Nutrition and Life Processes

1.0Introduction

If an organism is alive, it must keep repairing and maintaining its structures. The maintenance functions of living organisms must go on even when they are not doing anything particular. The processes which together perform this maintenance job are called life processes.

To maintain various life processes and to prevent damage and breakdown, energy is required. Energy is taken from the food.

The branch of biology that deals with the study of life processes or vital activities is called physiology.

The process which involves taking of food inside the body and utilizing it for various activities is called nutrition.

The digested food and inhaled oxygen are transported to every cell of the body through blood by the circulatory system. This process is called transportation.

Oxidation of food takes place inside every cell of the body by a process called respiration. In respiration, energy is generated and waste products are formed. These waste products are required to be removed from the body by a process called excretion.

• In unicellular organisms (like Amoeba), all the life processes take place through the entire surface of the cell because it is in direct contact with the environment.
• In multicellular organisms, all the cells may not be in direct contact with the surrounding environment, so they require specific organs for performing all the life processes.

2.0Criteria to Decide Whether Something is Alive

Living beings give response to stimuli and they show movement which may be visible (locomotion or movement of body parts) and invisible (at the molecular level). For example, the organization of cells into tissues, tissues into organs and organs into the organ system, all are dependent upon the movement of molecules. Therefore, molecular movement is basic to living beings.

Living beings can respire, grow, reproduce and they have the ability to evolve.

3.0Important Processes for Growth and Survival

There are Mainly Four Important Life Processes

Which are required for maintaining life, without which living beings cannot survive.

1. Nutrition (for obtaining nutrients)

2. Respiration (for releasing energy)

3. Transportation (for distribution of food and other materials)

4. Excretion (for removal of toxic wastes)

All these life processes take place only in living organisms.

All living organisms require energy and other raw materials for performing all the vital activities and for body building, repair, growth, development and regulation. Both energy and raw materials are obtained from the food. The food taken in by an organism contains a large number of nutrients like carbohydrates, fats, proteins, minerals, vitamins and water.

Carbohydrates and fats provide energy. Proteins are required for body building, growth and healing. Vitamins and minerals are the regulating nutrients.

4.0Define Nutrition

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

Nutrients are the organic or inorganic substances required for the maintenance of life and survival of living organisms.

Modes of Nutrition

Methods of obtaining food by the organisms are called modes of nutrition.

Autotrophic Nutrition

It is the process by which organisms take in simple inorganic substances from outside and use them to synthesize organic molecules and then convert it into stored forms of energy. For example, green plants prepare their food (glucose) by using carbon dioxide and water in the presence of chlorophyll and sunlight and store it in the form of starch. The organisms having autotrophic mode of nutrition are called autotrophs or autotrophic organisms.

Examples: Green plants and some bacteria.

5.0Photosynthesis

Photosynthesis is the process of preparing organic food (carbohydrate) by combining carbon dioxide and water, using solar energy with the help of chlorophyll pigments.

The sugar (glucose) produced in photosynthesis is stored in the form of starch in plants and it is the source of reserved internal energy.

Also refer : Site of Photosynthesis and Its Role in Plant Life

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