Energy CarriersEnergy Carriers

Energy CarriersEnergy Carriers

In Photosynthesis, energy in sunlight is In Photosynthesis, energy in sunlight is used to make food. used to make food.

In Respiration, food is broken down to In Respiration, food is broken down to release energy.release energy.

Molecules ADP, NADMolecules ADP, NAD++ and NADP and NADP++ trap trap and transfer this energy and transfer this energy

ADPADP ADP = ADP = AAdenosine denosine DDiiPPhosphatehosphate This molecule is found in ALL living cells. This molecule is found in ALL living cells. Adenine—Ribose—Phosphate ~ PhosphateAdenine—Ribose—Phosphate ~ Phosphate

Unstable bondUnstable bond ADP is a low energy moleculeADP is a low energy molecule

ATPATP ATP = ATP = AAdenosine denosine TTririPPhosphatehosphate Add another phosphate to ADP = ATPAdd another phosphate to ADP = ATPAdenine —Ribose—Phosphate~Phosphate~PhosphateAdenine —Ribose—Phosphate~Phosphate~Phosphate

Extra energy in unstable bondExtra energy in unstable bond

Phosphorylation=adding a phosphate groupPhosphorylation=adding a phosphate group ADP + energy + P ADP + energy + P ATP + Water ATP + Water ATP is an Energy rich compoundATP is an Energy rich compound

ATPATP ATP stores energy, not for long thoughATP stores energy, not for long though

It can be moved around inside a cellIt can be moved around inside a cell

When ATP breaks down to ADP it releases energyWhen ATP breaks down to ADP it releases energy

Energy released is used to carry out most reactions in the Energy released is used to carry out most reactions in the cells. cells.

ATP + Water ATP + Water ADP + P + energy ADP + P + energy

Cells release energy from ATP 10 million times per secondCells release energy from ATP 10 million times per second

ATP and ADP

NADPNADP++

NADPNADP+ + = Nicotinamide Adenine Dinucleotide Phosphate= Nicotinamide Adenine Dinucleotide Phosphate Is a low energy molecule involved in Is a low energy molecule involved in PhotosynthesisPhotosynthesis NADPNADP+ + accepts a Hydrogen proton+ 2 electrons = NADPHaccepts a Hydrogen proton+ 2 electrons = NADPH

NADPNADP+ + + 2 electrons + H+ 2 electrons + H+ + NADPH NADPH

(Low energy) (High energy) (High energy)(Low energy) (High energy) (High energy)

The Addition of Electrons to a molecule = ReductionThe Addition of Electrons to a molecule = Reduction NADPNADP+ + is said to be reduced to NADPHis said to be reduced to NADPH

NADPHNADPH NADPH is a very High energy NADPH is a very High energy

molecule.molecule. It is an electron carrierIt is an electron carrier Energy it carries is used in Energy it carries is used in

photosynthesisphotosynthesis When it breaks down it releases When it breaks down it releases

2 high-energy electrons & a 2 high-energy electrons & a hydrogen ionhydrogen ion

NADPH NADPH NADP NADP++ + 2 electrons + H + 2 electrons + H++

(High Energy) (Low Energy) (High Energy)(High Energy) (Low Energy) (High Energy)

ATP Vs NADPHATP Vs NADPH

NADPNADP+ + Vs NAD Vs NAD++

NADNAD++ = Respiration = Respiration NADNADPP++ = = PPhotosynthesishotosynthesis

NADNAD++ is a low energy molecule just like NADP is a low energy molecule just like NADP++ and changes to the high-energy molecule NADH and changes to the high-energy molecule NADH just like NADPHjust like NADPH

PhotosynthesisPhotosynthesis

Plants making their own foodPlants making their own food

Role of PhotosynthesisRole of Photosynthesis Plants use it to make foodPlants use it to make food Animals get their food from plantsAnimals get their food from plants It produces oxygen which is needed to release It produces oxygen which is needed to release

energy in respirationenergy in respiration It is responsible for forming fossil fuelsIt is responsible for forming fossil fuels It removes carbon dioxide from the airIt removes carbon dioxide from the air

Photosynthesis requires:Photosynthesis requires:

carbon dioxide, carbon dioxide, water, water, light energy, light energy, chlorophyll. chlorophyll.

Photosynthesis producesPhotosynthesis produces

glucose glucose waste oxygenwaste oxygen

Photosynthesis convertsPhotosynthesis converts

light energylight energy

chemical energychemical energy

Stages in PhotosynthesisStages in Photosynthesis Light is absorbedLight is absorbed

- - By Chlorophyll in ChloroplastBy Chlorophyll in Chloroplast Water is splitWater is split

- 2H- 2H22O O 4H 4H++ +4e +4e-- + O + O22

Products are producedProducts are produced- Oxygen, hydrogen ion & electrons- Oxygen, hydrogen ion & electrons

Light energises electronsLight energises electrons-sunlight energises electrons through chlorophyll-sunlight energises electrons through chlorophyll

Glucose is formedGlucose is formed- CO- CO22 + H + H++ + E + E- - C C66HH1212OO66

Sources of Light COSources of Light CO22 & H & H22OO

LightLight SunSun Artificial bulbsArtificial bulbs

Carbon DioxideCarbon Dioxide Animals respiringAnimals respiring Burning of fossil fuelsBurning of fossil fuels

WaterWater In soil due to rain or nearby rivers & lakesIn soil due to rain or nearby rivers & lakes

2 stages of Photosynthesis2 stages of Photosynthesis

Photosynthesis

Light Stage Dark Stage

Light StageLight Stage

This takes place in the grana of the chloroplastThis takes place in the grana of the chloroplast It makes energy for converting ADP + P into It makes energy for converting ADP + P into

ATPATP It makes hydrogen ions from the splitting of It makes hydrogen ions from the splitting of

water to use in the dark stage of water to use in the dark stage of photosynthesisphotosynthesis

Light stageLight stage

Light Stage

PhosphorylationMaking ATP

PhotolysisSplitting water

PhotolysisPhotolysisThe splitting of waterThe splitting of water

Water2H20

Hydrogen ions4H+

Electrons4E-

Oxygen02

Used to convert NADPTo

NADPH

By productExcreted through leafGo back to chlorophyll

Water Splitting EquationWater Splitting Equation

2H2H22O O 4H 4H++ +4e +4e-- + O + O22

Light

PhosphorylationPhosphorylationMaking ATP and NADPHMaking ATP and NADPH

Where do plants get their energy Where do plants get their energy from?from?- Sun Light- Sun Light

There are 7 different colours in There are 7 different colours in white light, the plant can only white light, the plant can only absorb these if it has a pigment.absorb these if it has a pigment.

The most important pigment is The most important pigment is Chlorophyll because it sits next to Chlorophyll because it sits next to an electron acceptor. an electron acceptor.

The electron acceptor takes the The electron acceptor takes the energy from the pigments and adds energy from the pigments and adds it into electrons.it into electrons.

Chloroplast Pigments – In GranaChloroplast Pigments – In Grana

Light energy absorbed

Pigments

Energy Passed on

Energised electrons passed on

Electron acceptor

Electron Flow Pathways to make Electron Flow Pathways to make ATP & NADPHATP & NADPH

2 Different Pathways2 Different Pathways1.1. Cyclic PhotoPhosphorylationCyclic PhotoPhosphorylation

((circle) (light) (adding a phosphate)circle) (light) (adding a phosphate)

2.2. Non-Cyclic PhotoPhosporylationNon-Cyclic PhotoPhosporylation

Electron Pathway 1:Electron Pathway 1:Cyclic PhotophosporylationCyclic Photophosporylation

Light energy

absorbed

ADP + P

ATP + Water

Electron flow that looses energy as it

goes around

ADP traps this energy by adding another phosphateElectron Acceptors

E-

E- E-

E- E-

Chlorophyll

Energy Energy Energy

Energy Energy

Energy

Electron Pathway 1:Electron Pathway 1:Cyclic PhotoPhosphorylationCyclic PhotoPhosphorylation

High energy electrons travel around a series of High energy electrons travel around a series of electron acceptors & back again to chlorophyllelectron acceptors & back again to chlorophyll

As they move around they loose energyAs they move around they loose energy This energy is trapped by ADP and a This energy is trapped by ADP and a

phosphate within their bonds.phosphate within their bonds. This forms ATP and water.This forms ATP and water. ADP + energy + Phosphate ADP + energy + Phosphate ATP + water ATP + water

Electron Pathway 2:Electron Pathway 2:Non -Cyclic PhotophosporylationNon -Cyclic Photophosporylation

Light energy

absorbed

2H2O

ATP + Water

Electron Acceptors

2E- 2E-

2E-

O2

4H+

4E-

ADP + P

2E-

NADP+

NADP- NADPH

Chlorophyll

2E-

Light

+ H+

Electron Pathway 2:Electron Pathway 2:Non-Cyclic PhotoPhosphorylationNon-Cyclic PhotoPhosphorylation

2 high energy electrons passed along at a time 2 high energy electrons passed along at a time through a series of electron acceptorsthrough a series of electron acceptors

They loose energy as they pass from acceptor They loose energy as they pass from acceptor to acceptor, this energy is used to make ATPto acceptor, this energy is used to make ATP

At the end 2 electrons combine with NADPAt the end 2 electrons combine with NADP+ + to to form NADPform NADP--..

Water is split using light energy, 2 electrons Water is split using light energy, 2 electrons return to chlorophyll while the protons attach return to chlorophyll while the protons attach to NADPto NADP-- to form NADPH to form NADPH

Products of Light StageProducts of Light Stage

OxygenOxygen ATPATP NADPHNADPH

Dark StageDark Stage

This is also known as the Calvin cycleThis is also known as the Calvin cycle It takes place in the stroma of the chloroplastIt takes place in the stroma of the chloroplast It uses energy got from breaking down It uses energy got from breaking down

ATP into ADP + PATP into ADP + P

It uses hydrogen ions and electrons got from It uses hydrogen ions and electrons got from breaking down breaking down NADPH into NADPNADPH into NADP+ + ++ 2 electrons + H2 electrons + H++

Dark Stage Calvin CycleDark Stage Calvin Cycle

6CO2

Oxygen atoms are removed

12 Hydrogen ionsare added

Electrons areadded

Glucose is formedC6H1206

Dark Stage Calvin CycleDark Stage Calvin Cycle

Carbon Dioxide Glucose (C6H12O6)

NADP+NADPH

ATP ADP + P

Main events in photosynthesisMain events in photosynthesis Light energy is absorbed by chlorophyllLight energy is absorbed by chlorophyll Water is split Water is split The electrons are passed to chlorophyllThe electrons are passed to chlorophyll The protons are stored in the chloroplastsThe protons are stored in the chloroplasts The oxygen is releasedThe oxygen is released Sunlight transfers energy to electronsSunlight transfers energy to electrons The high energy electrons, stored protons( the The high energy electrons, stored protons( the

hydrogen ions) and carbon dioxide are used to hydrogen ions) and carbon dioxide are used to make glucosemake glucose

Light

Chlorophyll

Electron Deficient ChlorophyllHigh Energy

Electrons

Water Protons + electrons + oxygen

Proton Pool

ADP

ATP

NADP+ NADPH

Released