PhotosynthesisPhotosynthesis

Stages of PhotosynthesisStages of Photosynthesis

TEKSTEKS

9B Compare the transfer of energy from 9B Compare the transfer of energy from one type of molecule to the next in one type of molecule to the next in respiration and photosynthesisrespiration and photosynthesis

ChloroplastsChloroplasts

Thylakoid membraneThylakoid membrane GranaGrana StromaStroma

Two StagesTwo Stages

Light Dependent ReactionsLight Dependent Reactions Convert sunlight to ATP energyConvert sunlight to ATP energy Occurs on thylakoid membraneOccurs on thylakoid membrane

Light Independent ReactionsLight Independent Reactions Uses ATP to make glucoseUses ATP to make glucose Occurs in stromaOccurs in stroma

Light Dependent Light Dependent ReactionsReactions

Photochemical ReactionsPhotochemical Reactions Non-cyclic Electron FlowNon-cyclic Electron Flow ChemiosmosisChemiosmosis

Light Dependent Light Dependent ReactionsReactions

Photochemical ReactionsPhotochemical Reactions Light energy knocks Light energy knocks

electron off chorophyll in electron off chorophyll in photosystems I and IIphotosystems I and II

Light Dependent ReactionsLight Dependent ReactionsNon-cyclic Electron FlowNon-cyclic Electron Flow

11stst stage stage photosystem I passes 2 electrons to NADPphotosystem I passes 2 electrons to NADP++

Photo I now short 2 electronsPhoto I now short 2 electrons

22ndnd stage stage Photosystem II passes 2 electrons to ETC in Photosystem II passes 2 electrons to ETC in

thylakoid membranethylakoid membrane H protons pumped across membraneH protons pumped across membrane Electrons given to Photo I at end of ETCElectrons given to Photo I at end of ETC Now Photo II short 2 electronsNow Photo II short 2 electrons

Light Dependent Light Dependent ReactionsReactions

Non-cyclic Electron Flow, cont..Non-cyclic Electron Flow, cont..33rdrd stage-photolysis stage-photolysis 2 electrons to photo II2 electrons to photo II 2 H protons pumped to inside of grana2 H protons pumped to inside of grana Oxygen leaves plant as wasteOxygen leaves plant as waste

Net effect: Net effect: NADPH + H producedNADPH + H produced HH+ + added to granaadded to granaOxygen released as wasteOxygen released as waste

Light Dependent Light Dependent ReactionsReactions

ChemiosmosisChemiosmosis HH++ flows back through membrane via ATP flows back through membrane via ATP

synthetasesynthetase ATP producedATP produced

Light Dependent Light Dependent ReactionsReactions

Products:Products: OxygenOxygen NADPH + HNADPH + H ATPATP

LDR

Light Independent Light Independent ReactionsReactions COCO22 + H + H++ + ATP used to make glucose + ATP used to make glucose

LIR

Factors Affecting Factors Affecting PhotosynthesisPhotosynthesis

TEKSTEKS

9B Compare the transfer of energy from 9B Compare the transfer of energy from one type of molecule to the next in one type of molecule to the next in respiration and photosynthesisrespiration and photosynthesis

Light IntensityLight Intensity

What effect does What effect does it have?it have? Rate increases Rate increases

then levels offthen levels off

Why?Why? More reactants More reactants

than enzymes… than enzymes… can’t keep upcan’t keep up

TemperatureTemperature

What effect does it What effect does it have?have? Increases then Increases then

decreasesdecreases Why?Why?

Molecules move Molecules move faster; therefore, more faster; therefore, more reactionsreactions

Enzymes denature at Enzymes denature at high temperatureshigh temperatures

Carbon DioxideCarbon Dioxide

What effect does it What effect does it have?have? Low conc. - slowsLow conc. - slows High conc. - slowsHigh conc. - slows

Why?Why? Low amounts of Low amounts of

reactants slow ratereactants slow rate

WaterWater

What effect does it have?What effect does it have? Little water slows rateLittle water slows rate

Why?Why? Stomata closeStomata close

OxygenOxygen

What effect does it have?What effect does it have? Slows rateSlows rate

Why?Why? Destroys pigmentsDestroys pigments PhotorespirationPhotorespiration

CAMCAM

Used by desert plantsUsed by desert plants Close stomata during dayClose stomata during day COCO22 gathered at night and stored gathered at night and stored

Rate of photosynthesis is lowRate of photosynthesis is low