SMSA YEAR 8 SCIENCE NOTES AND QUESTION BOOKLET

TOPIC 9: ABUSES OF LIFE PROCESSES

9.1 DRUGS
A drug is any substance which, when taken into the body, has an effect on the way the body and brain work.
Drugs may be divided into two main groups:

a) Useful drugs or medicinal drugs, e.g. paracetamol, antibiotics.
b) Harmful drugs, e.g. alcohol, heroin.

USEFUL DRUGS

1. Antibiotics are useful drugs that are used to fight diseases caused by harmful bacteria.
 Example, bacteria which cause tuberculosis (TB), pneumonia, dysentery and cholera.

 One example of antibiotic is penicillin.

 They have no effects against diseases caused by viruses.

 One common antibiotic is penicillin.

It is important a person finishes his prescription of antibiotic even if he feels better.

If the bacteria are not completely killed, the person may fall sick again and the bacteria may become
resistant to the antibiotic – the antibiotic is no longer effective against the bacteria.

Page1

2. Antacids are drugs used to cure indigestion.

An antacid neutralizes the excess acid in the stomach.

3. Painkillers, such as paracetamol and aspirin, relieve pain.

4. Useful drugs can be harmful or even fatal if they are used in the wrong way. Always follow the doctor’s
instructions and read the directions on the label carefully before taking any drugs.

Misuse of medicinal drugs
 Can be dangerous.
 Can cause harm to the body.

HARMFUL DRUGS

There are drugs that have harmful effects on the body when they are taken.
There are strict laws against the abuse of these drugs.
Examples: morphine, heroin, cannabis, sports drugs.

1. Morphine is a powerful painkiller.

 Made from juice of the unripe capsule of opium poppy.
 Too much morphine is harmful.

Page2

2. Heroin is the juice from an opium poppy, which can be changed into a powerful

drug.
 Is dangerous and can kill.
 The use of heroin is illegal in most countries.

Harmful effects of morphine and heroin on addicts;
 They become very tired.
 They lose their appetite.
 They become addicted to the drug, that is, they need to take more and more of it.
 It is usually injected into the blood using a syringe and needle.
When infected needles are shared between drug addicts, diseases such as HIV and hepatitis
are spread.

3. Cannabis (or Marijuana).

 Can cause harmful effects. It can;
o Cause headache,
o Damage muscles and the lungs,
o Cause brain damage when drug is used for a long time.

4. Methylamphetamine

 Most commonly abused drug in Brunei Darussalam.
 It is colourless and odourless solid which easily dissolves in liquids.
 Also known as ice due to its similar appearance to ice. Locally, it is known as syabu.
 Prolonged used of this drug has been linked to metal illness and occasional death from

heatstrokes, fits and heart attacks.
 Drug abusers show these signs and symptoms;

a) Increased breathing ad heart rate,
b) Dilated pupils, and
c) Loss of appetite.

Page3

Alcohol

Alcohol is also a drug that affects body processes. It can be found in drinks such as
beer, wine and brandy.
 Effects of abusive consumption of alcohol on the body:

 Immediate effects:
 Difficulty in balancing, walking and speaking.
 Slow down the body’s responses that may result in accidents.

 Long term effects:
 Damage to the liver and the heart.
 Stomach ulcers, pain and sickness.
 Death.

Page4

Tobacco

1. Tobacco is a product from leaves of the tobacco plant.
2. Tobacco smoke contains poisonous substances such as tar, nicotine

and carbon monoxide.

Tar damages the lungs; nicotine is addictive and can lead to heart disease; and carbon monoxide
reduces the ability of the blood to carry oxygen.

3. Tar is a _____________, sticky substance that build up in the lungs.

4. Tar causes the following effects;
a) Damages the cilia in the throat,
b) Damages the cells in the lugs (decreases the oxygen supply to the bloodstream),
c) Causes lung cancer.

5. ________________ is an addictive substance found in tobacco. This gives the smoker the urge to smoke
more.

Page5

6. Nicotine causes harmful effects such as;
a) Blood clotting,
b) Increased blood pressure,
c) Headaches,
d) Damage to the heart and blood vessels.

7. Carbon monoxide gas is a poisonous gas.
It reduces the capacity of blood to take in oxygen from the lungs.

8. Irritants
Cigarette smoke contains substances that irritate the cells in the lungs. This causes the smoker to
cough.

9. Prolonged smoking habits can lead to lung disease called emphysema.
This disease damages the lungs and makes the smoker fell breathless.

Page6

10. People who do not smoke but breathe in cigarette smoke are called ______________.

11. There are many diseases caused by active and passive smoking.

a) Cancer. Studies have shown that the more you smoke, the greater the risk of getting lung

cancer.

b) Chronic bronchitis

The cells in the main air passages to the lungs become inflamed.
Excessive mucus is secreted. This reduces the airflow in the passage and making breathing
difficult.

c) Emphysema.

Intense coughing cause the air spaces to enlarged decreases the surface area of the lungs. This
reduces the absorption of oxygen.

Page7

CHAPTER 9: DRUGS

TOPIC 9.1: THE USES AND ABUSES OF DRUGS
TOPIC 9.2: HARMFUL EFFECTS OF DRUGS

1. Antibiotics are drugs used to fight diseases caused by bacteria. TRUE / FALSE
(SPE/2012/Q42c) & (SPE/2016/Q42d)

2. Drug abusers addicted to methylamphetamine (syabu) can develop TRUE / FLASE
mental illnesses.
(SPE/2014/Q42b

3. Alcohol is a drug that slows down the body’s responses. TRUE / FALSE
(SPE/2011/Q42c)

4. Alcohol causes sharp visions. TRUE / FALSE
(SPE/2015/Q42c)

5. Anabolic steroids are useful drugs for athletes to improve their TRUE / FALSE
performances.
(SPE/2013/Q42a)

6. Passive smoking is breathing in the smoke from other people’s TRUE / FALSE
cigarette.
(SPE/2010/Q42c)

7. Passive smokers can get the effects like the heavy smokers. TRUE / FALSE
(SPE/2016/Q42a)

8. One of the most important pieces of advice given by doctors when prescribing antibiotics is for the
patients to finish them all. Why do we need to keep on taking the antibiotics until they are finished even
when we already feel better?
(SPE/2009/Q29)

A. To make sure that we do not waste the antibiotics.
B. To make sure that we will not fall ill again.
C. To make sure that other people will not mistakenly consume the antibiotics.
D. To make sure that all the bacteria are killed.

9. Complete the following passage using words provided below. Each word may be used once, or not at all.
(SPE/2010/Q41)

paracetamol alcohol marijuana resistant
antibiotics antacids addicted premature

Page8

A drug is a chemical substance which changes the way the body works. Most drugs are useful in preventing
diseases and stopping pain sensations. Drugs used to fight diseases caused by bacteria are called
____________________. When bacteria are not harmed by the drug anymore, they are said to become
____________________. A commonly used drug is ____________________ which relieves pain. An
example of a harmful drug is heroin. When people take harmful drugs and are unable to stop taking them,
they are said to be ____________________. Tobacco smoking also makes people unable to stop. When
pregnant women smoke, their babies may be born underweight, ____________________ or dead.
10. What are the effects of the following drugs on a human’s body?
(SPE/2015/Q25)

Cocaine Cannabis
Kill bacteria
A. Dry eyes and mouth Kill bacteria
B. Kill bacteria Loss of sensation
C. Kill bacteria Dry eyes and mouth
D. Loss of sensation

11. Which form of drug abuse will increase the risk of infection with HIV? (SPE/2016/Q26)

A. Cigarette smoking. C. Inhaling solvent fumes.
B. Drinking alcohol. D. Injection of heroin.

12. Which of the following consists of commonly abused drugs in sports? (SPE/2014/Q22)

A. Human growth hormone and cannabis.
B. Human growth hormone and steroids.
C. Methylamphetamine and heroin.
D. Methylamphetamine and steroids.

13. Alcohol is one of the most commonly abuse drugs. Which one of the following is not an effect of drinking
alcohol? (SPE/2010/Q26)

A. Causes lung cancer.
B. Causes stomach ulcers.
C. Damage the liver and the heart.
D. Diffiulty in balancing, walking and speaking.

14. Which of the following is an effect of alcohol on the body? (SPE/2012/Q30)

A. Increases a person’s responses. Page9
B. Increases a person’s ability to think clearly.
C. Reduces loss of body heat in a person.
D. Reduces self-control in a person.

15. Which statement is true of both heroin and excessive use of alcohol?
(SPE/2013/Q22)

A. Both can be taken by injection.
B. Both can cause harm to the body.
C. Both can increase the ability to think.
D. Both can speed up the body’s response.

16. Why does the consumption of alcohol increase the chance of having a car accident? (SPE/2014/Q23)

A. It causes slurred speech and heart attack.
B. It causes dry eyes and mouth.
C. It causes the body react slower.
D. It causes the body to react faster.

17. Which of the following drugs can be found in cigarettes?
(SPE/2013/Q21)

A. Heroin.
B. Morphine.
C. Nicotine.
D. Steroid.

18. Cigarette smoke contains many harmful substances. The three most harmful substances in cigarette
smoke are ________________________________.
(SPE/2009/Q30)

A. Tar, nicotine and carbon dioxide.
B. Tar, nicotine and carbon monoxide.
C. Tar, nicotine and nitrogen dioxide.
D. Tar, nicotine and nitrogen monoxide.

19. Which of the following diseases or conditions are caused by smoking tobacco?
(SPE/2011/Q20)
A. Bronchitis and stomach ulcers.
B. Damages to the liver and the heart.
C. Headaches and slowing down of the body’s responses.
D. Lung cancer and heart diseases.

20. Figure 1a and Figure 1b shows lungs of a non-smoker and smoker respectively. (SPE/2014/Q24)

Figure 1a Figure 1b Page10

Identify the substance in the tobacco smoke that causes the blackening of the lungs
shown in Figure 1b.
A. Carbon monoxide.
B. Irritants.
C. Nicotine.
D. Tar.

21. Study the graph in Figure below.
(SPE/2013/Q20)

Find the number of cigarettes smoked by a person who is at 50% risk of dying from lung
cancer.
A. 20 cigarettes.
B. 23 cigarettes.
C. 25 cigarettes.
D. 28 cigarettes.

Page11

22. The information in figure below was found on a packet of cigarette. Select two lung diseases caused by
cigarette smoking.
(SPE/2015/Q26)

A. Chronic bronchitis and influenza.
B. Chronic bronchitis and emphysema.
C. Emphysema and influenza.
D. Emphysema and hepatitis C.

23. Nicotine and tar are two of the harmful substance present in cigarette smoke. What are the effects of
nicotine and tar?
(SPE/2016/Q27)

Nicotine Tar

A. Lung cancer Damage the liver
B. Increased blood pressure Lung cancer

C. Increased blood pressure Loss of appetite

D. Loss of appetite Damage the liver

Page12

12

TOPIC 10: GASES

10.1 GASES IN THE AIR

1. The thin layer of air around the Earth is called the atmosphere.
2. Air is a mixture of gases.
3. The pie chart shows the composition of air by volume; (Nitrogen, 79%, Oxygen, 20%, Other gases, 1%

and Water vapour, varies).

Page13

Identifying for oxygen
Identifying carbon dioxide
Identifying water vapour

Page14

10.3 HYDROGEN Page15

 Hydrogen is the most common element in the universe.
 Hydrogen is the first element in the Periodic Table.

The properties of Hydrogen

 Colourless and odourless gas.
 Lightest among all substances.
 Less dense than air.
 Insoluble in water.
 Burns quietly with a pale blue flame.
 Explodes when it is ignited in oxygen.

The uses of Hydrogen

 Used as a fuel in space shuttles.
 Used to produce a very hot flame for cutting and welding metals. (This hot flame is produced when

hydrogen burns in oxygen).
 Used in the making of margarine.

Preparation of Hydrogen

1. When a metal reacts with acid, two new products are formed;
 Metal salt
 Hydrogen gas

In word equation:

++

2. The usual way of preparing hydrogen in a school laboratory is by the reaction of a reactive metal with a
dilute acid.

3. Examples of metal that can be used are magnesium, iron and aluminium.
Example:

Zinc + hydrochloric acid zinc chloride + hydrogen gas

Test for Hydrogen

A simple test for the presence of hydrogen:
o Ignite the unknown gas to be tested in air.
o If a ‘pop’ sound is heard, the unknown gas is
hydrogen gas.

Page16

CHAPTER 10: GASES

TOPIC 10.1: GASES IN THE AIR

1. Air consists of high percentage of nitrogen. TRUE / FALSE
(SPE/2013/Q42b)

2. Figure below shows the composition of air. What are Gas X and Y?
(SPE/2010/Q34)

Gas X Gas Y
A. Oxygen Nitrogen
B. Nitrogen Water vapour
C. Oxygen Hydrogen
D. Nitrogen Oxygen

TOPIC 10.2: PROPERTIES OF GASES

1. Water vapour turns dry cobalt chloride paper from pink to blue. TRUE / FALSE
(SPE/2009/Section B Q2d)

2. Complete the following passage by using the helping words provided. You may use the word once, more
than once or none at all.
(SPE/2016/Q41)

mixture 0.05% orange compounds oxygen
glowing lighted nitrogen white 1%

Air is a ____________________ of gases. The constituents in air are 79% of nitrogen, 20% of oxygen,
0.03% of carbon dioxide, ____________________ % of noble gases and water vapour. The proportion of
water vapour in the air varies from place to place. Noble gases are unreactive gases. Other unreactive gas
present in the air is ____________________. The presence of oxygen will rekindle a
____________________ splint. The presence of carbon dioxide can be tested using lime water. The lime
water forms a ____________________ precipitate when carbon dioxide is present.

Page17

3. The pie-chart in Figure below shows the percentages of four gases in the atmosphere. (SPE/2011/Q31)

Gas P Gas Q Gas R
A. Clear lime water turns Relights a glowing splint Blue cobalt chloride
paper turns pink
chalky Blue cobalt chloride paper Clear lime water turns
B. Relights a glowing splint turns pink chalky
Clear lime water turns Relights a glowing splint
C. Blue cobalt chloride chalky
paper turns pink Relights a glowing splint Produces a ‘pop’ sound
with a burning splint
D. Blue cobalt chloride
paper turns pink

4. Khairul carried out three tests shown in figure below to determine the identity of gas Q.

What is gas Q?
(SPE/2015/Q28)

A. Carbon dioxide.
B. Hydrogen.
C. Nitrogen.
D. Oxygen.

Page18

5. Three tests were carried out on a colourless gas and the results are shown in Figure below.
(SPE/2012/Q29)

Gas P Gas R
1. Glowing splint Glow is extinguished (goes out)
2. Lime water Does not turn lime water chalky
3. Cobalt chloride paper
Changes from blue to pink

From the observations, it can be concluded that the gas is _____________.

A. carbon dioxide.
B. hydrogen.
C. oxygen.
D. water vapour.

6. The cobalt chloride paper shown in Figure below is used to test for the presence of water vapour. Which
colour change best describes the presence of water vapour? (SPE/2014/Q25)

A. Blue  Pink
B. Blue  Pink
C. Pink  Blue
D. Red  Blue

7. Which of the following noble gases is commonly used in colourful advertisement signs?
(SPE/2009/Q25)

A. Argon. C. Xenon.
B. Neon. D. Helium

8. Figure below shows a gas jar containing gas Y. And Gas Y is a noble gas. Which statement about Y is
correct.
(SPE/2015/Q27)

A. Y makes up 79% of air.
B. Y is unreactive.
C. Y relights a glowing splint.
D. Y supports combustion.

Page19

9. Helium gas is used in party balloons as shown below.
(SPE/2013/Q44cii, iii & iv)

a) Draw what happens to the party balloon filled with helium after one day.

b) What has happened to the helium as inside the balloon after one day?

________________________________________________________________________
c) State a reason why helium is a suitable gas to be used in party balloons.

________________________________________________________________________

TOPIC 10.3: HYDROGEN

1. When an acid is added to a metal such as magnesium, oxygen is produced.

(SPE/2016/Q42e) TRUE / FALSE

2. Hydrogen gas was collected in a test tube in figure below. A burning splint was put inside the test tube.
On carrying out this test, droplets of liquid B were formed on the sides of the test tube. A piece of cobalt
chloride paper was used to test for liquid B.

Page20

Which observations correctly describe these tests? (SPE/2013/Q23)

Hydrogen Liquid B
A. A pop sound produced Cobalt chloride paper turned blue to
pink
B. A pop sound produced No changed observed

C. The burning splint relighted Cobalt chloride paper turned blue to
D. The burning splint relighted pink
No changed observed

3. Most metals react with dilute acids. Figure below show the preparation of hydrogen gas using the
reaction of metal, magnesium, with an acid, dilute hydrochloric acid. (SPE/2012/Q45)

i. Complete the word equation for the reaction of magnesium with dilute hydrochloric acid.

Magnesium + dilute + Hydrogen
hydrochloric ____________
acid

ii. Name another suitable metal that could be used to prepare hydrogen gas.

________________________________________________________________________

iii. Describe a test to show the presence of hydrogen gas.

________________________________________________________________________

4. Figure below shows the preparation of hydrogen gas in the laboratory. (SPE/2014/Q41)

Page21

Complete the following passage by using the helping words provided.

acids alkalis zinc lighted glowing
ethanol relight margarine light water

Hydrogen gas is prepared by the reaction of metals and ______________. Examples of metals that can
be used to prepare hydrogen gas are __________________, magnesium and iron. The presence of
hydrogen gas is tested by using ________________________ splint. A pop sound shows that hydrogen
is present. On carrying out this test, droplets of _____________________ are formed. Hydrogen gas is
used as a fuel, weather balloon and manufacture of __________________________.

Page22

TOPIC 11: TRANSPORT SYSTEM IN HUMANS

TRANSPORT IN MAMMALS

1. Mammals are multi-cellular organisms – they are made up of many living cells.
Most of these cells are situated far away from the mammals’ body surfaces and from one another.
Diffusion is too slow to bring materials into, around and out of the body.

2. That is why it is important for mammals to have an efficient transport system so as;

 To supply oxygen and food quickly to all parts of the body.
 To remove carbon dioxide and other waste matter from the cells.

3. The transport system in mammals is called the blood circulatory system.
4. The diagram below shows the human circulatory system.

The human circulatory system is made up of the heart and the blood vessels.

Page23

11.1 STRUCTURE OF THE HEART Page24
1. The heart:
 Is about the size of a fist.
 Is made up of muscles.
 Has four chambers:
 Two upper chambers: right atria and left atria.
 Two lower chambers: right ventricle and left ventricle.
 Contracts to pump blood out and relax to allow blood to enter.
 Pumps blood around the body.

I. On the left side of the heart, the chambers have blood rich in oxygen (oxygenated blood) and on the right
side, the chambers have blood with less oxygen and more carbon dioxide (deoxygenated blood).

II. The left ventricle has a thicker wall than the right ventricle.
This is because it needs to exert a larger force in order to push blood to all parts of the body.

III. The valves in the chambers prevent the blood from flowing backwards. Page25
This ensures that the blood flows in one direction.

2. Blood circulation:
The diagram shows the circulation (movement) of the blood around the body.
As the blood circulates around the body, it passes the heart twice.
This is called double circulation.

11.2 BLOOD

 The human body has about five (5) litres of blood.
 Carries nutrients (from the small intestine) and oxygen (from the lungs) to every cell in the body.
 Allows carbon dioxide (from the respiration of the cells) to diffuse and carries it back to the lungs.
 Carries other waste matter (such as urea) to the kidneys for removal.

 Blood contains: red blood cells, white blood cells, platelets and plasma.

Microscopic image of a blood sample;

Page26

Red blood cells Page27
 Biconcave shape
 Have no nucleus

White blood cells
 Larger than red blood cells
 Fewer in number
 WBC protect the body against infections and diseases.

Plasma
 Plasma is a light yellow liquid, containing mainly water.
 Many substances such as nutrients are dissolved in it.
 Red blood cells, white blood cells and platelets are suspended in plasma.

Platelets
 Less than 1% of blood is made up of platelets.
 When there is a cut in the skin, platelets group together at the cut and this causes blood to clot.
 This prevents further bleeding and allows the skin to start healing.
3. The blood vessels:
 Carry blood around the body, consists of:
 Arteries,
 Veins,
 Capillaries.

 The arteries carry blood away from the heart to other parts of the body.
 The veins carry blood back to the heart.
 The capillaries connect the arteries to the veins. They are tiny, thin-walled blood vessels where exchange

of useful and waste substances takes place.

Pulmonary artery: Pulmonary vein: Page28

Carries blood from Returns blood from
the heart to the the lungs to the
lungs. heart.

Vena cava: Aorta:

Collects blood and Carries blood to all
returns it to the heart. parts of the body.
Blood flows slowly and Blood flows very fast
at low pressure. and at high pressure.

The valves in the veins The artery branches
prevent the backflow out, ending at fine
of blood. capillaries among the
body cells.

4. A heartbeat is often described as ‘lub-dub’ sound heard when one
places a stethoscope at the chest area.
The average normal heartbeat rate of an adult is about 72 times per
minute.

5. Each time the heart pumps, a wave of blood flows along the arteries.
This wave is called a pulse. One can feel his or her pulse at the wrist.
The number of pulses per minute is called the pulse rate.

6. As blood flows along the arteries, it pushes on the walls of the arteries. This push exerts a force
called the blood pressure.
The more the heart pumps with force, the blood pressure increases.

7. During exercise, cells require more energy. The heart beats faster to allow nutrients and oxygen to
reach the cells faster.

Page29

CHAPTER 11: TRANSPORT SYSTEM IN HUMANS

TOPIC 11.1: STRUCTURE OF THE HEART

1. Valves found in the heart and veins ensure blood flows in forward and backward directions.
TRUE / FALSE

(SPE/2009/Section B Q1c)

2. The pulmonary artery carries oxygenated blood from the heart. TRUE / FALSE
(SPE/2013/Q42e)

3. The vena cava is connected to the right atrium of the heart. TRUE / FALSE
(SPE/2014/Q42c)

4. The valves in the heart chamber prevent blood from flowing TRUE / FALSE

backwards.
(SPE/2015/Q42d)

5. Figure below shows the structure of a human heart with the main blood vessels. Which blood vessel
transports blood from the heart to the lungs?
(SPE/2009/Q23)

6. Figure below shows the structure of the heart. Which structure of the heart exerts a larger force to
pump blood to all parts of the body?
(SPE/2014/Q26)

Page30

7. Figure below shows the structure of the human heart. What is the main function of C? Page31
(SPE/2010/Q25)
A. To filter the blood.
B. To make blood flow faster.
C. To prevent blood from flowing backwards.
D. To prevent the mixing of blood.

8. Figure below shows blood vessels carrying blood to and away from the heart. Which of the following
blood vessels carry oxygenated blood?
(SPE/2012/Q38)
A. 1 and 2.
B. 1 and 3.
C. 2 and 4.
D. 3 and 4.

9. Which diagram shows a correct sequence of the flow of blood in the circulatory system?
(SPE/2014/Q27)

10. The blood flowing in the pulmonary vein is different from the blood flowing in other veins because the
blood in the pulmonary vein is ____________________. (SPE/2011/Q33)
A. moving away.
B. moving to the lung.
C. poorer in oxygen.
D. richer in oxygen.

11. Figure below shows the human blood circulatory system. Why is the human circulatory system known as Page32
‘double circulation’?
(SPE/2009/Q34)
A. Blood travels to each organ twice.
B. The heart pumps twice in each circulation.
C. The blood passes the heart twice in each circulation.
D. The blood travels in two different types of blood vessels.

12. The diagram in Figure below shows the systems present inside a human being. (SPE/2013/Q45)

a) Name the system labelled A and B.
A - ____________________________________________________________________
B - _____________________________________________________________________

b) In system A, name the blood vessel where blood rich in oxygen flow to all parts of human body.
________________________________________________________________________

c) In system B, name two important gases that are going in and out through this system.
Gas going in - _____________________________________________________________
Gas going out - _____________________________________________________________

TOPIC 11.2: BLOOD
1. Which of the following is a type of blood vessel? (SPE/2015/Q29)

A. Trachea
B. Oesophagus
C. Intestine
D. Vein

2. Which of the blood vessel(s) in Figure below carry blood away from the heart under high pressure?
(SPE/2013/Q24)

A. 1 only.
B. 1 and 2.
C. 2 and 3.
D. 1, 2 and 3

3. Figure below shows the various components of blood in a blood vessel.

Identify the type of blood vessel and the components of the blood present in Figure above.
(SPE/2014/Q28)

Type of blood vessel Blood components
A. Artery red blood cells, plasma, platelets
B. Artery white blood cells, plasma, platelets
C. Capillary red blood cells, plasma, platelets
D. Vein white blood cells, plasma, platelets

4. Figure below shows the components of blood.
(SPE/2013/Q25)

Identify component X, Y and Z. Y Z Page33
White blood cell Platelets
X White blood cell
A. Plasma Plasma Plasma
B. Platelets White blood cell Platelets
C. Platelets
D. White blood cell Element

5. Figure below shows one type of blood cell. What is the name of the blood cells and its function?
(SPE/2010/Q37)

Name Function
Transports food
A. Red blood cell Transports oxygen
B. Red blood cell Transports food
C. White blood cell Transports oxygen
D. White blood cell

6. Figure below shows four components of blood. Which component helps carry oxygen throughout the
body? (SPE/2015/Q31)

7. The graph in Figure below shows the results of an investigation to find the effects of exercise on the
pulse rate of some Year 8 students. (SPE/2014/Q29)

Use the graph to predict the pulse rate of the students 20 minutes after the exercise. Page34

A. 50 – 52
B. 70 – 72
C. 90 – 92
D. 120 – 122

8. Table below shows information about the lifestyle of four 50 year old adults. Which adult is likely to have
a healthy heart?
(SPE/2015/Q30)

Adult Exercises regularly Eats balanced diet Smokes cigarettes
(Age 50)
X X /
A. / / X
B. X / /
C. / X X
D.

9. a) Figure below shows the structure of a human transport system.
(SPE/2016/Q46a)

i. Which blood vessel A, B, C or D carry blood containing high concentration of oxygen?
_____________________________________________________________________

ii. Why is the wall of left ventricle thicker than right ventricle?
_____________________________________________________________________

Page35

b) Figure below shows the cross section of two blood vessels, an artery and a vein.
(SPE/2016/Q46b)

i. From figure in question 9a), use letters A, B, C or D to group the different types of blood vessels
under:
Arteries: ____________________ and ____________________

Veins : ____________________ and ____________________

ii. Based on figure above, explain two differences between an artery and a vein.
__________________________________________________________________

__________________________________________________________________

iii. Explain why the heart beats faster during a vigorous exercise.
__________________________________________________________________

__________________________________________________________________

10. Saiful recorded the heartbeats of his friend, Nabil for doing three activities as in the Table below.
(SPE/2013/Q48)

Time / s Sitting Number of heart beats per min Running
0 68 Walking 68
60 68 68 105
120 68 Y
180 68 X 180

88

98

a) Plot a graph of heart beats per minutes against time for sitting, walking and running activities on the Page36
same axes provided below.

b) From the graph, find the values of X and Y.
X – _______________________________
Y –________________________________

c) Table below shows the calories burnt when doing the three activities.

Sitting Walking Running

Calories burnt 0 24 52

How are the activities related to the calories burnt?
________________________________________________________________________

Page37

UNIT 12: PLANT AND ANIMAL NUTRITION

12.1: PHOTOSYNTHESIS

1. Photosynthesis is a process by which plants manufacture food using carbon dioxide and water in the
presence of sunlight and chlorophyll.

2. The word equation for photosynthesis:

RAW MATERIALS & CONDITIONS NECESSARY FOR PHOTOSYNTHESIS

Page38

12.2: FOOD AND ITS IMPORTANCE

1. Plants are:

a) Living organisms that produce their own food.

b) Most important source of food for most living things.

2. We need food for:

a) Repair worn out tissue

b) Maintain a healthy body

c) Grow new cells and tissues

d) Provide us with energy for our daily activities

3. Food that we eat may be grouped as follows:

i. Proteins

ii. Carbohydrates

iii. Fats All foods are
iv. Fibre nutrients EXCEPT
v. Vitamins water and fibre

vi. Mineral salts

vii. Water

PROTEINS

1. Proteins are one of the basic building blocks of the human body, making up about 16% of our total

body mass.

Page39

2. Deficiency of proteins may lead to a disease known as kwashiorkor, which causes swollen abdomens.

CARBOHYDRATES
1. Carbohydrates are the principle source of energy in most humans. It provides between 40–80 % of total

energy intake in different populations.
2. Sugars and starch are examples of carbohydrates.

Page40

FATS
1. Fats provide almost twice as much energy as proteins and carbohydrates.

FIBRE
1. Fibre is obtained from plant materials.
2. Fibre cannot be digested and will be passed out of the body.
3. Fibre absorbs water, making the waste matter soft, preventing constipation.

4. Constipation is the result of eating too little fibre and causes faeces to become
dry and hard, making it difficult to expel from the body.

Page41

VITAMINS

Page42

MINERAL SALTS

Page43

WATER
1. Fruits such as watermelon contain a lot of water.

FOOD TEST
Testing food for the presence of starch, glucose, fats and proteins.

A. Biuret Test (Test for protein)

B. Test for starch

Page44

C. Test for glucose
D. Test for oil
E. Test for fats

Page45

12.3 BALANCED DIET

1. A balanced diet contains the correct proportion of proteins, carbohydrates, fats, vitamins, mineral salts,
fibre and water.

2. Eating a balanced diet is important for all individuals.
3. Each individual has different nutritional needs.
4. A balanced diet for one person may not be balanced for another.
5. HEALTHY PLATE’ portion or the food pyramid are two main ways to ensure that your meal is a

balanced diet.

‘HEALTHY PLATE’ portion

Page46

THE FOOD PYRAMID

Page47

AN UNBALANCED DIET Page48
1. A diet consisting of too much or too little of a particular type of food is an unbalanced diet. It does not

supply the right amounts of nutrients needed and often leads to malnutrition.
2. The effects of an unbalanced diet include:

• obesity,
• diabetes,
• underweight, and
• developing coronary heart diseases.

Obesity
When a person regularly eats too much of carbohydrates and fats and does not exercise enough, he or she
will become overweight.
Diabetes
Diabetes is a disease caused by high levels of sugar in the blood.
Underweight
When the amount of food that a person takes in is much less than what is required daily, he or she may
weigh less than the expected weight of a healthy person.
Coronary heart diseases
A diet that contains a large amount of fats may lead to coronary heart disease.

Teenagers need more energy than the elderly.

12.4 DIGESTION IN MAMMALS

A. MASTICATION
What is mastication?
Chewing action by the teeth which breaks down large pieces of food into smaller pieces.

B. WHY MUST FOOD BE DIGESTED?
1. The cells of our body need food for growth and energy.
2. Food contains carbohydrates, proteins and fats.
3. Carbohydrates, proteins and fats are made of large and complex particles.
4. Only small and simple particles can pass through the cell membranes into the cell.
5. So, the food we eat must be broken down.

Page49

ENZYMES
• Our body produces enzymes.
• They speed up the process of digestion.
• The enzymes involved in the digestion of food are carbohydrase, protease and lipase.
• Each enzyme acts on specific food.

Page50