Chemosynthesis differs from photosynthesis primarily in the source of energy used to produce food.
- Energy Source : Photosynthesis uses sunlight as its energy source to convert carbon dioxide and water into glucose (sugar) and oxygen. Chemosynthesis, on the other hand, uses chemical energy derived from the oxidation of inorganic molecules such as hydrogen sulfide or methane, without the need for sunlight
- Location and Organisms : Photosynthesis occurs in plants, algae, and some bacteria in environments where sunlight is available, such as on land or in shallow water. Chemosynthesis is typically carried out by bacteria and archaea in dark environments like deep-sea hydrothermal vents, cold seeps, or hot springs where sunlight does not penetrate
- Chemical Reactions and By-products : Photosynthesis generally follows the formula:
CO2+6H2O→C6H12O6+6O2\text{CO}_2+6\text{H}_2\text{O}\rightarrow \text{C}6\text{H}{12}\text{O}_6+6\text{O}_2CO2+6H2O→C6H12O6+6O2
producing oxygen as a by-product. Chemosynthesis involves reactions such as:
CO2+4H2S+O2→CH2O+4S+3H2O\text{CO}_2+4\text{H}_2\text{S}+\text{O}_2\rightarrow \text{CH}_2\text{O}+4\text{S}+3\text{H}_2\text{O}CO2+4H2S+O2→CH2O+4S+3H2O
producing sulfur and water as by-products instead of oxygen
- Requirement of Chlorophyll : Photosynthesis requires chlorophyll to capture light energy, whereas chemosynthesis does not involve chlorophyll or light capture pigments
In summary, photosynthesis depends on sunlight and chlorophyll to produce glucose and oxygen, supporting most life on Earth's surface, while chemosynthesis uses chemical energy from inorganic molecules to produce glucose and sulfur compounds, supporting life in dark, extreme environments such as deep ocean vents
