WHAT IS NUTRITION ?
Here are some easy definitions of Nutrition.
Nutrition is the process of taking or consuming food. It is the process by which food is consumed and used to provide energy and nutrients.
Nutrition depends on taking, administration or ingestion of food; which is then utilized for energy and nutrients.
Nutrition can be defined as taking or consumption of foods and or nutrients. It implies the use of the resource to support energy requirements as well as nutrients that may be required in the body.
Nutrition entails the process of feeding or consuming food so as to gain energy and nutrients.
Food intake or feeding is the procedure or technique of nourishment which is employed in the provision of energy and food factors.
The basic modes / models of Nutrition are Autotropic Nutrition and Heterotrophic Nutrition.
Autotrophic Nutrition : Auto-trophic nutrition where a living thing manufactures it’s food from simple substances such as water, carbon and mineral salts in presence of sunlight. Green plants comprise of the following have an autotrophic mode of nutrition.
Heterotrophic nutrition: Heterotrophic mode of nutrition is a nutrition in which the organisms is not able to manufacture their own food and therefore have to feed on other organisms. The heterotroph word is formed from the prefix “hetero” which means “other” and the root word “ trophe” meaning “nutriture”.
Heterotrophs cannot synthesize food on their own from raw materials such as carbon dioxide and water, and have no chlorophyll or green colour. Instead, they absorb such less complex structures as organic compounds that, as a rule, are derived from plants or animals in order to exist.
Easy Definition of Autotrophic and Heterotrophic Nutrition.
- Autotrophic Nutrition: the term autotrophic is derived from two Greek words auto means self and drop means nutrition. In autotrophic nutrition an organism manufacturers its own food from simple inorganic raw materials ( carbon dioxide and water) in the presence of sunlight. All green plants, some bacteria and some protozoan have autotrophic . This more of Nutrition is a treat mainly by the process of photosynthesis. During this process the green plants use raw materials I can’t dioxide, water and minerals salt and sunlight to send the size organic compound in the form of sugar.
There are also some organisms like green sulphur bacteria which drive hydrogen from hydrogen sulphide instead of water. The protozoan namely Euglena is normally autotrophic but some species can survive heterotrophically in darkness if an organic carbon source is present. - Heterotrophic Nutrition: the term heterotrophic is derived from two Greek words hetero means other and troph means nutrition. This heterotrophs are organisms that feed on a complex readymade organic food. They use it as a source of (I) energy for their vital activities (ii) building materials for growth and repair. (iii) Vitamins that cannot be synthesized in the organisms.
Heterotrophs’ sustenance is either direct or indirect, therefore the synthetic activity of autotrophs is all important. Most animals, fungi and bacteria are heterotrophic; a minority of bacteria and algae are autotrophic. The main form heterotrophic Nutrition are classified as holozoic, saprotrophic and Paristic.
A) Holozoic Nutrition: the world holozoic is derived from the Greek word holo means whole and zone means animals. All organisms feeding in this way take food into the body where it is then digested into smaller soluble molecules which can be absorbed . The term hollozoic is applied to mainly free living animals which have a specialised digestive tract in which these processes occur .The characteristic process involved in holozoic nutrition are;
a) Ingestion: It is the taking in of complex organic food.
b) Digestion: It is The breakdown of large complex in soluble organic molecules into small simple and soluble molecules.
C) Absorption: It it is the uptake of soluble molecules from the digestive region ، across a membrane into body tissues .
D) Assimilation: It is the use of absorbed molecules by the body to provide either energy or materials to be incorporated into the body.
E) Egestion: It is the elimination of undigested waste food materials from the body.
B) saprotrophic nutrition: organisms which feed on dead or decaying organic matter are called saprotrophs. Many fungi and bacteria are saprotrophs. These organisms secrete starch digesting enzyme on to potential food with it is digested. The soluble and production of this extra cellular chemical decomposition are then absorbed and assimilated by ,saprotrophs.
C) parasitic nutrition: parasitism is close association between two living organisms of different species which is beneficial to one i.e the parasite and harmful to other i.e host. The parasite obtains food from the host and generally shelter. A successful parasite is able to live with the host without causing it any harm.The parasite which live on the outer surface of the host are called ecto parasite, e.g lice , ticks etc and the parasites which live within the host are called endo parasites, e.g round worm, ring worm , tape worm , plasmodium etc .
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