(1)Components of food which are necessary for our body are called nutrients.
Eg:- carbohydrates, vitamins, proteins, fats, minerals etc.
(2) The process in which food is taken by an organism and its utilisation by a body is called nutrition.
(3) The process in which organisms prepare food themselves from simple substances is called autotrophic nutrition.
(4) The organisms which can make their food themselves are called autotrophs.
(5) Autotrophs are derived from two Latin words auto means self and trophos means nourishment.
(6) Animals and most other organisms which can not make food themselves but take food prepared by plants are called heterotrophs.
Eg:- Animals, humans, birds etc.
(7) Heterotrophs are derived from two Latin words heteros means other and trophos means nourishment.
(8) Leaves are the food factories of plants because synthesis of food occurs there.
(9) Water and minerals present in the soil are absorbed by the roots and transported to the leaves by the vessels.
(10) Vessels are the pipes of plants which run throughout the root, the stem, the branches and the leaves.
(11)Stomatas are the pores on the surface of leaves which take carbon dioxide from air.
(12) The cells which are surrounded around the stomata are called guard cells.
(13)The green pigment present in the leaves is called chlorophyll. The leaves other than green colour also have chlorophyll, but large pigments mask the green colour.
(14) The process in which leaves use energy of sunlight to synthesis food from carbon dioxide and water is called photosynthesis.
(15)The photosynthesis is derived from two Latin Words photo means light and synthesis means to combine.
(16) During the photosynthesis oxygen is released by leaves. The carbohydrates get converted into starch.
(17)The presence of starch in leaves indicates the occurrence of photosynthesis.
Experiment—Take two same plants. Keep one of them in sunlight and other one in dark room. Check them after 72 hours. Take one leaf form each of them and pour few drops of Iodine solution on both leaves. The leaf which is taken from plant kept in sunlight turns blue-black but the leaf taken from plant kept in dark room turns red or shows no change in colour. It shows presence of starch indicates occurrence of photosynthesis.
(18)Algae are the organisms which is find in ponds and other water segments in the form of green patches. They can also prepare their food by photosynthesis which occurs due to presence of chlorophyll.
(19)Proteins are nitrogenous substances which contain nitrogen. Plants cannot take it directly from air. The Rhizobium bacteria present in the soil convert it into a soluble form and released it into the soil. The Rhizobium cannot make its own food .So it lives in the roots of gram, peas, moong beans and other legumes.
(20) Heterotrophic plants are those plants which can not prepare own food because of absence of chlorophyll .So, they use food prepare by other plants.
(21) The plant on which other plant climbs is called a host.
(22) The climber deprives the host of valuable nutrients, it is called a parasite.
(23) Insectivorous plants are those plants which eat insects.
Eg:- Pitcher plant.
(24)The mode of nutrition in which organisms take in nutrients in solution form from dead and decaying matter is called saprotrophic nutrition.
(25) Plants which take food from dead and decaying matter are called saprotrophs.
(26)Fungi also grow on pickles, leather, clothes and other articles that are left in hot and humid weather for long time.
(27) The relationship in which some organisms live together and share shelter and nutrients are called symbiotic relationship.
Eg:- Certain fungi live in the roots of trees. The tree provides nutrients to the fungus and, in return, receives help from it to take up water and nutrients from the soils.