3Why Would They Look Different? Different Stars Give off Different types of light or Electromagnetic WavesThe color of plants depends on the spectrum of the star’s light, which astronomers can easily observe. (Our Sun is a type “G” star.)
4Anatomy of a Wave Wavelength Is the distance between the crests of wavesDetermines the type of electromagnetic energy
5Electromagnetic Spectrum Is the entire range of electromagnetic energy, or radiationThe longer the wavelength the lower the energy associated with the wave.
6Visible LightLight is a form of electromagnetic energy, which travels in wavesWhen white light passes through a prism the individual wavelengths are separated out.
7Visible Light Spectrum Light travels in wavesLight is a form of radiant energyRadiant energy is made of tiny packets of energy called photonsThe red end of the spectrum has the lowest energy (longer wavelength) while the blue end is the highest energy (shorter wavelength).The order of visible light is ROY-G-BIVThis is the same order you will see in a rainbow b/c water droplets in the air act as tiny prisms
8Chloroplast – Where the Magic Happens! +H2OCO2EnergyATP andNADPH2Which splitswaterLight is AdsorbedByChlorophyllCalvin CycleADPNADPChloroplastUsed Energy and is recycled.O2+C6H12O6Light ReactionDark Reaction6 CO H2O + Light energy C6H12O6 + 6 O2 + 6 H2 O
9Light Options When It Strikes A Leaf ReflectedChloroplastAbsorbedlightGranumTransmittedFigure 10.7Reflect – a small amount of light is reflected off of the leaf. Most leaves reflect the color green, which means that it absorbs all of the other colors or wavelengths.Absorbed – most of the light is absorbed by plants providing the energy needed for the production of Glucose (photosynthesis)Transmitted – some light passes through the leaf
14Chloroplast Are located within the palisade layer of the leaf Stacks of membrane sacs called ThylakoidsContain pigments on the surfacePigments absorb certain wavelenghts of lightA Stack of Thylakoids is called a GranumChloroplastMesophyll5 µmOutermembraneIntermembranespaceInnerThylakoidGranumStroma1 µm
15Pigments Are molecules that absorb light Chlorophyll, a green pigment, is the primary absorber for photosynthesisThere are two types of cholorophyllChlorophyll aChlorophyll bCarotenoids, yellow & orange pigments, are those that produce fall colors. Lots of Vitamin A for your eyes!Chlorophyll is so abundant that the other pigments are not visible so the plant is green…Then why do leaves change color in the fall?
16Color ChangeIn the fall when the temperature drops plants stop making Chrlorophyll and the Carotenoids and other pigments are left over (that’s why leaves change color in the fall).
17Wavelength of light (nm) The absorption spectra of three types of pigments in chloroplastsThree different experiments helped reveal which wavelengths of light are photosynthetically important. The results are shown below.EXPERIMENTRESULTSAbsorption of light bychloroplast pigmentsChlorophyll a(a) Absorption spectra. The three curves show the wavelengths of light best absorbed by three types of chloroplast pigments.Wavelength of light (nm)Chlorophyll bCarotenoidsFigure 10.9
18The action spectrum of a pigment Profiles the relative effectiveness of different wavelengths of radiation in driving photosynthesis(measured by O2 release)Rate of photosynthesisAction spectrum. This graph plots the rate of photosynthesis versus wavelength. The resulting action spectrum resembles the absorption spectrum for chlorophyll a but does not match exactly (see part a). This is partly due to the absorption of light by accessory pigments such as chlorophyll b and carotenoids.(b)
19The action spectrum for photosynthesis Was first demonstrated by Theodor W. Engelmann400500600700Aerobic bacteriaFilamentof algaEngelmann‘s experiment. In 1883, Theodor W. Engelmann illuminated a filamentous alga with light that had been passed through a prism, exposing different segments of the alga to different wavelengths. He used aerobic bacteria, which concentrate near an oxygen source, to determine which segments of the alga were releasing the most O2 and thus photosynthesizing most.Bacteria congregated in greatest numbers around the parts of the alga illuminated with violet-blue or red light. Notice the close match of the bacterial distribution to the action spectrum in part b.(c)Light in the violet-blue and red portions of the spectrum are most effective in driving photosynthesis.CONCLUSION
20Absorption of chlorophylls a and b at various wavelengths in the visible light spectrum
21Pigment Molecules that absorb specific wavelengths of light Chlorophyll absorbs reds & blues and reflects greenXanthophyll absorbs red, blues, greens & reflects yellowCarotenoids reflect orange
22Chlorophyll Green pigment in plants Traps sun’s energy Sunlight energizes electron in chlorophyll
23PHOTOSYNTHESISComes from Greek Word “photo” meaning “Light” and “syntithenai” meaning “to put together”Photosynthesis puts together sugar molecules using water, carbon dioxide, & energy from light.
24Happens in two phases Light-Dependent Reaction Converts light energy into chemical energyLight-Independent ReactionProduces simple sugars (glucose)General Equation6 CO2 + 6 H2O C6H12O6 + 6 O2
25First Phase Requires Light = Light Dependent Reaction Sun’s energy energizes an electron in chlorophyll moleculeElectron is passed to nearby protein molecules in the thylakoid membrane of the chloroplast
26Excitation of Chlorophyll by Light When a pigment absorbs lightIt goes from a ground state to an excited state, which is unstableExcitedstateEnergy of electionHeatPhoton(fluorescence)ChlorophyllmoleculeGrounde–Figure A
27Two PhotosystemsPhotosystem II: Clusters of pigments boost e- by absorbing light w/ wavelength of ~680 nmPhotosystem I: Clusters boost e- by absorbing light w/ wavelength of ~760 nm.Reaction Center: Both PS have it. Energy is passed to a special Chlorophyll a molecule which boosts an e-
28A mechanical analogy for the light reactions MillmakesATPe–PhotonPhotosystem IIPhotosystem INADPHFigure 10.14
29ATP Adenosine Triphosphate Stores energy in high energy bonds between phosphates
30NADPH Made from NADP+; electrons and hydrogen ions Made during light reactionStores high energy electrons for use during light-Independent reaction (Calvin Cycle)
32PART II LIGHT INDEPENDENT REACTION Also called the Calvin Cycle No Light RequiredTakes place in the stroma of the chloroplastTakes carbon dioxide & converts into sugarIt is a cycle because it ends with a chemical used in the first step
33Begins & EndsThe Calvin Cycle begins with the products of the light reaction.(the Calvin Cycle uses ATP & NADPH)CO2 is added and ends in the production of sugar (GLUCOSE)Formula: C6H12O6
34The Calvin cycle Figure 10.18 Input Light 3 CO2 CALVIN CYCLE (G3P)Input(Entering oneat a time)CO23RubiscoShort-lived intermediate3 PPRibulose bisphosphate (RuBP)3-Phosphoglycerate6 P61,3-Bisphoglycerate6 NADPH6 NADPH+Glyceraldehyde-3-phosphate6 ATPATP3 ADPCALVINCYCLE51G3P (a sugar) OutputLightH2OLIGHT REACTIONATPNADPHNADP+ADP[CH2O] (sugar)CALVIN CYCLEFigure 10.18O26 ADPGlucose and other organic compoundsPhase 1: Carbon fixationPhase 3: Regeneration of the CO2 acceptor (RuBP)Phase 2: Reduction
35Chloroplast – Where the Magic Happens! +H2OCO2EnergyATP andNADPH2Which splitswaterLight is AdsorbedByChlorophyllCalvin CycleADPNADPChloroplastUsed Energy and is recycled.O2+C6H12O6Light ReactionDark Reaction6 CO H2O + Light energy C6H12O6 + 6 O2 + 6 H2 O
38How Cells Harvest Chemical Energy Introduction to Cell MetabolismGlycolysisAerobic Cell RespirationAnaerobic Cell Respiration
39BREATHING Breathing and Cell Respiration are related CO2LungsMuscle cells carrying outCO2BloodstreamO2CELLULAR RESPIRATIONSugar + O2 ATP + CO2 + H2O
40Cellular Respiration uses oxygen and glucose to produce Carbon dioxide, water, and ATP.GlucoseOxygen gasCarbon dioxideWaterEnergy
41How efficient is cell respiration? Energy released from glucose banked in ATPEnergy released from glucose (as heat and light)Gasoline energy converted to movement100%About 40%25%Burning glucose in an experiment“Burning” glucose in cellular respirationBurning gasoline in an auto engine
42Reduction and Oxidation OILRIG Oxidation is losing electronsReduction is gaining electronsLoss of hydrogen atomsEnergyGlucoseGain of hydrogen atomsGlucose gives off energy and is oxidized
43Glycolysis Glucose General Outline No Oxygen Anaerobic Oxygen Aerobic Pyruvic AcidTransition ReactionFermentationKrebs CycleETS36 ATP
44GlycolysisWhere? The cytosolWhat? Breaks down glucose to pyruvic acid
46Glycolysis Energy In: 2 ATP Energy Out: 4 ATP NET 2 ATP Steps – A fuel molecule is energized, using ATP.Glucose13StepGlycolysis1Glucose-6-phosphate2Fructose-6-phosphateEnergy In: 2 ATP3Fructose-1,6-diphosphateStep A six-carbon intermediate splits into two three-carbon intermediates.44Glyceraldehyde-3-phosphate (G3P)5Step A redox reaction generates NADH.51,3-Diphosphoglyceric acid (2 molecules)6Steps – ATP and pyruvic acid are produced.3-Phosphoglyceric acid (2 molecules)Energy Out: 4 ATP6972-Phosphoglyceric acid (2 molecules)82-Phosphoglyceric acid (2 molecules)NET 2 ATP9Pyruvic acid(2 molecules per glucose molecule)
47General Outline of Aerobic Respiration GlycolysisTransition ReactionKrebs CycleElectron Transport System
48Transition ReactionEach pyruvic acid molecule is broken down to form CO2 and a two-carbon acetyl group, which enters the Krebs cyclePyruvic AcidAcetyl CoA
49General Outline of Aerobic Respiration GlycolysisTransition ReactionKrebs CycleElectron Transport System
50Krebs CycleWhere? In the MitochondriaWhat? Uses Acetyl Co-A to generate ATP, NADH, FADH2, and CO2.
56ELECTRON TRANSPORT CHAIN Electron Transport SystemProtein complexIntermembrane spaceElectron carrierInner mitochondrial membraneElectron flowMitochondrial matrixELECTRON TRANSPORT CHAINATP SYNTHASEFigure 6.12
57Electron Transport System For each glucose molecule that enters cellular respiration, chemiosmosis produces up to 38 ATP molecules
59FermentationRequires NADH generated by glycolysis.Where do you suppose these reactions take place?Yeast produce carbon dioxide and ethanolMuscle cells produce lactic acidOnly a few ATP are produced per glucose
61Fermentation in the Absence of Oxygen Fermentation When oxygen is not present, fermentation follows glycolysis, regenerating NAD+ needed for glycolysis to continue.Lactic Acid Fermentation In lactic acid fermentation, pyruvate is converted to lactate.
62Each molecule of glucose can generate molecules of ATP in aerobic respiration but only 2 ATP molecules in respiration without oxygen (through glycolysis and fermentation).