Class 7 Science

Animal Nutrition

Digestion

After taking of food, food is digested and then it is passed to the different parts of body for the growth, repair and other vital functioning of body.

The food we take is primarily in the form of complex substances. Food in such complex form is not used as such by animals. Hence, they need to be first broken down into simpler soluble forms so that they can be absorbed by the cells of the body.


The process of breaking down of complex component of food into simpler substances is called digestion. The process of digestion is different in human, grass eating animals, amoeba, hydra, etc.

Enzymes help in the breakdown of complex molecules like carbohydrates, protein, fats, etc. into simple molecules.

Digestion in unicellular animals; like Amoeba; is intracellular. The digestive enzymes are secreted in the food vacuoles.



Question 1: What is ingestion?

Answer: The intake of food is called ingestion.

Questions 2: What is digestion?

Answer: The breaking down of solid and complex food into simple and soluble forms is called digestion.

Question 3: What is absorption?

Answer: The process of passing of digested food into blood vessels in the intestine is called the absorption.

Question 4: What do you understand by assimilation?

Answer: The conversion of absorbed food in complex substances such as proteins and vitamins required by body is called assimilation.



Question 5: What do you understand by egestion?

Answer: Removal of waste materials from the body, time to time from anus is called egestion.

Questions 6: What are the steps of nutrition involved in animals?

Answer: There is five steps of nutrition involved in animals. These are Ingestion, Digestion, Absorption, Assimilation and Egestion.

Questions 7: What are Pseudopodia?

Answer: Finger-like outgrowths on amoeba are called pseudopodia.

(The word pseudopodia is the combination of pseudo and podus. Pseudo means false and podus means feet. Singular of pseudoposida is pseudopodium)