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PhotosynthesiPhotosynthesiss

Energy & Life

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Overview of Overview of PhotosynthesiPhotosynthesi

ss

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AutotrophsAutotrophs

Plants and some Plants and some other types of other types of organisms that organisms that contain the contain the pigment pigment chlorophyllchlorophyll are able to use are able to use light energy from light energy from the sunthe sun to produce to produce chemical bond chemical bond energy in (glucose).energy in (glucose).

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AutotrophsAutotrophs•Autotrophs Autotrophs

include include organismsorganisms that make that make their own foodtheir own food

•Autotrophs Autotrophs can use the can use the sun’s energy sun’s energy directlydirectly

EuglenaEuglena

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HeterotrophsHeterotrophs• Heterotrophs are Heterotrophs are

organisms that organisms that can NOT make can NOT make their own foodtheir own food

• Heterotrophs Heterotrophs can NOT directly can NOT directly use the sun’s use the sun’s energyenergy

• Heterotrophs Heterotrophs must consume must consume food.food.

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EnergyEnergy• Energy Takes Many Energy Takes Many

Forms such as Forms such as light, light, heat, electrical, heat, electrical, chemical, mechanicalchemical, mechanical

• Energy can be Energy can be changed from changed from one one form to anotherform to another

• Energy can be stored Energy can be stored in chemical bonds & in chemical bonds & then released laterthen released later

Candles release energy as HEAT & LIGHTCandles release energy as HEAT & LIGHT

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ATP – Cellular EnergyATP – Cellular Energy• Adenosine TriphosphateAdenosine Triphosphate• Contains two, high-energy Contains two, high-energy

phosphate bondsphosphate bonds• Also contains the nitrogen base Also contains the nitrogen base

adenine & a ribose sugaradenine & a ribose sugar

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ADPADP• Adenosine DiphosphateAdenosine Diphosphate• ATP releases ATP releases energyenergy, a , a free free

phosphate,phosphate, & & ADPADP when cells when cells take energy from ATPtake energy from ATP

One phosphate bond has been removed

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Sugar in ADP & ATPSugar in ADP & ATP

•Called ribose

•Pentose sugar

•Also found on RNA

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Importance of ATPImportance of ATP

Principal Compound Used To Store Energy In Living Organisms

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Releasing Energy From Releasing Energy From ATPATP•ATP is constantly being ATP is constantly being

used and remade by cellsused and remade by cells•ATP provides all of the ATP provides all of the

energy for energy for cell activitiescell activities•The high energy The high energy

phosphate bonds can be phosphate bonds can be BROKENBROKEN to to release release energyenergy

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Releasing Energy From Releasing Energy From ATPATP

• AddingAdding A A Phosphate Phosphate Group To ADP Group To ADP stores Energy in stores Energy in ATPATP

• RemovingRemoving A A Phosphate Phosphate Group From ATP Group From ATP Releases Energy Releases Energy & forms ADP& forms ADP

Loose

Gain

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Cells Using Biochemical Cells Using Biochemical EnergyEnergy

Cells Use ATP For:• Active transport• Movement• Photosynthesis• Protein Synthesis• Cellular

respiration• All other cellular

reactions

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More on ATPMore on ATP• Cells Have Enough ATP Cells Have Enough ATP

To Last For A To Last For A Few Few SecondsSeconds

• ATP must ATP must constantlyconstantly be be mademade

• ATP ATP Transfers Energy Transfers Energy Very WellVery Well

• ATP Is ATP Is NOTNOT Good At Good At Energy StorageEnergy Storage

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GlucoseGlucose•Glucose is a Glucose is a

monosaccharidemonosaccharide

•CC66HH1212OO66

•One Molecule of One Molecule of glucose Stores glucose Stores 90 90 TimesTimes More Chemical More Chemical Energy Than One Energy Than One Molecule of ATPMolecule of ATP

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The Photosynthesis The Photosynthesis EquationEquation

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PigmentsPigments

• In addition to water, carbon dioxide, and light energy, photosynthesis requires Pigments

•Chlorophyll is the primary light-absorbing pigment in autotrophs

•Chlorophyll is found inside the thylakoid membrane in the chloroplasts

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PhotosynthesisPhotosynthesis

•Carbon dioxide (COCarbon dioxide (CO22)) requiring process that uses requiring process that uses light energy (photons) and light energy (photons) and water (Hwater (H22O)O) to produce to produce organic biomolecules organic biomolecules (glucose).(glucose).

• 6CO2 + 6H2O C6H12O6 + 6O2

SUNphotonsphotons

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PlantsPlants• Autotrophs Autotrophs – produce their own – produce their own

food food (glucose)(glucose)• Process called Process called photosynthesisphotosynthesis• Mainly occurs in the leaves:Mainly occurs in the leaves:

a.a.stoma - poresstoma - pores

b.b.mesophyll cellsmesophyll cells

StomaMesophyllCell

Chloroplast

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Stomata (stoma)Stomata (stoma)PoresPores in a plant’s cuticle in a plant’s cuticle

through which through which waterwater and and gasesgases are exchanged are exchanged between the plant and the between the plant and the atmosphere.atmosphere.

Guard CellGuard CellCarbon Dioxide (CO2)

Oxygen (O2)

Found on the underside of Found on the underside of leavesleaves

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Stomata (stoma)Stomata (stoma)PoresPores in a plant’s cuticle in a plant’s cuticle

through which through which waterwater and and gasesgases are exchanged are exchanged between the plant and the between the plant and the atmosphere.atmosphere.

Guard CellGuard CellCarbon Dioxide (CO2)

Oxygen (O2)

Found on the underside of Found on the underside of leavesleaves

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Light and Light and PigmentsPigments

• Energy From The Sun Enters Earth’s Biosphere As Photons

•Photon = Light Energy Unit

• Light Contains A Mixture Of Wavelengths

•Different Wavelengths Have Different Colors

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Light & PigmentsLight & Pigments

•Different pigmentsDifferent pigments absorb absorb different different wavelengthswavelengths of light of light

•Photons of light Photons of light “excite”“excite” electrons in the plant’s electrons in the plant’s pigmentspigments

• Excited electrons carry the Excited electrons carry the absorbed energy which is absorbed energy which is eventually found in eventually found in glucose.glucose.

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Chlorophyll Chlorophyll

•Found in all Found in all plants, Protist, & plants, Protist, & cyanobacteriacyanobacteria•Makes Makes photosynthesis photosynthesis possiblepossible

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The End