ChloroplastChloroplastStructureStructure

How do plants capture light energy ?How do plants capture light energy ?

Energy does workEnergy does workEnergy can move rocks uphill. Energy can move rocks uphill.

The sun’s light energy is used to move H+ The sun’s light energy is used to move H+ from a low to high concentration gradient from a low to high concentration gradient

Stroma

Thylakoid Space

11stst stage of photosynthesis: Light Reactions stage of photosynthesis: Light ReactionsSunlight transfers energy to chlorophyll a

e- are excited and move releasing energy to move H+ to inside of thylakoid

PS 2

Electrons release stored E as they move from one Electrons release stored E as they move from one molecule to another ( PS, ETC) molecule to another ( PS, ETC)

The released e- is to used to create NADPHThe released e- is to used to create NADPH

HH++ HH++HH++

HH++

HH++

HH++

HH++

PS 1

HH++

ee--

NADP+NADP+ HH

HH++

ee--

Inside of Thylakoid

Stroma

PHOTOSYSTEM II W/ Chlorophyll a

ETC

NADPHNADPH

PrimaryPrimaryProductsProducts

of Light Rxnsof Light Rxns

Light ReactionsLight Reactions

Stroma

Thylakoid Space

NADP picks up eNADP picks up e- - and Hand H++

ETC

ATPATPSynthaseSynthase

ChemiosmosisChemiosmosis

HH++ HH++

HH++

HH++HH++

HH++

HH++ HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

ATP SynthaseATP Synthase

Large concentration Large concentration gradient of protons (H+)gradient of protons (H+)

Protons cannot cross the Protons cannot cross the membrane except membrane except through ATP Synthase through ATP Synthase (channel protein)(channel protein)

ATP Synthase harnesses ATP Synthase harnesses flow of protons to form flow of protons to form ATP moleculesATP moleculesADP PAT

P

Lake Mead represents potential energy such as many H+ stored in

the thylakoid

Hoover Dam is the thylakoid

membrane with ATP synthase in it

H+

H+

H+H+

H+

Turbines represent the ATP synthase

ATP

ATP Synthases Harnessing the Flow of ProtonsATP Synthases Harnessing the Flow of Protons

HH++ HH++

HH++

HH++HH++

HH++

HH++ HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

HH++

ADPADP PPATPATPADPADP PPATPATP

ATP SynthaseATP Synthase

What influences the rate of What influences the rate of photosynthesis? photosynthesis?

Independent variable Independent variable

LightLight

Temperature Temperature

Rat

e of

Pho

tosy

nthe

sis

Independent Variable

Review QuestionsReview Questions

1.1. What parts make up an ATP molecule?What parts make up an ATP molecule?

2.2. How can a cell put together ADP and How can a cell put together ADP and another phosphate to form ATP?another phosphate to form ATP?

3.3. How can a cell build up a proton How can a cell build up a proton gradient (a difference in concentrations gradient (a difference in concentrations of protons across a membrane)?of protons across a membrane)?

4.4. Where is the high end of the Where is the high end of the concentration gradient established? concentration gradient established?

5.5. How can a cell energize electrons?How can a cell energize electrons?