photosynthesis

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PHOTOSYNTHESIS

(Part 1)

The Basic Facts

• It is the conversion of light energy into chemical potential energy.

• The energy is stored in organic molecules (e.g. ATP and glucose)

• Carbon dioxide is reduced to produce carbohydrate

• So, it needs a supply of electrons hydrogens and energy!

Light dependent stage

(on thylakoid membranes)

• The aim is to produce a supply of

ATP (energy) and electrons that can be used to reduce carbon dioxide.

• The electrons are carried by NADP

(called reduced NADP or NADPH when it is carrying electrons).

• Oxygen is released as a waste product.

water

Or put a different way…

NADPH

NADP light dependent reaction

oxygen

ADP + P

ATP

This is a blank slide for Mr King to do his own drawing on

Photolysis

• Using light energy to split water into electrons, hydrogen ions and water.

• H

2

O

H + + e + O

2

• Replacing the electrons and hydrogen ions now carried by NADPH

summary

• Chlorophyll absorbs light energy and its electrons are ‘excited’

• ‘excited’ electrons pass through a series of carriers releasing energy to generate ATP from ADP and P

(photophosphorylation)

• Electrons are picked up by NADP

• Light energy splits water and the electrons are used to replace missing electrons in chlorophyll

• This all happens on membranes.

The light dependent reaction takes place on the...

This is so that...

The reaction needs ...., ...., .... and ....

The reaction produces .... and ...

.... is also produced.

The ... and ...pass into the ... for the second stage in photosynthesis.

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