nutrition is the process of taking food by an organism and its utilisation by the body.

Mode of nutrition-

the mode of nutrition is called heterotrophic nutrition.On the basis of different mode of nutrition, organisms are categorized into two major type-
1.autotrophics(auto-self ,trophos -nourishment) – it is the mode of nutrition in which organisms make their own food from simple substance (eg.co2 and H2o) by the process of photosynthesis.
2.heterotrophs( heteros-other)- organisms which cannot prepare their own food and take food from green plants and animals are called heterotrophs and


(Photo=light , synthesis=to combine)-photosynthesis is the process of synthesis of food (glucose) from carbon dioxide and water, using solar energy by chlorophyll pigments.
– during the process oxygen is released. Glucose ultimately converted into starch.

-The process of photosynthesis take place in green leaves, there fore leaves are referred to us the “food factories of plants”.

Requirements in photosynthesis

1.co2=co2 is taken from air through the tiny pores present on the surface of leaves called stomata.
2.water=water is absorbed through the roots of plants and transported to leaves by vessels which act like pipes.
3.chlorophyll=green plants posses chlorophyll in their leaves which capture the energy of sunlight.
4.sunlight=sun is the natural source of sunlight, which provide solar energy to the plant, solar energy is converted into chemical energy by plants through photosynthesis. Thus sun is the ultimate source of energy.

Importance of photosynthesis

1.If the plants do not perform photosynthesis there would be no food on earth, photo synthesis is also necessary
2.for the production of oxygen gas in atmosphere which is necessary for respiration of organisms.therefore,it can be said that no life is possible in the absence of photosynthesis