Nutrition An Important Life Processes

Nutrition An Important Life Processes

Nutrition is one of the important part  in life of living organisms. All living things perform various activities in their life and for performing this activities a living thing requires energy. The energy is obtained from food that a organisms eat.

Modes of Nutrition

Nutrition a important life process



  1. Nutrition – Nutrition can be defined as Intake of food by any living organism and  Utilization of that food is called Nutrition.
  2. Respiration – Respiration processes includes Breathing of oxygen as well as oxidation of food into cells to release energy.
  3.  Transportation – Transport of different gases as well as digested food to different parts of a body.
  4. Excretion – Excretion is removal of undigested, waste material from the body is called as Excretion.


Nutrition word is derived from the word nutrient. Nutrient can be an organic or inorganic form of food. This is used  for generation of energy to carry out various Physical and metabolic activities of living things. This process is important for survival of a living organism. Sources of food may be simple or complex. Glucose, Starch, Carbohydrate, Fats and Proteins, Vitamins are the different form of food used to derive energy.

In simple words Nutrient can be defined as the food consumed by living organism from the surrounding and utilize it as a source of energy . The energy obtained by the utilization of food is used for biosynthesis of the body components like cells, organs and tissues. The food taken by an organism is made up of nutrients like carbohydrates, fats , vitamins, minerals, protein and water. Thus we can define Nutrition as intake of food or we can say intake of nutrients and utilization of that nutrients by organism in form of energy.

1 ] Mode of Nutrition

Mode of nutrition in nothing but the method of obtaining of food by an organism. There are vast number of living things on earth and each and every species of life have a different method of obtaining or we can say intake of food. Depending on the method used for obtaining food the organism are divided into two main groups and that are

A] Autotrophic Mode of Nutrition

B] Heterotrophic Mode of Nutrition

A] Autotrophic Mode of Nutrition

Autotrophic mode of nutrition means nutrition carried out by own self. The organism synthesize its food by using the Carbon dioxide, Water and Sunlight as the source of energy.

Thus we can define it as” A mode of nutrition in which organism which synthesis its own food by used of carbon dioxide, water and sunlight as a source of energy” . The green plants show autotrophic mode of nutrition as they have chlorophyll pigment present in the cell. Some bacteria also show autotrophic mode of nutrition. The organisms which show autotrophic mode of nutrition are called as autotrophic organism or just autotrophs. This autotrophs make their food from inorganic substances present in the surrounding like carbon dioxide, water, soil and sunlight.

The chlorophyll pigment present in the cells of plants and this pigment is capable of trapping the sunlight energy.The processes of photosynthesis is used for making their own food by autotrophs. Photosynthesis is a processes in which the trapped carbon dioxide and inorganic substances like soil, water and carbon dioxide is used to prepare their own food.

B] Heterotrophic Mode of Nutrition

In heterotrophic mode of nutrition the nutrition is obtained from other sources.In this mode of nutrition the living things are unable to synthesize its own food they are depended on other life forms for their nutrition.In short we can say hetrotrophs are dependent on food that is made by autotrophs or consume autotrophs and other animals. Most of the organism are hetrotrophs like animals, bacteria, fungi and human beings.

We can define heterotrophs as ” The living things that are unable to synthesize their own food by using inorganic substances and are completely dependent on autotrophs and for their food and consume other animals are called as heterotrophs. Living things like bacteria, fungus, yeast, animals and human being are hetrotrophic in nature.

There are three types of Heterophic Nutrition

  1. Saprotrophic nutrition
  2. Parasitic nutrition
  3. Holozoic nutrition

1. Saprotrophic nutrition – Saprotrophic mode of nutrition is a nutrition where living things obtain its food from dead plants and animals. The meaning of ‘sapro’ means rotten so a saprophytic is a organism depend on dead and rotten plants and animal. The dead and decaying matter is in complex form this saprophytes convert this complex form of nutrients to simple form outside their body and then consume the simple form of nutrients. Generally the fungus like yeast, molds, mushroom and some bacteria are included in this class of saprophytes.

2. Parasitic nutrition – Parasitic mode of nutrition is a mode of nutrition in which the organism obtain its food from the body of other living organism. The parasite is a organism that enter the body of a host organism and derive its food without killing it. Parasite cause a harm to host.The diseases caused in plants, animals and human being  are due to parasites. Generally bacteria, fungi, and some plants show parasitic mode of nutrition

There are two types of parasites that are Ectoparasite and Endoparasite. Ectoparasite are the parasite that live on outer surface of host body that is skin surface of host. Endoparasite are the parasites that enter in the body of host and reach different organs of host.

3. Holozoic nutrition

Holozoic nutrition is a nutrition in which the living thing take a plant or animal product as food source. Generally most of the animals take the food in the body by processes of ingestion, further the complex food is taken and digested into simple molecules by process of digestion. The digested food is absorbed into to the cells of body by absorption. Lastly the undigested waste product are thrown out of body by process of egestion. Human beings and almost all animals show holozoic mode of nutrition.


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