Light Dependent Reaction

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Involves capture of light energy for:

add P to ADP to make ATP

Split water into H+ and OH- ions (photolysis)

OIL RIG

Oxidation is loss of ions

Reduction is gain of ions

When chlorophyll absorbs light it excites two electrons in chlorophyll

This causes the electrons to move up energy levels and release from the chlorophyll

They are taking up by an electron carrier

Chlorophyll has lost electrons so is oxidized

Electron carrier has gained electrons (reduced)

electrons pass only photo system 2 to photo system 1 making a ETC

located in the membrane of the thylakoids

This carriers the electron passes through are at slightly decreasing energy levels

Meaning the electrons lose energy at each stage.

This energy is then used to to attach a P to ADP to form ATP for the light independent reaction

Photolysis

The loss of electrons from excitation leaves the chlorophyll short of electrons

It needs to replace these in order to carry on absorbing light

to replace them, light energy splits up molecules of water to make:

protons (4H+)

electrons (4e-)

oxygen (02)

The electrons are taking up by the chlorophyll

The protons are taking up by NADP (electron carrier)

This makes it reduced NADP

which is used in the light independent reaction

The oxygen is either used for respiration or diffuses out as a waste product

The LDR takes place in the thylakoids

Thylakoid membrane provide large surface area for attachment of chlorophyll and and enzymes

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