Notes

Nutrition:

The process in which food is obtained or prepared, absorbed and converted into body substances for, for growth and energy is called nutrition.

Nutrients:

Nutrients are the elements and compounds that an organism obtains and use as energy source or as components for the synthesis of new materials.

Nutrition is essential for several purposes:

1. It constitutes a source of energy for the organism.
2. It provides building material for growth and development.
3. It regulates various body functions.

We know that autotrophic organisms (some bacteria, all algae, and all plants) obtain water, carbon dioxide, and minerals from their environment and prepare their food which is then used for growth and energy. On the other hand, heterotrophic organisms (most bacteria, and all protozoans, fungi, and animals) obtain their food from other organisms and use it for growth and energy.

Macronutrients:

The elements which are required by plants in larger quantities are called macronutrients. These are nine in number.

Micronutrients:

The minerals elements which are required in lower quantities are called micronutrients. These are eight in number.

Note:

If any one of these is not supplied, plants display abnormalities of growth and do not reproduce normally.

Note: Carbon and oxygen are absorbed from the air, while other elements are absorbed from the soil.