lss module 3 chpt 10 nutrients an food

Module 3:Wonders of My Body (I)Chapter 10 Getting Energy And Nutrients From Food

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Chapter 10 Getting Energy And Nutrients From Food10.1 Why is food important for

living things? 10.2 How is food digested? 10.3 How does the body get

energy from food?


ObjectivesState the importance of digested

food substances as a source of energy and nutrients for building and repairing body tissues


Why do we need food?All living things need food.

Food provides energy for our body to do work.

Food is also needed for the growth and repair of damaged and worn-out tissues.

Food is important to us because it provides us with nutrients, water and dietary fibre.


A healthy diet

The food that we eat every day is called our diet. Our diet should contain carbohydrates, proteins,

fats, vitamins and minerals.


Dietary fibre and waterWe need water to:

(a) Dissolve and carry nutrients(b) Remove waste products(c) Maintain body temperature

Dietary fibre makes our solid waste soft,

bulky and easy to move through the digestive tract.

Fibre can also help us prevent constipation. We can obtain fibre from vegetables, fruits and cereals.


Getting Nutrients from our Food

Some of the food that we eat may be insoluble and made of large particles.

It must be digested before the body can make use of it. © Copyright Star Publishing

Pte Ltd

Why must food be digested?

When food is digested, it is broken down into simpler, soluble, smaller particles which enter the blood stream and are carried to all parts of the body.


Physical and Chemical digestion


How do enzymes help in digestion?

Large, insoluble food particles are broken down by chemical substances called enzymes into smaller, soluble particles which can enter the bloodstream and are carried to all parts of the body.




energy from food?


ObjectivesDescribe briefly how the different parts

of a digestive system help in the digestion of food

State that food is digested into smaller substances that are carried by the blood stream to the other parts of the body

Investigate the role played by enzymes in the digestion of food (names of enzymes are not required) and communicate findings


Parts of the Digestive SystemThe food that we eat enters the body

through the mouth and passes through the organs of the digestive system.

The digestive system is made up of the mouth, gullet, stomach, small and large intestines, the rectum and anus.

It also consists of the liver, pancreas and gall bladder.


The Digestive System


Activity Book LinkActivity 10.1The Human Digestive System

Digestion of FoodMouth

The size of the food we eat is too large for our body cells to absorb. When we chew, our teeth cut large pieces of food into smaller pieces.


Digestion of FoodMouth

Salivary glands produce and release saliva.

Saliva softens food and contains enzymes to digest starch into simpler forms.


Activity Book LinkActivity 10.2Enzyme Action onStarch Solution

Digestion of FoodTongue

The tongue rolls food into a ball and pushes it into the gullet.


Digestion of FoodGullet

Muscles of the gullet wall contract and relax to push the food down from the mouth into the stomach.

No enzymes are produced in the gullet.


Digestion of FoodStomach

The stomach is a muscular bag. It digests food by mashing food into a liquid mixture, producing enzymes to digest proteins.

The stomach also produces acid to kill bacteria in food.


Digestion of FoodSmall intestine

The small intestine is a long, coiled tube.

Digestion of all food is completed in the small intestine by different enzymes.


Digestion of FoodSmall intestine

Digested food is absorbed through the walls of the small intestine into the bloodstream.

Digested food will be carried by the blood to all parts of the body


Activity Book LinkActivity 10.3Digestion of Food

Digestion of FoodLarge intestine

No digestion happens in the large intestine.

Excess water and mineral salts are absorbed through the walls of the large intestine into the bloodstream.

Undigested food (faeces) moves into the rectum and is stored and leave the body through the anus.




energy from food?


ObjectivesState that when food is broken down

to release the energy trapped within it, oxygen is required, and carbon dioxide and water are produced

Relate breathing to the body’s need to get rid of carbon dioxide from the body

Investigate the presence of carbon dioxide in exhaled air using limewater


Why do we need energy?Our bodies need energy for the

following purposes:


Activity Book LinkActivity 10.4The Importance of Digested Food

The food we eat is digested so that it can combine with oxygen to give us energy.


How we get energy from food


RespirationIn the body cells, the digested food will

react with oxygen to release energy.

This process is called respiration.

During respiration, carbon dioxide and water are also produced.

They are removed when we breathe out.


Digestion, Breathing and Respiration


Activity Book LinkActivity 10.5Enzyme Action in the Digestive System

Why is breathing important?Breathing is the process by

which air is brought into the lungs and removed from it.

The air that we breathe in is called inhaled air.

The air that we breathe out is called exhaled air.


The composition of air we inhale and exhale is different


Why is breathing important?Breathing is important because

oxygen is needed to break down digested food to release energy for the body to do work.


Activity Book LinkActivity 10.6Characteristics of Inhaled and Exhaled AirActivity 10.7The Digestive and Respiratory Systems

lss module 3 chpt 10 nutrients an food

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