Photo synthese
321 mots
2 pages
LA PHOTOSYNTHESE"Un brin de menthe peut restaurer l'air vicié par la flamme d'une bougie"
Flacon utilisé par Prietsley Joseph Prietsley (1770)
LA PHOTOSYNTHESE
Energie physique
Energie chimique
LA PHOTOSYNTHESE
1ère étape Une réaction en 2 étapes
2ème étape
Bilan : 6CO2 + 12H2O lumière C6H12O6 + 6O2 + 6H2O
La chlorophylle
La chlorophylle a absorbe à 430 nm (bleu) et 660 nm (rouge). La chlorophylle b absorbe à 445 nm ( bleu) et 645 nm ( rouge).
LES CHLOROPLASTES
These organelles capture the energy of sunlight in plant cells and some single-celled eucaryotes. (A) Leaf cells in a moss seen in the light microscope, showing the green chloroplasts. (B) An electron micrograph of a chloroplast in a leaf of grass, showing the highly folded system of internal membranes containing the chlorophyll molecules by which light is absorbed. (C) An interpretative drawing of (B). (B, courtesy of Eldon Newcomb.)
© 2002 by Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter.
Electron micrographs of chloroplasts. (A) In a wheat leaf cell, a thin rim of cytoplasmcontaining chloroplasts, the nucleus, and mitochondriasurrounds a large vacuole. (B) A thin section of a single chloroplast, showing the chloroplast envelope, starch granules, and lipid (fat) droplets that have accumulated in the stroma as a result of the biosyntheses occurring there. (C) A high-magnification view of two grana. A granum is a stack of thylakoids. (Courtesy of K. Plaskitt.)
© 2002 by Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter.
© 2002 by Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter.
UN PHOTOSYSTEME
Espace intrathylacoïde
Stroma
Gradients électrochimiques
Réaction initiale de fixation du carbone dans le stroma par la "RUBISCO", ribulose 1,5-bisphosphate carboxylase
Les deux fonctions de la Rubisco