PHOTOSYNTHESIS -STAGES

=Photosynthesis= ''' Carbon Dioxide + Water → Glucose + Oxygen''' ''' 6CO~2~ + 6H~2~O → C~6~H~12~O~6 ~ + 6O~2~''' [image:http://i.imgur.com/QzWgxII.png?1] Photosynthesis involves a series of reactions that convert light (radiant) energy in chemical potential energy in the form of glucose. The process begins when chlorophyll a green pigment absorbs light. Chrolophyll is found embedded within the internal folds of the chloroplasts inner membrane. These membrane folds form disc-like structures called '''thylakoids'''. These discs are arranged into stacks called '''grana''' which are connected to one another and the inner membrane by membranous extensions called '''lamella'''. The clear fluid inside the chloroplast is known as the '''stroma'''. Photosynthesis actually involves a series of chemical reaction. They key stages have been outlined below. ==The Light-Dependent Phase:== '''Water → Oxygen + Hydrogen + ATP''' Photosynthesis begins when chlorophyll in the thylakoid membrane absorbs light energy. This energy is ultimately used to split water into oxygen & hydrogen and to produce a few ATP molecules. The hydrogens produced are picked up by a special carrier molecule known as NADPH. The folded structure of the thylakoid membranes provides a larger surface area on which the light-dependent reaction can occur. ==Light-Independent Phase:== '''Hydrogen + Carbon Dioxide → Glucose''' This phase is also known as the '''Calvin Cylce''' or the '''dark phase''' because it doesn't require light. NADPH carries the hydrogens produced during the light-dependant phase into the stroma. Here the hydrogen’s are combined with CO~2~ to make glucose (a carbohydrate). This can also be referred to as '''carbon fixation''' or the '''synthesis phase''' because carbon dioxide gas is used to make (synthesise) to glucose (an organic material).