Photosynthesis is the fundamental basis of competitive success in green plants and the principal organ of photosynthesis in higher plants is the leaf.
It is the process in which plants utilize carbon dioxide and water as raw material in the presence of light and chlorophyll convert them into glucose (carbohydrates) and release oxygen as a byproduct.
Leaves provide an excellent demonstration of this structure–function relationship. While some leaves may be modiﬁed for special purposes (for example, tendrils, spines, and ﬂoral parts), the primary function of leaves remains photosynthesis.
In order to absorb light efﬁciently, a typical leaf presents a large surface area at approximately right angles to the incoming sunlight. From this perspective, the leaf may be viewed as a photosynthetic machine—superbly engineered to carry out photosynthesis efﬁciently in an extremely hostile environment.
Photosynthes is occurs not only in eukaryotic organisms such as green plants and green algae but also in prokaryotic organisms such as cyanobacteria and certain groups of bacteria.
Chloroplast is the site
In higher plants and green algae the reactions of photosynthesis occur in the chloroplast, which is, quite simply, an incredible thermodynamic machine. The chloroplast traps the radiant energy of sunlight and conserves some of it in a stable chemical form.
The reactions that accomplish these energy transformations are identiﬁed as the light-dependent reactions of photosynthesis. Energy generated by the light-dependent reactions is subsequently used to reduce inorganic carbon dioxide to organic carbon in the form of sugars. Both the carbon and the energy conserved in those sugars are then used to build the order and structure that distinguishes living organisms from their inorganic surroundings.