Green Plants– Source of Photosynthesis
Photosynthesis is a process used by plants, primarily takes place in plant leaves, and often occurs in stems, etc. The parts of a typical leaf include the upper and lower epidermis, the mesophyll, the vascular bundles, and the stomata. Since upper and lower epidermal cells do not have chloroplasts, photosynthesis does not occur there. Chloroplasts are abundant in mesophyll cells of leaf and is the site for photosynthesis. The stomata are holes, which occur primarily in the lower epidermis and are for exchange for gases: they let CO2 in and O2 out, a process called transpiration. It is a typical process used by plants and other organisms to absorb the sun's energy for splitting water's hydrogen from oxygen. Hydrogen combines with carbon dioxide to form glucose and release oxygen.
Green plants are extremely significant because they are the only organisms with the biochemical ability to "make" chemically complex organic food for themselves, starting with simple inorganic substances.
The green plants, also called the producers, trap the solar energy and convert it into chemical energy of the food. Food is required to provide energy. The compound that can be easily broken down in order to yield energy is glucose.
Thus, the plants synthesize glucose, which is stored in the form of starch by a process called photosynthesis. 'Photo' means 'light' and 'synthesis' means 'to build', thus 'photosynthesis' means 'building up by light'.
The plants use the energy in sunlight to prepare food from carbon dioxide and water in the presence of chlorophyll. Chlorophyll is present in the green colored bodies called 'chloroplasts' inside the plant cells. In fact, the leaves of a plant are green because they contain tiny green colored bodies called chloroplasts (which contain chlorophyll).
The process by which living plant cells, containing chlorophyll, produce food substances (glucose and starch), from carbon dioxide and water, by using light energy is called photosynthesis. They release oxygen as a waste product in this process. Photosynthesis is the only biological process, which releases oxygen into the atmosphere. The oxygen supports all life on earth.
Photosynthesis takes place primarily in plant leaves, and little to none occurs in stems, etc. The parts of a typical leaf include the upper and lower epidermis, the mesophyll, the vascular bundle(s) (veins), and the stomata. The upper and lower epidermal cells do not have chloroplasts, thus photosynthesis does not occur there.
The stomata are holes, which occur primarily in the lower epidermis and are for air exchange: they let CO2 in and O2 out. The vascular bundles or veins in a leaf are part of the plant’s transportation system, moving water and nutrients around the plant as needed. The mesophyll cells have chloroplasts and this is where photosynthesis occurs.