HUMAN NUTRITION (SCIENCE FORM 2)

Human
Nutrition

What is nutrition &
Why does it matter

EKDSISTMION

Science Form 2

NURIN WAJIHAH BINTI MOHD ZAMANI

HUMAN NUTRITION
SCIENCE FORM 2 (CHAPTER 3)

EFFECTIVE REFFERENCE BOOK WITH GRAPHICS AND DIAGRAMS

Author : NURIN WAJIHAH BINTI MOHD ZAMANI

Pelangi Publications Sdn.Bhd
Lot 8,Jalan P10/10,Kawasan Perusahaan Bangi,
Bandar Baru Bangi,43650 Bangi, Selangor Darul
Ehsan,Malaysia.
Tel:03-89223993
Faks: 03-89261223
E-mel: [email protected]

Associated companies, branches and representatives
throughout the world

Pelangi publication Sdn.Bhd 2022

All right reserved. No part of this publication may be
reproduced, stored in a retrieval system or transmitted in
any form by any means electronic, mechanical,
photocopying, recording or otherwise without the prior
permission of the copyright owner.

i

ACKNOWLEDGEMENT

First and foremost, I would like to praise and thank
the Almighty God for giving me strength and because of
his blessing, I managed to accomplish this lesson book.

I would like to address a big thanks to everyone
that help to contribute ideas and give advice in helping
me to complete this lesson book.

On the other hand, I would like to express deep and
sincere gratitude to my lecturer Madam Siti Fairuz
Dalim because without her guidance this lesson book
cannot been done properly like this. She always gives
me guidance and support in purpose to produce good
outcomes for my lesson book entitle Human Nutrition
which is chapter 3 in the science form 2 textbook.

Finally, I was also overwhelmed by the support
given by my classmates. A big thanks to you guys for
always giving positive comments to me to complete this
lesson book.

I hope that my lesson book will give a lot of benefits
to science students out there.

ii

PREFACE

This lesson book was created based on the Science textbook KSSM form 2 and
the Dokumen Standard Kurikulum Pentaksiran (DSKP) provided by the Ministry of
Education, Malaysia. This book aims to help students understand and master chapter
3: Nutrition in theme 1: Maintenance and continuity of life. It is guided by the
concepts of Scientific skills, Science Process Skills, Higher Order Thinking Skills, 21st
Century Skills and the STEM teaching and learning approach. Malaysia is one of the
highest obesity cases in the world. The major cause of this obesity to happen because
of food intake. So it is important to understand about nutrition to ensure a healthy
balanced diet.

Special features

Learning outcome Summative exercise


Question to test students
Statement of what understanding at the end of
students expected to get
and learn in this book each subtopic

Brain teaser Mindblown corner

A brain teaser is a form of Additional information
puzzle that requires thought added to the subtopics’

to solve theories and concept

iii

Table of content

Copyright page i
Acknowledgement ii
Preface iii

Nutrition 1-5
6-9
3.1 Class of Food 10-13
14-16
3.2 Importance of a Balance Diet 17
18
i

3.3 Human Digestive System

3.4 Process of Absorption &
Transportation of Digested
Food and Defecation

Summative Practice

References

3.1 Class of Food

What is your daily
diet?

Is it nutritious and
energy-giving?



1

3.1 Class of Food Learning outcome

Food not only supplies energy but At the end of the lesson, student
will be able to elaborate and
also gives nutrients to maintain our health. communicate correctly about
seven classes food.

Nasi lemak Satay Can you identify the food
classes that are shown in
Photograph 3.1 Food is a basic need for humans
each food item in
Food is divided into seven main classes : Photograph 3.1?

carbohydrate

protein

fat Each food class has
vitamin a specific function
mineral

fibre

water

.

Class of Food

carbohydrate protein fat vitamin mineral fibre water

Figure 3.1 Class of Food 2

Carbohydrate Examples of carbohydrate

Carbohydrate is an organic compound that contains Starch
Carbon
Hydrogen Starch is the food
Oxygen. stored in plants

Carbohydrate is a staple for humans because it Glycogen
supplies a lot of energy
Glycogen is the food
Banana Rice Honey stored in animals

Cellulose

Cellulose is the
carbohydrate that forms
the cell walls of plants

Bread Potato Sugar Mindblown corner

Some sou
rces of
carbohydrate, such as sugar

supply energy quickly

Photograph 3.2 Sources of carbohydrate

Protein Proteins we eat are digested to the basic unit, that is
amino acid.
Protein is an organic compound that contains
Carbon, Funtion protein
Hydrogen
Oxygen
Nitrogen

For growing to repair damaged tissues to synthesise
in the body as well as to enzymes, hormones

replace dead cell and antibodie

Mindblown corner

Kwashiorkor is a kind of
disease caused
by protein
deficiency in human diet and
it generally occurs in children
aged between 1 and 3 years.

Photograph 3.3 Sources of protein 3

Fat Fat is formed from glycerol
and fatty acid.
As in carbohydrates, fat contains: Fat is a high energy source
Carbon and storage.
Hydrogen Each gramme of fat
Oxygen. supplies two times the
total energy supplied by
Funtion of fat carbohydrates.

Fat protects the organs of the body Mindblown corner
such as the heart and kidneys.
Fat acts as a transporter for Fat from anim
als contains
vitamin A, D, E and K. higher cholesterol than fat
Excess fat in the body is stored
under the skin as a heat insulator from plants
to regulate body temperature.

Butter Coconut Oil Palm Oil Groundnuts

Photograph 3.4 Sources of fat

Vitamin

Vitamin is an organic compound that Meat Milk Fruit Vegetable
does not supply energy, but is needed by
the body in small quantities to maintain Photograph 3.5 Sources of vitamins
good health

Vitamin

water-soluble fat-soluble
vitamins vitamins

Vitamin Vitamin A,
B and C D, E and K

Figure 3.2 Classification of vitamins Table 3.1 Type, source, importance and effects of vitamin deficiency 4

Fiber Fruits, vegetables
and grains are
Fibre is a substance that cannot be broken high in fibre.
down by the digestive system.
Fibre comprises of cellulose that is found Summative exercise
in the cell wall of plants.


Fibre is very important to stimulate peristalsis, Vegetables Grains
that is, the movement caused by the constriction
and relaxation of the muscles along the High Fibre Bread
digestive tract such as esophagus, small
intestine and large intestine. Photograph 3.6 Sources of fibre
This makes it easier for food to move along the
digestive tract and prevents constipation.

Mineral

Mineral is a non-organic substance
required by the body.
Minerals do not supply energy, but are
required in small quantities to regulate
body processes to maintain health.

Salt Seafood Table 3.2 Types, sources, importance and effects of mineral deficiency

Photograph 3.7 Sources of mineral

Water We need to drink at
least 2 litres of water
Water is a compound that is very important to
our body. a day
Water contains elements of hydrogen and
oxygen. Water acts as a chemical solvent and a
transportation medium of nutrients and oxygen into
Fruit juice Watermelon the cells. 5
It transports waste materials such as urea and salt
out of the cells and regulates body temperature
through evaporation of sweat.

Photograph 3.8 Sources of water

Importance of

3.2 Balanced Diet

What is meant by a
balanced diet?

6

3.2 Importance of Balanced Diet

A balanced diet is a diet that contains
all the food classes in the right
quantities that are required by the
body.

Learning outcome

Wfogeoucdiadhnpeeryaterolfatehpmryritedmopaatehsraeela.a Mother, how do I

prepare a healthy By the end of the lesson, students
will be able to explain correctly six
meal? factors that influence calorific
requirements .

Mindblown corner

The “Healthy Plate” model has

been prepared b
y the Ministry

of Health Malaysia as a guide
to practise a balanced diet.

Heathy Plate’ Model
http://www.moh.
gov.my/index.php/

pages/view/84

Source: Ministry of Health Malaysia 7

Factors that Influence Calorific Requirement

Body size

A person with a large body frame needs to take a
bigger portion of food because he or she needs to
have more energy compared to someone with a
smaller frame

Age

Children and teenagers require more carbohydrates
for energy and protein for growth because they are
growing and are more active compared to adults.

Work

Farmers, labourers and fishermen require more
energy because they do heavy work. Therefore, their
diet requirements are higher compared to people
who work in an office.

Gender

Generally, men are more muscular and they do
more heavy activities. Therefore, they need bigger
food portions than women

State of health

People who are sick are weak. They
require food suitable to their health
condition.

Climate

People who live in cold climate countries lose heat quickly
to their surroundings compared to people who live in hot
climate countries. Therefore, they need more food to
maintain their body temperature

Figure 3.8 Factors that influence a calorific requirement 8

Calorific Value of Food

Food contains some basic classes such as :

Carbohydrate All of these basic classes
protein produce different quantities of
Fat energy when burned.

Energy value / The total amount of energy
Calorific value released when 1 g of food is
burned completely in the body

This total energy is measured in units of calorie (cal) or joule (J).

1 calorie (cal) = 4.2 joule (J)
1 kilocalorie (kcal) = 4.2 kilojoule (kJ)

Table 3.3 Energy value of fat, protein and carbohydrate Summative exercise



The Importance of Maintaining Health

According to the research results of the National We need to practise a healthy
Health and Morbidity Survey (2016), the percentage lifestyle such as eating food
of Malaysians with diabetes is 17.5%, high blood with less sugar, salt, oil and fat.
pressure is 30%, high cholesterol is 47%, obesity Besides, we need to exercise to
is 17% and overweight is 40%. This problem shows avoid from serious diseases.
the improper diet and lifestyle of Malaysians.
Mindblown corner
9
The research results of the National
Health and Morb
idity Survey 2016

shows that only
six percent of

Malaysian adults eat enough fruits
and vegetables. Thus, the Ministry of
Health Malaysia launched the Eat
Fruits and Vegetables Campaign.

Human Digestive

3.3 System

Wbhoadtyhaafptperenwseineaot?ur

How the food is digested?

10

3.3 Human Digestive System

Food digestion is process of breaking down food that is Learning outcome
complex and large into molecules that are small,simple and
soluble so that they can be absorbed by the cells of the body


Digestion By the end of the lesson

,student will be able to label

correctly the eleven structure

of human digestive system .

Physical Chemical Mindblown corner


The process of breaking down

The process of breaking down food into smaller particles in
food into smaller particles in mouth with the help of Enzyme is a
substance
mouth with the help of teeth, enzyme. in the body that speeds
tongue and saliva. up chemical digestion.
Involved peristalsis

Happens in Break down Happens in
the mouth of food occur the mouth,
stomach,
Physical Chemical duodenum and
digestion digestion intestine

Does not Happen in Involves
involve the digestive enzymes
enzymes
tract

Figure 3.10 Comparison between physical digestion and chemical digestion

The Structure of the Human
Digestive System

What are the organs Brain teaser
that are involved in the
If a digestive tract is 9 m
human digestive long, how does the tract fit
system? into a body that is 1.5 m in

height?

The human digestive system comprises a tube that is
called the digestive tract and a few other organs such as
the liver, gall bladder and pancreas. The digestive tract is
a long tube that begins in the mouth and ends at the
anus .

11Figure 3.11 Human digestive system

The Flow of Food in the Mouth
Digestive Tract Oesophagus

What happens when Stomach
food passes through Duodenum
each organ in the
digestive tract ? Small intestine
Large intestine
Mouth
• Food is chewed by the teeth. Rectum
• Particles of food are softened by saliva. Anus
• Salivary amylase in saliva breaks down
starch into maltose. Figure 3.12 The
flow of food
Oesophagus particles
• Food that enters the oesophagus is called
bolus. 12
• The process of peristalsis at the wall of
the oesophagus pushes the food into the
stomach.

Stomach
• Walls of the stomach secrete protease and
hydrochloric acid. Hydrochloric acid
activates the protease and kills bacteria in
the food that enters the stomach.
• Protease breaks down protein into
polypeptides.
• Food that is semi-liquid is called chyme.

Duodenum
• Food enters the first part of the small intestine, that is, the
duodenum.
• The liver produces bile that is stored in the gall bladder.
• The bile emulsifies fat into small droplets and neutralises the acid in
the chyme.
• The pancreas produces pancreatic juice which contain enzymes
amylase, protease and lipase.
• Pancreatic amylase digests starch into maltose.
• Protease digests polypeptides into dipeptides.
• Lipase digests fat into fatty acids and glycerol.

Small intestine
• The small intestine secretes enzymes maltase and
protease.
• Maltase digests maltose into glucose.
• Protease digests dipeptides into amino acids.

Large intestine
• Undigested food will enter the large intestine.
• The process of water reabsorption happens in the large
intestine

Rectum
• Food that is undigested, known as faeces,
enters the rectum and is stored here.

Anus
• Faeces are excreted from the

body through the anus.

Mindblown corner
Some deterge
nts contain
enzymes. The
se enzymes
help to remove stains such

as blood and oil.

Summative exercise

Figure 3.13 Human digestive Figure 3.14 Action of digestive enzymes
system
13

3.4 Process of Absorption and
Transportation of Digested
Food and Defecation

How the food
absorbed in our

body?

14

3.4 Process of Absorption and Transportation of Digested

Food and Defecation

Observe the thread
Learning outcome

projections on the

surface of the towel.

What can you see? Following this sess
ion, students will

be able to relate correctly the function

of digestive system, blood circulatory

system and respiratory system .

Like the towel, the wall of Digested food which is made up of Mindblown corner
our small intestine has tiny molecules is easily absorbed into
millions of fine projections the blood circulatory system through Villus - s
ingular
called villi. This increases the the walls of the small intestine. Villi - plural
surface area for the process of These tiny molecules are then taken to
every part of the body Brain teaser

absorption of digested food. Why does our small
intestine
The surface of the small intestine has many folds to
add to the surface area and increase the absorption have more blood vessels
than our stomach?
rate of the products of digestion.

The wall of the villus is very thin. Mindblown corner
It is one-cell thick to increase the

Lacteal absorbs digested fat in
rate of absorption
the villi of the s
mall intestine.
The function of the blood vessels in the small
intestine is to transport nutrients to all parts of the The lacteal transfers it into the
lymphatic system and then to
body. the blood circulatory system.

(a) Villi on the walls of the small intestine

(b) Absorption and transportation of the products of digestion

Figure 3.16 Structure of villus and absorption of digested food in the small intestine 15

Process of Transporting the Products of Digestion

Food that is digested and Assimilation is a process of distributing
absorbed into a villus the end products of digestion for the use
needs to reach the cells of
the body. of the cells in our body
The molecules that are
absorbed into the villus Our body uses the end products of digestion as follows:
will undergo assimilation
• Glucose is used to produce energy.
• Amino acid is used to form component of cells.
• Fatty acid and glycerol combine to form fat which is used
as heat insulator and to protect internal organs

All these three systems below work together to ensure the Learning outcome
digested food molecules reach the cells of the body. At the en
d of the
lesson,stud
ents will be
Digestive system Breaks down large and complex particles of food able to elaborate and
into small and simple molecules so that they can be communicate correctly
about defecation.
absorbed into the villi

Blood circulatory Transports small and simple molecules to the cells of
system the body

Assimilation End products are distributed for: Summative exercise
formation of new cells

respiration
regulation of body temperature

Defecation Undigested food and food that is not absorbed by the
small intestine such as fibres, waste secretions of the
What happens to digestive tract, dead cells and water will move into the
the food that is not absorbed large intestine.
by the small intestine? While moving through the large intestine, water and
minerals are reabsorbed into the blood stream.
This makes the unabsorbed and undigested food to 16
become solid waste called faeces
Faeces are stored temporarily in the rectum before being
eliminated through the anus.
The process of elimination of faeces from the body is
called defecation.

Summative Practice

1. Figure 1 shows a food pyramid

Get the answer here

Figure 1

i) Stated 3 class of food in the figure 1
ii) State the functions of that class .

2. Jack lives in the Arctic which has a temperature as low as -42°C.

a) What class of food should Jack consume continuously to adapt herself to the cold
temperature?
(b) Give reasons for your answer in 2 (a)

3. State three factors that influence calorific requirement.

4. Figure 2 shows the human digestive system.Identify parts P to U.

P

S

QR

UT

Figure 2

5. What is the function of the blood vessels in the small intestine ?

17

References

Chowdhary, D. S. (2018, September 14). Kwashiorkor: Protein malnutrition - causes,
symptoms, diagnosis, treatment, complications and prevention. Medindia. Retrieved
July 12, 2022, from https://www.medindia.net/patientinfo/kwashiorkor-
malnutrition.htm?utm_source=canva&utm_medium=iframely

Gudipati, M. (n.d.). Human digestive system | download scientific diagram.
Retrieved July 11, 2022, from https://www.researchgate.net/figure/Human-
digestive-system_fig4_265948297

Muiz, M. (2016, March 15). Malaysian Food Pyramid. PORTAL MyHEALTH.
Retrieved July 12, 2022, from http://www.myhealth.gov.my/en/malaysian-food-
pyramid-2/

Textbook science form 2. anyflip. (n.d.). Retrieved July 12, 2022, from
http://online.anyflip.com/rzgru/kvda/mobile/index.html
hudayusof123. (2020, January 2). DSKP KSSM Science Form 2 - Hudayusof123
Flip PDF. AnyFlip. Retrieved July 12, 2022, from
https://anyflip.com/iyauw/ulsf

18

“ The doctor or the future will no longer treat the
human frame with drugs ,but rather will cure and

prevent disease with nutrition.”

-Thomas Edison

Pelangi Publication Sdn.Bhd W.M : RM 11.65
Lot 8,Jalan P10/10,Kawasan Perusahaan Bangi, E.M :RM 11.95
Bandar Baru Bangi,43650 Bangi, Selangor Darul
Ehsan,Malaysia.
Tel:03-89223993

Faks: 03-89261223
E-mel: [email protected]