WWHHYY do leaves change color in the do leaves change color in the fall?fall? Form a hypothesis about why you think leaves change Form a hypothesis about why you think leaves change

colors.colors.

ANSWER:ANSWER:The same reason bananas The same reason bananas ripen.ripen.

Explanation

Explanation 2

Autotroph vs. Autotroph vs. HeterotrophHeterotroph

AutotrophAutotroph able to make their own foodable to make their own food EX: plants use sun energyEX: plants use sun energy Producers Producers

Photoautotrph – use energy of light to make organic molecules from Photoautotrph – use energy of light to make organic molecules from inorganicinorganic

HeterotrophHeterotroph Obtain energy from food consumedObtain energy from food consumed EX: Humans, leopards, mushroomsEX: Humans, leopards, mushrooms ConsumersConsumers

PhotosynthesisPhotosynthesis

Definition:Definition: Process used to Process used to convert light convert light into sugar from carbon dioxide and water into sugar from carbon dioxide and water Energy in the form of CarbohydratesEnergy in the form of Carbohydrates Produce oxygen as by-productProduce oxygen as by-product

Reactants Products

Animation – Active Art

RequirementsRequirements1.1. SunlightSunlight

2.2. Pigments (chlorophyll)Pigments (chlorophyll)

3.3. ATPATP

4.4. NADPHNADPH

5.5. WaterWater

6.6. Carbon DioxideCarbon Dioxide

1. Sunlight1. Sunlight

SUNLIGHTSUNLIGHT(continued)(continued)

Perceived as “white light”Perceived as “white light” Electromagnetic energy Electromagnetic energy – radiation that travels – radiation that travels

in rhythmic wavesin rhythmic waves WavelengthWavelength – distance between crests of 2 – distance between crests of 2

adjacent wavesadjacent waves Visible spectrum Visible spectrum – radiation your eye sees as – radiation your eye sees as

colorcolor ROYGBIVROYGBIV Absorbed (not seen) or reflected (seen)Absorbed (not seen) or reflected (seen)

Photons = particles that carry light; fixed quantityPhotons = particles that carry light; fixed quantity

Why are plants usually green?

2. ATP 2. ATP

Adenosine TriphosphateAdenosine Triphosphate DefinitionDefinition: Provides cellular energy: Provides cellular energy Made of:Made of:

AdenineAdenine RiboseRibose 3 phosphate groups3 phosphate groups

ATP continuedATP continued ADP – Adenosine ADP – Adenosine DiDiphosphatephosphate

2 phosphates instead of 32 phosphates instead of 3

Break ATP– release energy from bond

ADP + P – energy needed to make ATP

Conversion of ADP to ATPConversion of ADP to ATP

Fully charged “battery”

ATPADP

Animation 2

3. Pigments3. Pigments DefinitionDefinition: : Light absorbing molecules that Light absorbing molecules that

gather the sun’s energygather the sun’s energy EX: Types of PigmentEX: Types of Pigment

Chlorophyll a Chlorophyll a Chlorophyll bChlorophyll b

Found in chloroplastsFound in chloroplasts Reflect green lightReflect green light Absorb blue/violet and redAbsorb blue/violet and red

Carotenoid Carotenoid (yellow-orange)(yellow-orange) CarrotsCarrots Why are Flamingos pink? Why are Flamingos pink? Link

Structure of ChloroplastsStructure of Chloroplasts Trap light (chlorophyll) and transfer energy Trap light (chlorophyll) and transfer energy

to excite electronsto excite electrons Electrons drive photosynthesis to workElectrons drive photosynthesis to work

Light Energy

CO2 + H2O Sugars + O2Stroma (area between disks)

Grana (stack of thylakoids)

Thylakoid (disklike)

Important parts of PlantImportant parts of Plant Mesophyll Mesophyll – green tissue on interior of – green tissue on interior of

leaf where chloroplasts are foundleaf where chloroplasts are found Stomata Stomata – tiny pores where carbon – tiny pores where carbon

dioxide enters and oxygen exitsdioxide enters and oxygen exits ChloroplastChloroplast

Stroma – fluid filled space where dark Stroma – fluid filled space where dark reaction occursreaction occurs

Thylakoid – interconnected membranous Thylakoid – interconnected membranous sac where light reaction occurssac where light reaction occurs

Grana – stack of thylakoidsGrana – stack of thylakoids

4. NADPH4. NADPH Accepts electronsAccepts electrons ““Truck” that carries electrons (e-)Truck” that carries electrons (e-)

High energy electrons (analogy – hot coals)High energy electrons (analogy – hot coals)

NADP+ (Low energy)NADP+ (Low energy) NADPH (High energy)NADPH (High energy)

One way to trap sunlightOne way to trap sunlight Helps build glucose laterHelps build glucose later

NADP + e- (hydrogen ion) NADP + e- (hydrogen ion) NADPH NADPH

NADPH AnalogyNADPH AnalogyHot Coals Need pan

to Carry

Hot Coals: Electrons

As

Pan: ……?

5. Water5. Water

Sunlight energy splits into:Sunlight energy splits into: 2 Hydrogen ions (H+)2 Hydrogen ions (H+)

Helps make ATP and NADPHHelps make ATP and NADPH

1 oxygen1 oxygen Used in release of oxygen gas (OUsed in release of oxygen gas (O22) )

6. Carbon Dioxide6. Carbon Dioxide

Comes from environmentComes from environment Burning of fossil fuelsBurning of fossil fuels Animals/humans releaseAnimals/humans release

Used to make glucoseUsed to make glucose

ADP and ATP reviewADP and ATP review

Matching Game

Requirements of Requirements of PhotosynthesisPhotosynthesis

Seek & SortSeek & Sort

Provides H+ ionsProvides H+ ions Animals release Animals release Absorbs lightAbsorbs light

UV RaysUV Rays Wavelengths Wavelengths Splits waterSplits water

Chlorophyll a & bChlorophyll a & b Receives H+ ions Receives H+ ions

PhotonsPhotons Provides energy Provides energy ROYGBIVROYGBIV

Cellular energy Cellular energy Chloroplast Chloroplast Produces OProduces O22

Photosystem II

HydrogenIon Movement

ATP synthase

ATP FormationPhotosystem IElectron Transport Chain

Stroma

ThylakoidMembrane

InnerThylakoidSpace

Light ReactionsLight Reactions ““Light dependent reactions”Light dependent reactions” Purpose: Purpose: change light energy into chemical change light energy into chemical

energy of ATP and NADPHenergy of ATP and NADPH ATP and NADPH to be used in Calvin CycleATP and NADPH to be used in Calvin Cycle

Requires lightRequires light Occurs in thylakoid membraneOccurs in thylakoid membrane Produces:Produces:

Oxygen (released into air)Oxygen (released into air) ATP ATP NADPHNADPH

Review of Light reactionReview of Light reaction

Review animation

STEPS of Light ReactionSTEPS of Light Reaction1.1. Light absorbedLight absorbed

Pigments/Photosystems (photosystem II occurs 1Pigments/Photosystems (photosystem II occurs 1stst)) Electrons stimulatedElectrons stimulated

2.2. Water is splitWater is split OO22 released as by-product released as by-product H+ ions producedH+ ions produced

3.3. ATP and NADPH formedATP and NADPH formed Produced by electrons in thylakoidProduced by electrons in thylakoid

• Electron transport chain (ETC)Electron transport chain (ETC) Move into dark reactionsMove into dark reactions

SUMMARYLight + water NADPH, ATP, O2

Text book video Review Animation

ChemiosmosisChemiosmosis Drives ATP synthesis using the potential Drives ATP synthesis using the potential

energy of a concentration gradient of energy of a concentration gradient of hydrogen ions across a membranehydrogen ions across a membrane

Photophosphorylation – using light to doPhotophosphorylation – using light to do

Light reactionLight reaction

Dark ReactionsDark Reactions

Other names: Light independent or Calvin Other names: Light independent or Calvin CycleCycle

Purpose: Change COPurpose: Change CO22 into sugar by into sugar by

using ATP & NADPHusing ATP & NADPH ATP & NADPH from light reactionATP & NADPH from light reaction

Does notDoes not need light need light Takes place in Takes place in stromastroma 6 cycles = 1 glucose6 cycles = 1 glucose Sugar used for growth or food storageSugar used for growth or food storage

Overview of PhotosynthesisOverview of Photosynthesis

Light-Dependent Reactions

CalvinCycle

ATP

NADPH

NADP+

ADP + P

Sugars

CO2

CHLOROPLAST

LightH2O

O2

Matching summary game

Impacts on PhotosynthesisImpacts on Photosynthesis LightLight Carbon DioxideCarbon Dioxide TemperatureTemperature WaterWater

Why is deforestation so Why is deforestation so bad?bad?

ExplanationExplanation Deforestation picturesDeforestation pictures

Green house effectGreen house effect

Photosynthesis and the Photosynthesis and the EnvironmentEnvironment

Greenhouse effect – Greenhouse effect – warming of the warming of the atmosphere as a result of CO2, CH4, and other gases atmosphere as a result of CO2, CH4, and other gases that absorb infrared radiation and slow its escape into that absorb infrared radiation and slow its escape into the atmospherethe atmosphere

Global warming – Global warming – slow but steady rise in earth’s slow but steady rise in earth’s surface temperaturesurface temperature