEg) CO2, NH3, NO2-, H2, Fe2+Usually don’t need sunlightMany archaebacteria are chemoautotrophsFound deep in ice-core samples in GreenlandFound in extremely salty conditionsFound on bottom of ocean in near-boiling water

15. HeterotrophsOrganisms that must get energy from food instead of directly from sunlight or inorganic substances.Heterotrophs extract the energy from food through the process of cellular respiration.Cellular respiration produces ATPIncludes: animals, fungi, some protists, some bacteria

16. HeterotrophsAutotrophs

17. ATP ATP is Adenosine TriPhosphate.Is a nucleotide (but doesn’t form DNA)Is the cell’s energy currency.Chemical energy held in bonds between phosphates

18. ATPADENOSINE DIPHOSPHATEENERGYRELEASEDADENOSINE TRIPHOSPHATE

19. ADPATPEnergyEnergyAdenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP)PartiallychargedbatteryFullychargedbattery

20. ENERGYPART 2: PHOTOSYNTHESISTracking the flow of energy where it enters living things: plants.

21. The site for photosynthesisPhotosynthesis occurs in the leaves.

22. The leaves also serve as the site where CO2 and O2 are absorbed and released.

23. Water is absorbed by the roots of the plantPHOTOSYNTHESISProcess that converts LIGHT energy into CHEMICAL energy.MEMORIZE THE FORMULA!!!H2O + CO2 + LIGHT C6H12O6 + O2 Water Carbon DioxideGlucose Oxygen

24. How does the plant get CO2 and release O2?Leaf  plant organ where photosynthesis occursStomata  small pores underneath the plant leaf where carbon dioxide and oxygen to diffuse in and outGuard Cells  cells that surround stomata that open and close according to water pressure

25. Equipment UsedThe Chloroplast is where photosynthesis occurs in the plantThe chloroplast has an inner and outer membrane.The inner membrane forms disk-shaped structures called thylakoidswhich has chlorophyll embedded in it.Thylakoids arranged in stacks called granaThe space around the thylakoids is the stroma

26. THYLAKOIDSTROMA

28. PigmentsPigments (such as CHLOROPHYLL) reflect the colors that they can NOT absorb.Ex: a red shirt can absorb orange, yellow, green, blue, indigo, and violet but can NOT absorb red so it reflects (and appears) red to your eyes.QUESTION: Which color light will be more effective for plant growth?YellowGreenRed

29. There are two types of chlorophyll.

30. Chlorophyll A and Chlorophyll B

31. What color of light is absorbed the most by Chlorophyll b?

32. What color of light is absorbed the most by Chlorophyll a? Absorption of Light byChlorophyll a and Chlorophyll bChlorophyllbChlorophyllaVBGYOR

33. PigmentsChlorophyll isn’t the only pigment in plants.Accessory pigments - absorb different wavelengths (colors) of light than chlorophyll allowing the plant to absorb more light energy during photosynthesis.Carotenoids – appear orange and yellowGive the fall leaves their colors

35. Pigments inspire art

36. PHOTOSYNTHESIS: STEP 1Step 1 – Light-Dependent ReactionsChlorophyll in the thylakoid membrane absorbs photons (light energy), which excites electronsElectrons bounce down an “electron transport chain” (ETC)ETC – a group of integral membrane proteins that ferry electronsAs electrons pass through, these proteins pump H+ across the membraneWateris broken to resupply lost electronsByproducts: Oxygen and H+H+ gradient powers ATP formationElectrons hop off the chain and onto NADP+, forming NADPH.

37. Products of Light ReactionsATP and NADPH (high-energy compounds)Needed to power the next stepOxygen (released into atmosphere)

38. PHOTOSYNTHESIS: STEP 2STEP 2 – Dark Reactions aka. Calvin cycleOccurs in the stromaDoes NOT require lightThe ATP and NADPH produced in the light-dependent reactions is used to power the conversion of CO2 into glucose (C6H12O6)NADPH converted back into NADP+ATP converted back into ADPBoth NADP+ and ADP go back to the light reactions to get recharged

39. Chloroplast – Overview of Light-Dependent Reactions and Calvin Cycle

41. LIGHT ENERGYH2O

42. LIGHT ENERGYH2OATPNADPHO2

43. LIGHT ENERGYCO2H2OCALVIN CYLE/DARK REACTIONATPNADPHO2

44. LIGHT ENERGYCO2H2ONADP+ADPCALVIN CYLE/DARK REACTIONATPNADPHO2C6H12O6 (Glucose)