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| Nutrition and Its Types |
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| The term nutrition includes the way an organism obtains its food and also the processes by which the nutrients in the food are broken down to simpler molecules for the utilisation by the body. |
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| Thus, the study of the process of nutrition in various organisms gives us an idea about their nutritional requirements. This helps us in many ways like in taking care of domestic animals, poultry, farm animals, etc. so that we may get the best results from them. Since feeding is one of the basic requirements of any organism, the study of the food habits of different organisms leads to an understanding of the interrelationships between them and the balance that is maintained in nature. |
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| The mechanism by which organisms obtain food is referred to as the modes of nutrition. The organisms either synthesize their own food or obtain food prepared by other organisms in various ways. There are basically two modes of nutrition - autotrophic and heterotrophic. |
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| Autotrophic nutrition |
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| 'auto' means self and 'trophic' refers to food. So, the organisms, which synthesize their own food using CO2, are called the autotrophs and the process is called autotrophic nutrition. |
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| Autotrophs include all green plants and some bacteria such as the nitrifying bacteria. |
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| Heterotrophic nutrition |
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| 'hetero' refers to other or different and 'trophic' refers to food. Thus, the organisms that obtain their food from other organisms are called heterotrophs and the process of obtaining the food from other organisms is called heterotrophic nutrition. All heterotrophs depend directly or indirectly on the autotrophic organisms for their food and energy requirements. Heterotrophs include most of the bacteria, fungi and all animals. |
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| Note: |
| It is the carbon compounds that are the source of energy to all the organisms. In case of autotrophs, the source of carbon is inorganic. They use inorganic molecules to synthesize organic molecules. Whereas the heterotrophs derive energy from the organic substances synthesized by the plants. |
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| The organisms are classified into the two types based on their source of carbon. |
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