Life Process Notes for Class 10 Biology : Nutrition

These are the CBSE class 10 biology notes on chapter Life Process Topics covered in this page are
  1. Introduction
  2. Types of Life Processes
  3. Nutrition
  4. Mode of Nutrition
  5. Autotrophic Nutrition
  6. Heterotrophic Nutrition
  7. Types of Heterotrophic NUtrition


  • All the plants and animals are alive or living things.
  • The most important criterion to decide whether something is alive or not is the movement.
  • The movements in animals are fast and can be observed easily but the movements in plants are slow and observed with difficulty.
  • Animals can move from one place to another or they can move their body parts.
  • The plants can only move parts of their body such as leaves, flowers, roots and shoots.

Life Processes

The basic functions performed by living organisms to maintain their life on this earth are called life processes.
Basic life processes common to all living organisms are:
Basic life processes
Taking of food inside the body and converting it into smaller molecules which can be absorbed by the body.
The process which releases energy from the food absorbed by the body.
The process in which a substance absorbed or made in one part of the body is moved to other parts of the body.
The process in which the waste materials produced in the cells of the body are removed from the body.
Control and coordination
A process which helps the living organisms to survive in the changing environment around them.
The process involves the changes from a smaller organism to a big organism.
The organism either moves from one place to another or moves its body parts.
The process involves the making of more organisms form the existing once.
  • All the living organisms need energy to perform various life processes. They get this energy from food. Food is a kind of fuel which provides energy to all the living organisms.


  • Food is an organic substance. The simplest food is glucose also called simple sugar.
  • A more complex food is starch. It is made from glucose.
  • The general name of substances like glucose and starch is ‘carbohydrates’.
Nutrient: A nutrient can be defined as a substance which an organism obtains from its surroundings and uses it as a source of energy or for the biosynthesis of its body constituents.
Example: carbohydrates and fats are the nutrients which are used by the organism mainly as a source of energy.
Proteins and mineral salts are nutrients used by organism for the biosynthesis of its body constituents like skin, blood, etc.


Nutrition is the process of intake of nutrients (like carbohydrates, fats, proteins, minerals, vitamins and water) by an organism as well as the utilization of these nutrients by the organism.

Mode of Nutrition:

Mode of nutrition means method of obtaining food by an organism. There are mainly two modes of nutrition:
  1. Autotrophic mode of nutrition
  2. Heterotrophic mode of nutrition
Autotrophic mode of nutrition: (‘auto’ means ‘self’ and ‘trophe’ means ‘nutrition’)
  • Autotrophic nutrition is that mode of nutrition in which an organism makes (or synthesizes) its own food from the simple inorganic materials like carbon dioxide and water present in the surroundings (with the help of sunlight energy).
  • Those organisms which can make their own food from carbon dioxide and water are called autotrophs.
  • Example: all green plants, autotrophic bacteria.
  • Autotrophs make their food by photosynthesis.

Heterotrophic mode of nutrition: (‘heteros’ means ‘others’ and ‘trophe’ means ‘nutrition’)

  • Heterotrophic nutrition is that mode of nutrition in which an organism cannot make (or synthesizes) its own food from simple inorganic materials like carbon dioxide and water, and depends on other organisms for its food.
  • Those organisms which cannot make their own food from inorganic substances like carbon dioxide and water, and depends on other organisms for their food are called heterotrophs.
  • Example: all the animals (man, dog, cat, lion, etc.), most bacteria and fungi.

Types of Heterotrophic Nutrition:

 Heterotrophic mode of nutrition is of three types:
  1. Saprotrophic (saprophytic) nutrition
  2. Parasitic nutrition
  3. Holozoic nutrition

Saprotrophic nutrition:

  • Saprotrophic nutrition is that nutrition in which an organism obtains its food from decaying organic matter of dead plants, dead animals and rotten bread, etc.
  • The organisms having saprotrophic mode of nutrition are called saprophytes.
  • Saprophytes are the organisms which obtain food from dead plants (like rotten leaves), dead and decaying animal bodies, and other decaying organic matter.
  • Example: Fungi (liker bread moulds, mushrooms), and many bacteria.

Parasitic nutrition:

  • The parasitic nutrition is that nutrition in which an organism derives its food from the body of another living organisms without killing it.
  • A parasite is an organism (plant or animal) which feed on another living organism called its host.
  • Example: some animals like Plasmodium and roundworms, a few plants like Cuscuta (amarbel) and several fungi and bacteria.

Holozoic nutrition:

  • The holozoic nutrition is that nutrition in which an organism takes the complex organic food materials into its body by the process of ingestion, the ingested food is digested and then absorbed into the body cells of the organism.
  • Example: human beings and most of the animal.

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