Photosynthesis

Front 1

Photosynthesis

Back 1

Process which converts light energy into chemical energy, to synthesise organic molecules.
It happens in the chloroplasts

Front 2

Autotroph

Back 2

Organisms that use light energy or chemical energy and inorganic molecules to synthesise complex organic molecules

Front 3

Heterotroph

Back 3

Organisms that ingest and digest complex organic molecules, releasing the chemical potential energy stored in them

Front 4

Photosynthetic Pigment

Back 4

are molecules that absorb light energy, each pigment absorbs a range of wavelengths in the visible region and has its own distinct peak of absorbtion.

Front 5

Chloroplasts - Structure

Back 5

Disk shaped, 2-10um long, double membrane, inter membranal space.
fluid filled matrix, light-indepedent reactions occur here
Grana are stacks of thylakoid membranes, site of light-dependent reactions

Front 6

Chloroplasts - Function, adapted

Back 6

Thylakoid membranes hold photosystems in place.
Stroma contains enymes for catalysing the independant reactions.
Thylakoids are surronded by the Stroma so the products are available

Front 7

Chlorophylls

Back 7

Two forms;
chlorophyll a - p680 and is found in photosystem II
chlorophyll b - p700 and is found in photosystem I

Front 8

Accessory Pigments

Back 8

Carotene and xanthophyll, reflect yellow and oragne light.

Front 9

Light-dependent stage
Cyclic photophosphorylation

Back 9

Photosystem I
When a light photon hits the chlorophyll b pigment, it excites a pair of electrons and raises ithem to a higher energy level.
the electrons are passed to an electron acceptor and back to the chlorophyll b molecule.
ATP is made and is then used in non-cyclic.

Front 10

Photophosphorylation

Back 10

is the making of ATP from ADP and inorganic phosphate, in the presence of light.

Front 11

Electron carriers

Back 11

are molecules that transfer electrons

Front 12

Electron Acceptors

Back 12

are chemicals taht accept electrons from abother compound. They are reduced whilst acting as an oxidising agent

Front 13

Light-dependent stage
Non-cyclic photophosphorylation

Back 13

Light photons hit both photosystem I and II and a pair of electrons leave both.
The electrons from PSII move through electron acceptors and replace the electrons lost from PSI.
Photolysis of water occurs at PSII and the electrons released replaces those lost from PSII.
The electons from PSI move along a series of electron carriers and team up with the hydrogen ions released from photolysis and reduces NADP (with the help of NADP reductase)