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PinkMonkey Online Study Guide-Biology

CHAPTER 16 : NUTRITION AND DIGESTION

16.0 Introduction

Every organism needs a continuous supply of metabolites for growth and energy to function normally in life. Most organisms get both metabolites and energy from the food they consume.

Food is the first requisition of the process of nutrition. It is essential for several purposes :

  1. It provides metabolites or building material for the body of an organism.

  2. It constitutes a source of energy for the organism.

  3. It also helps in the normal functioning and well balanced growth of the body.

  4. It compensates for the wear and tear of the body.

The process in which food is obtained, prepared, absorbed and converted into body substances, is called nutrition. It is the main life-sustaining process in an organism: it provides the raw materials for the maintenance of life.


Nutrition in animals occurs in five phases namely (i) feeding or ingestion, (ii) digestion

(iii) absorption and (iv) assimilation.

  1. Ingestion is the process of taking in food.

  2. Digestion is the process of breaking up complex substances into simpler substances.

  3. Absorption is concerned with diffusion of digested food into blood and lymph.

  4. Assimilation is the conversion or incorporation of absorbed simple food into the complex substances constituting the body.

  5. Egestion is the elimination of undigested food from the body.

Figure 16.1 Nutrition in higher animals

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Table of Contents

16.0 - Introduction
16.1 - Nutritional Requirements, Imbalances and Deficiency Diseases
16.2 - Organs of Digestion and Physiology of Digestion

Chapter 17





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