Focus SPM KSSM 2021 Tingkatan 5 - Science

PELANGI BESTSELLER

SCIENCE SPM

5Form

KSSM

Kee Bee Suan • Chong Kum Ying D ual L anguage
Zuraini binti Abdul Razak (Guru Cemerlang) P rogramme

Mak Sew Yin • Lau Pik Ying NEW SPM ASSESSMENT
Nilavathi Balasundram
FORMAT 2021

Format: 190mm X 260mm TP Focus F5 Sc BI pgi_CRC

SCIENCE SPM

Kee Bee Suan 5Form
Chong Kum Ying
Zuraini binti Abdul Razak (Guru Cemerlang) KSSM
Mak Sew Yin
Lau Pik Ying
Nilavathi Balasundram

© Penerbitan Pelangi Sdn. Bhd. 2021
All rights reserved. No part of this book may be
reproduced, stored in a retrieval system, or transmitted in
any form or by any means, electronic, photocopying,
mechanical, recording or otherwise, without the prior
permission of Penerbitan Pelangi Sdn. Bhd.

ISBN: 978-967-2965-67-1
eISBN: 978-967-2965-82-4 (eBook)

First Published 2021

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CONTENTS

1Chapter Microorganisms 1

1.1 World of Microorganisms 2
1.2 Useful Microorganisms 14
1.3 Prevention and Treatment of Diseases Caused by Harmful Microorganisms 17
21
SPM Practice 1

2Chapter Nutrition and Food Technology 24

2.1 Balanced Diet and Calorific Value 25
2.2 Nutrient Requirements in Plants 31
2.3 Nitrogen Cycle 35
2.4 Food Production Technology 37
2.5 Food Processing Technology 41
2.6 Health Foods and Health Supplements 45
SPM Practice 2 48

3Chapter Sustainability of the Environment 53

3.1 Product Life Cycle 54

3.2 Environmental Pollution 59

3.3 Preservation and Conservation of the Environment 64

SPM Practice 3 68

4Chapter Rate of Reaction 72

4.1 Introduction to Rate of Reaction 73

4.2 Factors Affecting Rate of Reaction 78

4.3 Applications of the Concept of Rate of Reaction 88

SPM Practice 4 92

iii

5Chapter Carbon Compounds 96

5.1 Introduction to Carbon Compounds 97

5.2 Hydrocarbons 99

5.3 Alcohol 104

5.4 Fats 111

5.5 Palm Oil 113

SPM Practice 5 123

6Chapter Electrochemistry 128

6.1 Electrolytic Cell 129

6.2 Chemical Cell 141

SPM Practice 6 145

7Chapter Light and Optics 147

7.1 Formation of Images by Lenses 148

7.2 Optical Instruments 155

SPM Practice 7 161

8Chapter Force and Pressure 165

8.1 Pressure in Fluids 165

SPM Practice 8 175

9Chapter Space Technology 179

9.1 Satellite 180

9.2 Global Positioning System (GPS) 187

SPM Practice 9 190

SPM MODEL PAPER 192

ANSWERS 203

iv

8Chapter Force and Pressure

CHAPTER FOCUS How does the pressure in fluids occur? Chapter
Besides the application in the hydraulic system as
Pressure in Fluids shown in the photograph above, state another 8
application that you know.
What is the principle that explains the relation
between fluid velocity and pressure?
Can you state some examples about the application
of Pascal’s principle and Bernoulli’s principle in
daily life?

165

  Science Form 5 Chapter 8  Force and Pressure 4. Transmission of fluid-pressure is stated in
Pascal’s Principle.
8.1 Pressure in Fluids
5. Pascal’s principle is introduced by Blaise
1. Pressure is defined as the amount of force Pascal, a French mathematician and physicist.
exerted per unit surface area.
Blaise Pascal
2. Force is a pull or push acting on certain
objects. 6. Pascal’s principle states that the pressure
exerted on a fluid in an enclosed system
3. Fluids are substance that can flow and take on can be uniformly transmitted to each part
the shape of their containers. of fluid.

4. Air, gas, liquid and water are fluids. 7. Liquids cannot be compressed thus enables
Concept of Pressure in Fluids in an Enclosed transmission of pressure in water to all
System direction.

1. Pressure exerted on liquids can be transmitted Hydraulic System
from one point to another point because the
ability of liquids to flow. 1. The transmission of pressure in liquids can be
applied in the operation in hydraulic system.
2. Figure 8.1 shows the transmission principle of
pressure in liquids. 2. Figure 8.2 shows a simple hydraulic system.

Push Input Load Large
force piston
X Output
Small force
AG piston
BF
Liquid
C DE
Chapter Figure 8.2  Hydraulic system
Figure 8.1  Transmission of pressure in liquids
(a) A small input force applied to the small
(a) Referring Figure 8.1, the pull force on the piston produces a large output force on
plunger produces pressure on the surface the large piston.
of water at X.
(b) As stated in the Pascal’s principle, the
(b) Water spills out from each hole to all pressure exerted on fluids in an enclosed
direction with the same speed. system can be uniformly transmitted to
each part of the fluid.
(c) This shows that pressure exerted on
the surface area of water at X can be

8 transmitted to points A, B, C, D, E, F and
G.
3. The pressure in fluids can be uniformly
transmitted in all direction, causing the water
to spill out in all direction.

166

Science Form 5 Chapter 8  Force and Pressure

Therefore, Pressure = Force
Surface area
Pressure applied = Pressure applied
to small piston to large piston

Example 8.1 Solution:
Figure 8.3 shows a simple hydraulic system. (a) Pressure applied to liquid by piston A

20 N Load 20 N
Piston A = 0.05 m2
Fluid Piston B = 400 N m–2

Figure 8.3 (b) Pressure applied to piston B
= pressure applied on the liquid by piston A
The surface area of pistons A and B are 0.05 m2 and = 400 N m–2
0.5 m2 respectively. If a force of 20 N is applied to
piston A, calculate (c) Force applied to load by piston B
(a) The pressure exerted on the liquid by piston A. Force
(b) The pressure applied to piston B.
(c) The force applied to load by piston B. 0.5 m2 = 400 N m–2

Force = 400 N m–2 × 0.5 m2

= 200 N

3. From the example above, it clearly states SPM Highlights
that a small force applied to small piston can
produce a great force on large piston. The figure shows a simple hydraulic system.

4. Therefore, hydraulic system is very useful to Force Load (400 N)
function as a force multiplier. Piston A Piston B
(0.01 m2) (0.8 m2)

Fluid

Example 8.2

A force of 20 N is needed to uplift a load of 1000 n, What is the force needed by piston A to balance the
what is the ratio of surface area of small piston to
the surface area of large piston? load of 400 N?

(Use pressure = force )
surface area
Solution:
A 4 N
Force applied to Force applied to B 5 N
C 320 N
small piston = large piston D 200 N
Surface area of small Surface area of large

piston piston Chapter

Ratio of surface area of small piston to the surface Examiner’s Tip = 400 N 8
area of large piston Force applied to small piston 0.8 m2
0.01 m2
Force applied to small piston
= Force applied to large piston Force applied to small piston
= 20 N : 1000 N = 400 N × 0.01 m2

= 1 : 50 0.8 m2
=5N

Answer: B

167

  Science Form 5 Chapter 8  Force and Pressure

EkAscpteivriimtye8n.12.1

Aim: To investigate the effect of transmission of pressure in fluids.

Problem statement: What is the effect of transmission of pressure in hydraulic system?

Operational definition: The load weight used on each piston shows the magnitude of applied force.

Materials: Load of 10 g, 100 g, 200 g and 300 g

Procedure:

Load (10 g) Load (100 g)
Small piston Small syringe

Small syringe Large syringe

Water

Rubber tube

Figure 8.4 Apparatus set-up

1. The apparatus is set-up as shown in Figure 8.4.
2. Load of 100 g is put on the large piston. Several loads of 10 g is put on the small piston until both pistons

are at the same level.
3. Step 2 is repeated by putting the load of 200 g to replace the load of 100 g and then the load of 300 g on

the large piston.
Results:

Weight on large piston (N) Weight on small piston (N)
1 0.2
2 0.4
3 0.6

Chapter Remarks:
• The load weighing 1 kg is 10 N
• The result depends on the surface of pistons in large syringe and small syringe

Discussion:
1. The result shows that the small weight can be placed on small piston to support the heavy weight on large

8 piston.
2. Based on the results, we can conclude that a small input force can be applied to small piston to produce a
great output force on the large piston.
Conclusion:
A small input force applied on the small piston can produce a great output force on the large piston.

168

5. There are four basic principles of hydraulic Science Form 5 Chapter 8  Force and Pressure
system such as:
• Liquid has no shape 3. The examples of machines that operates based
Liquids which can take on the shape of on hydraulic system are:
their containers, enables to transmit force (a) Hydraulic jack
applied in the hydraulic system with (b) Hydraulic brake
complex design. (c) Garbage bin lift
(d) Power steering
(e) Excavator
(f) Dental chair

(a) Mesin pengorek (b) Kerusi di klinik pergigian

Figure 8.5 (a)  Excavator (b) Dental chair

• Liquids are incompressible Figure 8.6  Machines operating based on hydraulic
In hydraulic system, there is liquids that system principle

cannot be compressed in the containers. Hydraulic jack
The pressure applied on the liquids will
be transmitted from one place to another 1. Figure 8.7 shows the structure of a hydraulic
based on the total force applied upon the jack. A hydraulic jack is used to lift up a car.
liquids.
Reservoir Load Large
• Transmit pressure to all direction Small piston piston
Pascal’s principle is used in hydraulic Small cylinder Large
Control valve cylinder
system that requires the transmission of
pressure to all parts in one time. Fluid

• Able to conduct heavy work Figure 8.7  Hydraulic jack structure
Hydraulic system has the ability to
2. By using hydraulic jack, a person can lift up Chapter
conduct heavy work even though built in easily the cars. When a small input force is
small size. Small in size saves the usage applied on the jack handle, a larger output 8
of hydraulic fluids in the system. force is produced to lift up the cars.

Application of Pascal’s Principle in Daily
Life

1. Hydraulic system is used as multiplier force.

2. The system is beneficial specially to carry or
lift heavy load.

169

  Science Form 5 Chapter 8  Force and Pressure Relationship between Fluid Velocity and
Pressure
Hydraulic brake
1. Daniel Bernoulli (1700 – 1782) is a physicist
1. Figure 8.8 shows a simplified structure of a and mathematician whose gives the major
hydraulic brake. contribution in the field of mechanics of
fluids.
Main
Brake pedal cylinder

Piston Brake
oil

Brake shoe

Brake cylinder Brake

Figure 8.8  Car hydraulic brake structure Daniel Bernoulli

2. When the driver presses the brake pedal that 2. His name is commemorated in the Bernoulli’s
is connected to the piston in the main cylinder, principle.
a pressure is applied to the brake oil.
3. Bernoulli’s principle states that as the speed
3. The pressure will transmit through the brake of the moving fluid increases, the pressure
oil to four brake cylinders on each wheel. within the fluid decreases.

4. A large output force is produced. This makes 4. Conversely, as the speed of the moving
the brake cylinder piston to press the brake fluid decreases, the pressure within the fluid
shoe on the wheel and hence friction slows increases.
down the car.
SPM Tips
Dental chair
It states that ‘as the velocity of fluid increases, the
1. Figure 8.9 shows the structure of a dental pressure decreases, is less accurate because the
chair using the hydraulic system. Bernoulli’s principle explains about “causes and
consequences” rather than relation.

5. Figures 8.10 and 8.11 describe about

Bernoulli’s principle.

(a) High Medium
high
pressure Low pressure

Pedal pressure

Large Water B Water
piston flows Fast
Chapter A C flows
in out

Slow Slow

Small piston Figure 8.10

8 Figure 8.9 Dental chair structure (i) Observe the changes in pressure that
happens when water flows through
2. When the small piston is pressed, a pressure different diameters (known as Venturi
is applied onto the fluid and uniformly tube).
transmitted to the large piston.
(ii) Pressures at points A, B and C are
3. An output force is produced and pushes the shown by the height of water in the
chair up. tube.

170

(iii) When water is forced to flow through Science Form 5 Chapter 8  Force and Pressure
a tube with convergent section at B
(narrow throat) the velocity increases. 7. The relationship between the flow of velocity
and pressure in fluids can also be obtained
(iv) When the speed of water increases, through observation and inferences on the
the pressure at point B decreases. occurrence of storm.

(b) XY Z Low Low
pressure pressure

High
pressure

Water Figure 8.13 Movement of air

Figure 8.11 (a) The strong wind moves in high speed on
top of the roof whereas the air inside the
(i) The water level in tube X is higher house moves in calm.
than the water level in tube Y and
water level in tube Y is higher than (b) According to the Bernoulli’s principle,
the water level in tube Z. the higher the velocity, the lower the
pressure.
(ii) This shows that the pressure at point
X is the highest and the pressure (c) Therefore, the pressure inside the house is
at point Z is the lowest. It happens higher compared to outside of the house.
because the velocity of water
increases when the water flows (d) The difference in the pressure produces
further from the water tap. lift force that is strong enough to blow
away the house roofs.
6. The velocity of air also affects pressure. The
activity showing the Bernoulli’s principle is Application of Bernoulli’s Principle in Daily
as in Figure 8.12. Life

Original Aeroplane
position
of paper Lift
force • High velocity of moving air
Air • Low pressure

Figure 8.12 • Low velocity of moving air Chapter
• High pressure
(a) When air is blown hardly across the
top surface of a piece of paper which is (a) Aerofoil-shaped wings
held below the mouth, the paper is lifted
upwards. 8

(b) The flow of air with high velocity reduces Air flow
the air pressure on top of the paper. Wing

(c) The higher atmospheric pressure at the
bottom of the paper pushes the paper
upwards.

(b) Air flows through the aeroplane wings
Figure 8.14 Aerofoil-shaped wings of aeroplane

171

  Science Form 5 Chapter 8  Force and Pressure 11. The aeroplane will start to fly in the air.

1. An aeroplane wing has a curved upper surface 12. The lift force must be same as the gravity
and a flatter bottom surface. This shape is force, and the thrust must be same as the drag
known as aerofoil. to maintain the uniform speed at certain level.

2. When the aeroplane moves forward, air flows 13. Angle of attack of aerofoil also contributes in
at higher speed at the curved upper surface lift force.
of the wings compared to the flatter bottom
surface. <␣ Angle of attack

3. As a result, the air pressure at the upper Flying direction
surface of the wing is low and the air pressure
at the bottom surface is high. Figure 8.16 Angle of attack

4. As an aeroplane moves in higher speed, the 14. By increasing the angle of attack, the lift force
larger is the difference of air pressure between will be increased.
both wings.
Helicopter
5. The difference in pressure produces a force
on the wings and lift up the aeroplane. This is 1. Unlike aeroplane, helicopters can hover and
known as lift force. move forward.

6. When magnitude of lift force produced 2. Helicopters move by spinning the rotors in
exceeds the gravitational force, the aeroplane aerofoil shape.
will take off from the runway.
Rotor blades
7. There are four types of forces that act upon an
aeroplane, as shown in Figure 8.15. Tail rotor
bladers
Lift force
(due to difference in the pressure
at upper surface and bottom surface of wings)

Thrust Drag

(generated (due to air
by engine) resistance)

Chapter Weight Figure 8.17  A helicopter and its rotor blades
(due to gravitational pull)
3. When the rotor blades spin fast, the lift force
Figure 8.15  Four types of forces that act upon an will be produced to allow the helicopter to
aeroplane take off.

8. In the beginning, the engine provides a thrust 4. The tail rotor blades at the back part of the
to the aeroplane, resulting in a forward force. helicopter work to stabilise the helicopter in
the air.
8 9. If the thrust is larger than the drag, the
aeroplane will move forward.

10. When the speed of the aeroplane increases
until exceeding a level, the lift force will be
more than the gravitational pull.

172

Drone Science Form 5 Chapter 8  Force and Pressure

causes the difference in the air speed and
pressure as shown in Figure 8.20(b). This
difference resulting in the difference in air
pressure that produces a net force to pushes
the ball to the side. Therefore, the ball travels
in a curved path.

Figure 8.18  Drone (a)

1. The four propellers on drones change • Spinning of a ping pong ball causes
movement to lift force the airflow rate to decrease

2. Due to propellers with aerofoil shape, the • Pressure increase
air pressure at upper part is less than the air
pressure at the bottom part when they are Flying V
moving, thus produces lift force. direction

Bunsen Burner Spinning

1. (a) Based on the Bernoulli’s principle, the Net force, F • Spinning of a ping pong ball
fast-moving gas stream from the nozzle causes the airflow rate
causes gas pressure in the tube is less to increase
than the atmospheric pressure.
• Pressure decrease
(b) The difference in pressure causes air to be
drawn into the tube and mixes with gas to (b)
enable combustion.
Figure 8.20
Flame

Atmospheric Higher speed, Playing football
pressure lower pressure
1. A football player can execute a kick, sending
Lower speed, Nozzle the ball in a curved path by spinning.
higher pressure

Air flow

Gas

Figure 8.19 Bunsen burner Chapter

Playing table tennis 8

1. Figure 8.20(a) shows a table tennis player (a)
making a rotating ball pass while moving
forward. This causes the ball to spin as it
moves forward. The spinning of the ball

173

  Science Form 5 Chapter 8  Force and Pressure 1. We need to stand behind the yellow safety line
High air pressure when waiting for the train at the platforms.

Movement Spinning 2. This is because if the train travels at high
path of ball speed, the air surrounding the train platform
will also travel in high speed, therefore,
Low air pressure when the velocity increases, the pressure will
(b) decrease.

Figure 8.21  3. When the pressure decreases, a person
standing nearby the rail track will get pulled
Safety line towards the train.

Designing a Tool using a Principle of
Pressure in Fluids

1. The hydraulic system work by transmitting
pressure through fluids to move an object.

2. Figure 8.23 shows some examples of tool
design that lift up objects using hydraulic
system

Figure 8.22 Safety line (yellow lines) at rail
station platform

Green Lift
System
VIDEO

Figure 8.23 Examples of tool design using the application of hydraulic

Chapter Checkpoint 8.1

8 Q1 When the water tap is broken, why the water spilled out in all direction?
Q2 State the pressure transmission principle in fluids.
Q3 State three examples of machines operating based on hydraulic systems.
Q4 Draw a diagram to show four types of force that act on a moving aeroplane.

174

CONCEPT MAP Science Form 5 Chapter 8  Force and Pressure
Pressure in Fluids

Pascal’s principle Bernoulli’s principle

The pressure exerted on a fluid in an enclosed When the speed of the moving fluid increases,
container can be uniformly transmitted to each the pressure within the fluid decreases and
vice versa.
part of fluid.
Application
Application
Wings of aeroplane
Hydraulic system

SPM Practice 8

Objective Questions

1. Which statements about A Has colour A Pressure acts in all Chapter
hydraulic system is B Not easily evaporated direction
correct? C High adhesion force 8
A Pressure in fluids does D High density B Fluid pressure is only
not depend on the 3. Figure 1 shows spills of water transmitted downwards
depth when the piston is pressed.
B Pressure decreases C Water is a fluid
when the velocity of Figure 1 D When pressure is applied,
fluid increases Which of the following
C Upthrust force the volume of water
increases when the statements is true about the decreases
submerged part rises condition shown in the figure
D Pressure applied to above? 4. Which of the following
fluids is transmitted at statements is correct about
the same value to all the Pascal’s principle?
direction A Gas also adheres to
pascal’s principle
2. Which of the following is B Liquid can be compressed
the property of fluid used in C Liquid need to be
hydraulic system? compressed in an open
system
D Liquid need to be
compressed under freeze
point

175

  Science Form 5 Chapter 8  Force and Pressure

5. Figure 2 shows a hydraulic 9. Figure 4 shows the water 12. Figure 6 shows the changes
system. level in tube S, T and U in the position of a piece of
when water flows through a
Load uniform tube. paper when blown.
(200,000 N)
Force
(10 N)

Surface Surface STU
area area X XY
(0.002 m2)

Water

Figure 2 Figure 4 Figure 6

Calculate the surface area of Which statements is correct Why this situation happens?
X. about the figure above? A The pressure at the
A 1 m2 A Water in tube U is heavier. bottom of the paper
B 40 m2 B The liquid pressure exceeds the pressure
C 2000 m2 increases from X to Y. above it
D 200 000 m2 C The water flows the B The flow of air at the
fastest in Y. bottom of the paper is
6. Which of the following D The temperature of water faster compared to the
devices uses the Pascal’s in X is higher than the upper part
principle for fluid pressure? temperature of water in Y. C The pressure at the upper
A Elevator in a building part and bottom part of
B A vacuum cleaner 10. Figure 5 shows the spinning the paper is the same
C Car brake of table tennis ball when D The blowing of air pulls
D Escalator being hit. the paper straight

7. According to Bernoulli’s Spinning 13. Figure 6 shows a part of
principle, the pressure in fluid of ball aeroplane wings in aerofoil
decreases when fluid shape. The aeroplane is
A does not flow Hitting flying in high speed.
B is added with salt
C flows faster Figure 5 X
D is heated
Which of the following is the Aerofoil
8. Figure 3 shows the flow of path travelled by the ball?
water in Venturi tube. A Y

A Figure 6

PQR A Which statements is correct?
Figure 3 BBA A Pressure in X is larger
than in Y.
Chapter Water Water A B B Pressure in X and Y is
flows out flows in B CB the same.
CDCC C The speed of air in X is
higher than the speed of
C D air in Y.
DD D The speed of air in X is
the same as in Y.
8 Which of the following D
shows the ascending order
of the height of water in 11. Which of the following
tubes P, Q and R? tools works based on the
A P, Q, R Bernoulli’s principle?
B P, R, Q A Syphon
C Q, P, R B Bicycle pump
D Q, R, P C Bunsen burner
D Hydraulic pump

176

Science Form 5 Chapter 8  Force and Pressure

Subjective Questions

Section A

1. Figure 1 shows apparatus set-up to investigate the relationship between the force applied to small piston
and the force produced by large piston.

Weight Weight
m1 m2

A Small B Large
piston piston

Small Water Large
syringe syringe

Rubber tube

Figure 1

(a) State one observation for the experiment. [1 mark]

(b) State the relation between the weight, m1 and the weight m2­.. [1 mark]
(c) State one hypothesis about the force in the experiment. [1 mark]

(d) If small piston A is changed to a piston with similar size as piston B, predict the changes that will occur
at piston B. [1 mark]

(e) Give one example of daily use that applies the work principle as the figure above. [1 mark]

2. Figure 2(a) shows the arrangement of two ping pong balls with a straw is placed in between the balls.
Figure 2(b) shows the straw between the two balls is being blown.

Ping pong balls

Straw     Straw

(a) (b) Chapter
Figure 2

(a) On Figure 2(b), draw both balls to show their positions when the straw is blown. [1 mark]

(b) On Figure 2(b), label 8
(i) the position with low pressure using letter ’L’. [1 mark]
(ii) the position with high pressure using letter ‘H ’. [1 mark]

(c) Why is low pressure produced at L? [1 mark]

(d) Name the science principle related with the changes. [1 mark]

177

  Science Form 5 Chapter 8  Force and Pressure

Section B
3. Figure 3 shows the air flow through the surface of wings of an aeroplane.

Figure 3

(a) Name the shape of wings of the aeroplane. [1 mark]

(b) On Figure 3, mark region with the lowest pressure using letter ‘L’. [1 mark]

(c) Explain how the lift force on the wings can be produced. [3 marks]

(d) Give one example of negative impact from the principle explained in 3(b). [1 mark]

4. Figure 4.1 shows a hydraulic jack is lifting up a car.

Input force Large piston
Small piston

Figure 4.1

(a) Based on Figure 4.1, name the applied principle. [1 mark]
(b) Explain how the car can be lifted up by the hydraulic jack. [2 marks]

(c) Figure 4.2 shows a hydraulic jack produced by a factory. The engineer is requested to modify it in order
to store it in small cars for emergency purposes.

Chapter Figure 4.2

8 Give your suggestions to the engineer. [3 marks]

178

1Chapter Microorganisms Q4 • Production of antibiotics using (ii) A more concentrated
bacteria and fungi. Penicillin is penicillin affects the growth
Checkpoint 1.1 an antibiotic produced by fungi of bacteria more
while streptomycin is an antibiotic
Q1 Algae, bacteria, fungi, protozoa and produced by bacteria. (b) (i) pH, temperature
virus (ii) Concentration of antibiotic
• Dead or weakened microorganisms
Q2 (a) • Consist of genetic material such as bacteria can be used to (c) No clear zone
and protein coat only produce vaccines. A vaccine is 3. (a) To kill or inhibit the growth
given to an individual to stimulate
• Reproduce using the the body to produce antibodies to of microorganisms especially
materials of the living host fight against diseases. bacteria and fungi
cell.
Checkpoint 1.3 (b) Vaccine
(b) • Have chloroplasts
• Have cell walls made of Q1 Aseptic techniques involves taking (c) • Processing food such as
actions and following procedures vinegar in the food industry
cellulose designed to create a condition
free from contamination by • Curing of hide to produce
Q3 According to their shapes such as microorganisms. leather in the leather industry
coccus for spherical bacteria, vibrio
for comma-shaped bacteria, bacillus Q2 • Sterilisation using heat, such as (d) • Cause diseases
for rod-shaped bacteria and spirillum boiling or heating a material or an
for spiral bacteria object • Spoil food
4. (a) How does temperature affects
Q4 pH, temperature, nutrients, light, • Sterilisation using chemicals, such
humidity as using antiseptics or disinfectants the growth of mould?
on a material or an object
Q5 (a) The rate of growth of (b) Bread moulds grow and multiply
microorganisms except viruses • Sterilisation using radiation, such faster at room temperature
increases when the amount of as shining gamma rays onto
nutrients increases provided all material or an object (c) (i) To study the effect of
other factors remain constant. temperature on the growth of
Q3 Antibiotics are used to kill or inhibit bread moulds
(b) All microorganisms except the growth of bacteria.
photosynthetic microorganisms (ii) Variables:
such as algae and some protozoa SPM Practice 1 Manipulated variable:
grow well in dark places.
Photosynthetic microorganisms Objective Questions Temperature
grow well in the presence of light. Responding variable: Growth
1. A 2. D 3. D 4. A 5. B
Q6 The low pH of acetic acid in vinegar 6. C 7. A 8. B 9. B 10. D of bread moulds
is not conducive for the growth of 11. A Constant variables: Light
microorganisms.
Subjective Questions intensity, pH, type of bread
Q7 • To dry the clothes 1. (a) (iii) Procedure:
• Ultraviolet rays from the Sun will kill • Put a slice of bread in each

microorganisms. plastic bag.
• Put a bag with a slice of
Checkpoint 1.2 Figure Bubbles No bubbles
1.1(a) 3 3 bread inside a shoe box
Q1 • Break down indigested food in the and leave it in there for 5
large intestine 1.1(b) days.
• Put another bag with a
• Produce vitamins B and K which (b) Microorganisms such as yeast slice of bread inside an ice
can be absorbed by the human are active when nutrients are box containing ice for 5
body present. days.
• Observe any changes on
Q2 (a) Secretes cellulase enzymes to (c) (i) Presence of nutrient the bread and record the
break down cellulose in plants (ii) Activity of yeast observations.
into simple sugars
(d) Yeast carries out activities when (iv) Tabulation of data
(b) Secretes enzymes to break down nutrients are present
cellulose in wood into sugars Condition
2. (a) (i) The clear zone around Bread in Temperature of bread
Q3 (a) Yeast the filter paper soaked
(b) Bacteria in penicillin of high after 5 days
(c) Bacteria concentration is the biggest.
Shoe box

Ice box

203

  Science Form 5 Answers

2Chapter Nutrition and Food Checkpoint 2.5 Subjective Questions
Technology 1. (a) To study the effect of deficiency
Q1 • Pasteurisation is a process where
Checkpoint 2.1 milk is heated up to 72°C for 15 in nitrogen on the growth of
seconds or 63°C for 30 minutes plants
Q1 (a) The energy content of a food and quickly cooled and packed. (b) (i) Presence of nitrogen in the
(b) Bomb calorimeter
• This process does not kill all the culture solution
Q2 Protein, carbohydrate, fats, vitamins bacteria but it preserves the flavour (ii) Growth condition of the plant
and minerals of the milk. As a result, pasteurised (iii) Original size of corn seedling
milk can only be kept for a few
Q3 (a) Males are generally more active days. / Volume of culture solution
than females, further more;
males have larger body size than Q2 (c) Yellowing of leaves
females 2. (a) (i) Fat: Q
Additive Purpose Example
(b) Teenagers are still growing, and Reason: Margarine has the
they are generally more active. Preservative To kill Sodium highest fat content

Checkpoint 2.2 microorganisms nitrite (ii) Protein: P
Reason: Milk has the highest
Q1 (a) Nutrients needed by plants in so that food can
fairly large quantities. Examples protein content
are potassium and nitrogen. last longer (iii) Carbohydrate: R
Reason: Rice has the highest
(b) Nutrients needed by plants in Colouring To make the Antocyanin
very small quantities. Examples food more carbohydrate content
are boron and zinc. attractive (b) (i) Carrots

Q2 (a) Yellowing of leaves Bleach To make the Benzoyl (ii) Margarine
(b) Stunted growth food appear peroxide
(c) Dead tissues at tip and edges of white and clean (c) High blood pressure
3. (a) P : Nitrogen-fixing bacteria
leaves Flavouring To imitate MSG
Q : Nitrifying bacteria
Q3 (a) To block the sunlight so that the natural flavours R : Denitrifying bacteria
growth of algae in culture solution
can be prevented Stabiliser To give food a Gelatine (b) Nitrogen is absorbed in the form
firmer texture of ions, for example nitrate ions
(b) To supply oxygen to the root
Antioxidant To stop fats in Vitamin C (c) The decomposition of the
Checkpoint 2.3 food from going proteins in the body tissue of
bad dead animals and plants into
Q1 Nitrogen is the important element for ammonium compounds
the formation of proteins and nucleic Emulsifier To prevent fats Lecithin
acids in living organisms. from separating (d) Bacteria/fungi
from mixture
Q2 (a) To change nitrogen gas in the 4. (a) Which classes of food has the
atmosphere into nitrates Checkpoint 2.6 highest calories?100 90 80 70

(b) To change ammonium Q1 By enacting the Food Act 1983 and (b) Cashew nut has a higher60 50 40 30 20 10
compounds produced from the Food Regulation 1985 to ensure calorific value compared to
decomposition of dead remains the foods that are processed are albumen powder and cooking oil
into nitrates safe, wholesome and fit for human
consumption (c) (i) To determine the calorific
(c) To change nitrates to nitrogen gas value of different food
Q3 (a) Through nitrogen-fixing process Q2 Information on the labels of classes.
processed food should include:
or nitrification process (ii) Manipulated variable: Type
• The name of the food of food samples
(b) Through denitrification process • The ingredients and chemicals
Responding variable:
Q4 When plants and animals die, the used in processing the food Calorific value of food
proteins in their bodies will be • The quantity of each ingredient samples
decomposed to produce ammonium • Expiry date
compounds. • The name and address of the Constant variable: Mass of
water
Q5 Decomposition of dead plants manufacturer
and animals produce ammonium (iii)
compounds. Nitrifying bacteria Q3 Has the halal logo as certified by Shield
changes these ammonium JAKIM
compounds to nitrates. Thermometer
SPM Practice
Checkpoint 2.4 Cotton wool

Q1 • Use of quality breeds Boiling tube
• Use of modern technology
• Optimum use of land and irrigated 2

areas Objective Questions Retort Distilled water
• Research and development 1. B 2. A 3. C 4. D 5. A stand Food sample
• Education and guidance for farmers 6. D 7. C 8. A 9. B 10. B Needle
• Efficient land management 11. C 12. C 13. D 14. A 15. C Plasticine
16. A 17. A 18. C 19. B 20. D
21. A 22. A 23. B 24. C 25. B

26. D

204

SCIENCE SPM CC035941 FOCUS SPM

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