Food and Nutrition


Food is the basic requirement for survival of all living organisms. animals depend directly or indirectly on green plants to obtain food. The process of taking food and getting energy for it form growth and development is called nutrition. Energy is released when food substances present in living cells breakdown chemically through a process of oxidation.


The Living World
Nature and Scope of Biology
Physical Activity for good health
Balance Diet and Nutrition

Autotrophic Nutrition

The mode of nutrition in which organisms make food themselves from simple substance is called autotrophic nutrition. All green plants and some bacteria have an autotrophic mode of nutrition. Green plants prepare their food by the process of photosynthesis. Leaves are the food factories of plant and help in synthesis of food. Roots absorb water and minerals present in soil which are transported to leaves.

  • Carbon dioxide: stomata present on leaves take in carbon dioxide from the atmosphere. These sports are surrounded by guard cells which regulate their opening clothes and closing.
  • Chlorophyll: green pigment present in leaves is called chlorophyll. It helps to capture the energy of sunlight which is used to prepare food from carbon dioxide and water.
  • Sunlight: energy from the sun is captured by leaves and stored in plant in the form of food.
  • Water: water along with minerals present in the soil is absorbed by roots of a plant and transported into leaves through xylem.

Heterotrophic Nutrition

mode of nutrition in which organ depends upon other plants and animals to obtain their nutrition is called heterotrophic nutrition. Such organisms are called heterotrophs. They are unable to synthesise organic compound to be used as food. All heterotrophs depend on autotrophs for their nutrition. Some plants, animals and bacteria, which do not have chlorophyll, fat under this category.

Parasite plant

parasite leaves in or another living organism and derives its food from them. The living organism from which parasite derives its food is called the host. usually parasitic plant develop special root which penetrate into the tissue of host plant. The prepared food is generally observed from the roots are the stem of the host plant. The parasite its host of valuable nutrients.

Cuscuta our dodder does not have chlorophyll. It leaves are reduced to tiny brown scales. It’s time twins around the host producing suckers called historias that invade the host and steal its food. It takes readymade food from the plant on which it is climbing.
Mistrato is another parasitic that steals water and minerals from the host tree. However, it has green leaves and produces its own food through photosynthesis, using water absorbed from the host tree is called a partial parasite.

Saprophytic plant

Saprophytic plants feed on dedicating material to obtain nutrition. Indian pipe fungi and bacteria are saprophytes. they secrete digestive juice to convert the solid dead and decaying matter into liquid and derive their nutrition from it.
Hot and humid weather favours the growth of fungi which can be seen during rains. You must have seen mushrooms in the market and might have eaten them too. This is an edible fungus. But remember, all mushrooms are not edible.

Insectivorous plant

the plant such as venus flytrap and picture plant which feed upon small insects are called insectivorous plants. They have a special structure to catch their prey. These plants are usually green in colour and prepare their own food. They eat insects because they grow in soil that is deficient in nitrogen. They fulfil their nitrogen requirements by eating insects.
in sundew plant, the leaves have tentacles with droplets of sticky substance at the end. Insects that sit on the leaves get stuck to the substance and is consumed by the plant.

The apex leave for the male lead which can open and close the mouth of the picture inside of the picture is blind with downward-pointing hairs, which do not allow the trap insects to escape. When an insect is trapped in the picture it is digested by the digestive juice present in it.


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