Page 21 - Science Class 07

again, but this me very slowly. You might have simpler food diffuses into the cytoplasm and
seen a cow chewing something all day long. undigested food is thrown out of the body.
This is nothing but the half digested food called Vacuolar diges ve system is found mostly in
cud that reaches its mouth from the re culum. unicellular organism, and is the simplest form
This process is called rumina on. This me the of diges on. Food is ingested and passed

half digested and proper chewed food directly through a cell in bubble like chambers called
enters the third chamber called the omasum. vacuoles. Enzyme organelles, or lysosomes,
Here, this food is further broken down. fuses with the vacuoles, the enzymes convert
Therea er, the food finally reaches the fourth the food into simpler compounds that can be
chamber called the abomasum. In this assimilated into cellular material. A er a
chamber, the food mixes up with various vacuole has crossed the cell, it is expelled out
enzymes and gets digested. along with the undigested food ma er.

NUTRITION IN AMOEBA
Amoeba is an unicellular organism which can
be seen only through a microscope. It has a
thin membrane present outside its body and it
is filled with protoplasm. It has a nucleus and a

few vacuoles. It can change its shape. When a
food par cle comes near it, it develops finger
like projects called pseudopodia. Gradually,
stretches two pseudopodia around the food Amoeba
(microscope plant or animal) and a vacuole is
created.

Amoeba engulfs that food in the vacuole.
Diges on of the prey takes place in the food A frog’s tongue is a ached to the front of its
mouth. It swallows its food whole. When a
vacuole in the cytoplasm. This type of diges on
frog eats something poisonous or bad
which takes place within the cell is called
tas ng, it can ‘throw up’ its en re stomach.
intracellular diges on. A er diges on the
The stomach actually comes out of the
frog’s mouth and emp es its contents.

Ingestion : The process of taking food inside the body
Digestion : The process in which food is dissolved chemically
Absorption : Process by which organisms absorb the nutrients broken down by simpler
substances

Assimilation : Distribution of absorbed nutrients to different body parts
Egestion : Elimination of undigested food materials
Peristalsis : A wavy movement in the inner wall of the food pipe

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