CHLOROPLASTS

Site of Photosynthesis

Double Membrane

Interior space called the STROMA

Columns of membrane bound sacs

Sacs = Thylakoids

Stacks = Grana

Membrane holding together Thylakoids & Grana is called the LAMELLAE

THYLAKOID

MEMBRANE

THYLAKOID SPACE

or

LUMEN

PIGMENTS ARE IMBEDDED IN THE MEMBRANE IN CLUSTERS CALLED PHOTOSYSTEMS

THE AMOUNT OF ENERGY IN LIGHT IS DETERMINED BY ITS WAVELENGTH THIS ALSO DETERMINES THE COLOUR OF LIGHT

PHYTOL TAIL

ANCHORS PIGMENT INTO THE THYLAKOID MEMBRANE

PORPHRYIN RING

CENTRAL Mg

ABSORBS LIGHT ENERGY AND TRANSFERS IT TO AN ELECTRON

PHOTOSYNTHESIS OVERVIEW

THERE ARE 2 PHOTOSYSTEMS:

PI or P700ACTIVATED BY A PHOTON OF 700nm

PII or P680680nm PHOTON ACTIVATES IT

LIGHT HAS MUTLIPLE ENTRANCE PTS

SYSTEM MUST ALSO BE ‘RELOADED’

ENERGY HAS BEEN TRANSFERRED FROM SOLAR OR RADIANT ENERGY (light) INTO CHEMICAL POTENTIAL ENERGY (PQ)

JUST AS IN THE ETC IN RESPIRATION THE ELECTRONS ARE THEN MOVED FROM ONE PROTEIN TO ANOTHER ALONG THE MEMBRANE

THIS CAUSES H+ TO BE PUMPED INTO THE LUMEN

EVENTUALLY THE ELECTRONS REACH NADPH REDUCTASE – WHICH ATTACHES THE ELECTRONS AND SOME H+ TO NADP+ CREATING NADPH

H+ THAT BUILDS UP IN THE LUMEN CREATE AN ELECTROCHEMICAL GRADIENT.

AS THIS EQUALIZES THE H+ PASS THROUGH ATP Synthase AND CATALYZE ADP + Pi ATP

“Z DIAGRAM”

A

B

“Z DIAGRAM”

A – NON-CYCLIC e- FLOWA Z-PROTEIN SPLITS H20 AND THE ELECTRONS THEN REPLENISH THOSE LOST BY P680 (PHOTOSYSTEM II) AND OXYGEN IS CREATED AS WASTE

CALLED NON-CYCLIC BECAUSE THE ORIGINAL ELECTRONS ARE NOT RETURNED TO P680

B – CYCLIC ELECTRON FLOWSOME LIGHT WILL ONLY ACTIVATE PHOTOSYSTEM I (P700)

THE ELECTRON IS DOES NOT GET USED TO MAKE NADPH BUT IT DOES HELP SYNTHESIZE ATP

INSTEAD IT IS RETURNED TO REPLENISH PHOTOSYSTEM I (P700)

PHOTOSYNTHESIS OVERVIEW

DARK REACTIONS/CALVIN CYCLE

OCCURS IN THE STROMA

CYCLIC PROCESS INVOLVED IN CARBON FIXATION ABSORBING C02 FROM THE AIR AND ATTACHING IT TO ORGANIC MOLECULES

OCCURS IN 3 PHASES:

1.CARBON FIXATION

2.REDUCTION

3.REGENERATION OF RuBP

C-FIXATION

RUBSICO

REDUCTION

REGENERATION

FATE OF G3PMADE INTO GLUCOSE BY A SERIES OF ENZYMES

GLUCOSE CAN THEN BE CONVERTED TO:

CELLULOSE (CELL WALLS)

STARCH (STORAGE)

USED IN CELL RESPIRATION