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Biology - Introduction

Introduction

The protein, starch and lipids in our food are too large to be of much use
to us. They must be broken down into smaller substances before they can be
taken out of our digestive system to be used by cells. This is called
digestion. [1]

Food enters the mouth. This is called ingestion. [2]

While the food is in the digestive system it is physically broken down
into smaller pieces. This is called Special substances called act upon
the proteins, lipids and carbohydrates to break them down into simple
substances. This is

Monosaccharides [3] such as glucose, amino acids, glycerol and fatty acids
pass through the lining of the digestive system into either the blood
system [4] or the lymphatic system. [5]This process is called absorption.
[6]

Food that has not been chemically digested and absorbed passes out of the
body. This is called



Links:
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[1] http://alison.com/#
[2] http://alison.com/#
[3] http://alison.com/#
[4] http://alison.com/#
[5] http://alison.com/#
[6] http://alison.com/#