Autotrophic nutrition is a mode of nutrition in which organisms can synthesize their own organic molecules (such as carbohydrates) from inorganic sources. Autotrophs, the organisms that exhibit autotrophic nutrition, have the ability to produce their own food using energy from sunlight (photosynthesis) or certain inorganic chemicals (chemosynthesis).
There are two primary types of autotrophic nutrition:
Photosynthesis:
Photosynthetic autotrophs, such as plants, algae, and some bacteria, use sunlight as a source of energy to convert carbon dioxide and water into glucose (a form of carbohydrate). This process takes place in the chloroplasts of plant cells and involves the green pigment chlorophyll. The overall chemical equation for photosynthesis is:
6CO2​+6H2​O+ light energy→C6​H12​O6​+6O2​
​Chemosynthesis:
Chemosynthetic autotrophs, found in certain bacteria and archaea, utilize energy derived from chemical reactions to synthesize organic molecules. Unlike photosynthesis, which relies on sunlight, chemosynthesis is driven by the oxidation of inorganic compounds, such as hydrogen sulfide (Hâ‚‚S) or methane (CHâ‚„). Chemosynthetic organisms are often found in environments with limited sunlight, such as deep-sea hydrothermal vents. The overall chemical equation for chemosynthesis varies depending on the specific reactions involved.
Autotrophic nutrition is crucial for the sustenance of ecosystems, as autotrophs form the base of the food chain by producing organic compounds that heterotrophs (organisms that cannot produce their own food) rely on for energy. Plants, algae, and some bacteria play key roles in supporting life on Earth through their ability to perform autotrophic nutrition.