2StandardsCLE Investigate the relationship between the processes of photosynthesis and cellular respiration.SPI Compare and contrast photosynthesis and cellular respiration in terms of energy transformation.
3Objectives Summarize the reactants and products of photosynthesis. Describe the reactants and products of the light reactions.Describe the reactants and products of the Calvin Cycle (dark reactions).Summarize how the light reactions and Calvin cycle work together to create a continuous cycle of photosynthesis.
4Q: Where does the energy come from in each stage of the food chain? Think – Pair - ShareQ: Where does the energy come from in each stage of the food chain?
7WHAT is the energy?Much of the energy used by living organisms is in the form of ATP
8Chemical Energy and ATP The principal chemical compound that cells use to store and release energy is called ATP (adenosine triphosphate)
9Storing EnergyATP stores energy in the bond between the second and third phosphate groupATP is like a fully charged batteryEnergy
10Releasing Energy Think – Pair - Share Q: How is the energy in ATP released? A: Break bond between the second and 3rd phosphates2ADP
11ATP vs. ADP ATP – has all 3 phosphate groups Fully charged batteryBrief energy storageCan remove a phosphate group to release energy and form ADPADP – has only 2 phosphate groupsPartially charged batteryCan add a phosphate group to make ATP
14ATP AvailabilityMost cells only have enough ATP for a few seconds of activityWhy?Not good at storing energy over the long termGlucose stores 90 times the chemical energy of ATPCells generate ATP from ADP as needed by using the energy in foods (like glucose)
20Pigments Absorb different wavelengths of light (colors) Reflect (transmit) what they do not absorbWe see what is reflected back.
21Chlorophyll The plant’s principal pigment absorbs light energy blue-violetred
22Chlorophyll a and Chlorophyll b Absorption of Light byChlorophyll a and Chlorophyll bAbsorption of Light byChlorophyll a and Chlorophyll bChlorophyll bChlorophyll aVBGYOR
23Think – Pair - ShareQ: Why are leaves green?A: because chlorophyll absorbs the blue-violet and red light and reflects the green back.
24Because light is a form of energy… Anything that absorbs light also absorbs the energy from that lightWhen chlorophyll absorbs light, much of the energy is transferred to electrons in the chlorophyll molecule, raising the energy level of these electronsThese high-energy electrons make photosynthesis work
25Photosynthesis Basics Where does photosynthesis take place?In organelles called chloroplasts.
34Light Dependent Reactions “photo” part of photosynthesisReactants:H2O, energy from light (photons) NADP+, ADP+ and phosphate groupProducts:Oxygen gas, ATP, NADPH
35Think – Pair – ShareQ: Where did the Oxygen, produced by the light dependent reactions come from?A: H2O
36What you need to know: Where do the light reactions occur? What is needed (reactants)?What is created (products)In the thylakoids.Light (photons)waterATP & NADPH - go on to Calvin cycleOxygen - that is released
37Carrier MoleculeCompound that can accept a high energy electron and transfer it along with most of its energy to another moleculeEx.) NADP+ + H NADPH
38The Calvin Cycle The “synthesis” part of photosynthesis These reactions don’t require light, therefore these reactions are called Light – Independent or Dark reactions
39The Calvin CycleReactants: ATP and NADPH (from light – dependent reactions) and CO2Products: high energy sugars (C6H12O6) and NADP+ and ADP+ (which will go back to light dependent reaction for reuse)
40Carbon Fixation The incorporation of CO2 into organic compounds The Carbon in CO2 is “fixed” into the usable energy form of sugar6 CO2 molecules will go into the cycle to produce each organic molecule of 6-Carbon sugar. (C6H12O6 )
42Factors Affecting Photosynthesis Not enough waterTemperatureLight intensityCO2 levels
43Objectives (Did we…)Summarize the overall reactants and products of photosynthesis.Describe the reactants and products of the light reactions.Describe the reactants and products of the Calvin Cycle (dark reactions).Summarize how the light reactions and Calvin cycle work together to create a continuous cycle of photosynthesis.