Photosynthesis is a method of transforming light energy into chemical energy by phototrophs, which is later used to fuel cell functions. Chemical energy is stored in the form of sugars, which are generated from carbon dioxide and water.
- Algae also use photosynthesis to turn solar energy into chemical energy.
- As a by-product, oxygen is released and light is regarded as a major factor in completing the photosynthesis process.
- When plants use light energy to turn carbon dioxide and water into glucose and oxygen, photosynthesis happens.
- Microscopic cellular organelles known as chloroplasts are available in leaves.
- There is a green-coloured pigment called chlorophyll in each chloroplast.
- Chlorophyll molecules absorb light, while carbon dioxide and oxygen enter via the small pores of stomata found in the epidermis of the leaves.
- Sugars, including glucose and fructose, are another by-product of photosynthesis.
- The roots, stems, leaves, fruits, flowers and seeds are then absorbed by these sugars.
- In other words, plants use these sugars as a source of energy, which allows them to grow.
- To form more complex carbohydrates such as cellulose and starch, these sugar molecules then bind with each other.
- Cellulose is known as the structural material used in the walls of plant cells.
Types of Photosynthesis
There are two different types of photosynthesis:
Oxygenic photosynthesis is more common in plants, algae and cyanobacteria. During this process, electrons are transferred from water to carbon dioxide by light energy, to produce energy. During this transfer of electrons, carbon dioxide is reduced while water is oxidized, and oxygen is produced along with carbohydrates. During this process, plants take in carbon dioxide and expel oxygen into the atmosphere. This process can be represented by the equation,
6CO2 + 12H2O + LIGHT ENERGY → C6H12O6 + 6O2 + 6H2O
This type of photosynthesis is usually seen in certain bacteria, such as green sulphur bacteria and purple bacteria which dwell in various aquatic habitats. Oxygen is not produced during the process. The anoxygenic photosynthesis can be represented by the equation:
CO2 + 2H2A + LIGHT ENERGY → [CH2O] + 2A + H2O