Autotrophic nutrition

AUTOTROPHIC NUTRITION

Organisms which utilise carbon dioxide as their sole source of carbon for the formation of organic food by the process of photosynthesis are called autotrophs (self nourishing).
The type of nutrition carried out by autotrophs is termed as autotrophic nutrition.
In this type of nutrition, the living organisms manufacture their own organic food from simple inorganic raw materials.
The green plants exhibit autotrophic mode of nutrition and hence are called the autotrophs.
The autotrophs require external energy source for the manufacture of organic substances.
Green plants obtain energy from sunlight and therefore are called photoautotrophs.
The process of synthesizing food in plant is called photosynthesis.

Photosynthesis:

This term was coined by Charles Reid Barnes in 1883.
Plants are producers, and producers make their own food.
This food is in the form of a sugar (often glucose).
Sugars are made during a process called photosynthesis from carbon dioxide and water.
The end products, organic compounds, are made from the simple inorganic compounds- water and carbon dioxide.

The two raw materials required for photosynthesis are acquired by different means.
Carbon dioxide is absorbed by the leaves while water is obtained by the roots from the soil.
In order for the reaction to take place, energy comes from light (usually the sun) and is stored within the sugar which is an energy-rich molecule.
The reaction that takes place can be written as:

The process of using the energy of sunlight to convert water and carbon dioxide into carbohydrates (starch) and oxygen is called photosynthesis.

Conditions Necessary for Photosynthesis: