Photosynthesis in Higher Plants

Photosynthesis is a physicochemical process by which plants use light energy for the synthesis of organic compounds. Photosynthesis is important as it is the primary source of all food on Earth and is also responsible for the release of oxygen into the atmosphere by green plants. Photosynthesis takes place only in the green parts of the plants, mainly the leaves.

Within the leaves, the mesophyll cells consist of a large number of chloroplasts that carry out photosynthesis. Photosynthesis has two stages: the light reaction and the carbon-fixing reaction. Within the chloroplasts, the light reaction takes place in the membranes, while the chemosynthetic pathway occurs in the stroma. There are 4 pigments involved in photosynthesis: Chlorophyll a, Chlorophyll b, Xanthophylls, and Carotenoids.

Also Read: Photosynthetic Pigments

Photosynthesis in higher plants is an important biological process for energy production. Chlorophyll pigments capture sunlight, initiating the light-dependent reactions in chloroplasts. Water molecules are split, release oxygen, and generate ATP and NADPH. In the subsequent Calvin Cycle, carbon dioxide is assimilated, producing glucose as the end product essential for plant growth and metabolism.

C3 plants use the Calvin Cycle for photosynthesis in mesophyll cells, while C4 plants separate carbon fixation and the Calvin Cycle between mesophyll and bundle sheath cells, reducing photorespiration. C4 plants are adapted to hot and arid conditions with improved water-use efficiency.