Photosynthesis is a complex process used by many plants and bacteria to build carbohydrates from carbon dioxide and water, using energy derived from light. Photosynthesis is the process of converting light energy to chemical energy and storing it in the bonds of sugar. Photosynthesis is the key initial step in the growth of biomass. In the process oxygen and water are released. Increased levels of carbon dioxide can increase net photosynthesis in some plants. Plants create a very important reservoir for carbon dioxide. From energy produced by sunlight, the leaves combine carbon dioxide from the air and water from the soil to produce carbohydrates. Oxygen is released in the process. Carbohydrates plus fats and proteins are the plant foods necessary for growth and respiration of the tree.
Plants are the only photosynthetic organisms to have leaves (and not all plants have leaves). A leaf may be viewed as a solar collector crammed full of photosynthetic cells. Plants capture light using the pigment chlorophyll, which gives them their green color. This is contained in organelles (compartments within the cells) called chloroplasts. Chlorophyll or closely-related pigments (substances that color the plant) are essential to the photosynthetic process. The cells in the interior tissues of a leaf, called the mesophyll, contain about half a million chloroplasts for every square millimetre of leaf. The surface of the leaf is uniformly coated with a water-resistant, waxy cuticle, that protects the leaf from excessive absorption of light and evaporation of water. The transparent, colourless epidermis layer allows light to pass through to the palisade mesophyll cells where most of the photosynthesis takes place.
The chlorophyll molecule is the site of "photosynthesis", the process by which the energy of the sun is converted firstly into the energy of sugars and other carbohydrates. These in turn supply virtually all of the energy needed by the plant and animal world. Chlorophyll is essential in the transformation of light energy to chemical energy in photosynthesis. Plants use chlorophyll to convert the energy of sunlight to food in the process known as photosynthesis.