iii

Power Tips to Maximise

Your Score in MCQs

Are you facing the same problem as Tina? The fact is, you are not alone. Many

students encounter the same problem too, mainly due to carelessness or an inability

to apply facts they know. Of course, having a misconception that multiple-choice

questions (MCQs) are as easy as ABC makes things worse.

A fact that you must remember ...

In the PSLE Science examination paper, Booklet A consists of 30 MCQs (each carries

2 marks), which accounts for 60% of your PSLE Science score. This means that if you

want to score an A or A* in your PSLE paper, you cannot afford to make more than

three mistakes in Booklet A! In other words, you have to answer 90% of the MCQs

correctly!

Mum, I’ve really done my best. I just don’t understand why I always answer the easiest question wrongly.

Tina, you keep telling me that you’re able to remember your facts and concepts well, yet you always obtain less than 50 marks in Booklet Aof your Science examination paper. Why is that so?

13

Sy

ste

ms

1. The diagram below shows an animal cell.

X

The function of X is to _____________________.

(1) contain the genetic information of the organism

(2) allow substances to pass through the cell

(3) synthesise food for the cell

(4) contain substances that keep the cell Þ rm

( )

2. Four students observed the same cells using a

microscope. Each pupil recorded the parts of the cell

that they could identify. The table below shows their

observations.

Student Observations

Jocelyn Cell membrane, nucleus, cell wall

Richmond Nucleus, chloroplast, cytoplasm

Kelly Cell membrane, cytoplasm, nucleus

Freddy Cell wall, cell membrane, cytoplasm

Which student would not be able to tell that it is a

plant cell?

(1) Jocelyn

(2) Richmond

(3) Kelly

(4) Freddy ( )

Revision Paper 3» Cell System

Name :

Class : Date :30

For each question, there are four options 1, 2, 3 and 4. Choose the correct option and write the number in the brackets provided. Each question carries 2 marks.

Remember this?

Cellmembrane Vacuole

Cytoplasm

NucleusChromosome(contains DNA)

Nucleus

Vacuole

Cellmembrane

Cytoplasm

Cell wall

Chloroplast

Animal cell

Plant cell

24

14. The diagram below shows a circuit tester and a circuit card consisting of four steel

thumbtacks, A, B, C and D. Some of the thumbtacks are connected by wires.

Circuit tester Circuit card with thumbtacks

A

B

C

D

The free ends of the circuit tester were connected to two different thumbtacks at

a time. The observations were recorded in the table below.

Thumbtacks connected Does bulb light up?

A and B Yes

B and D No

C and D Yes

A and D No

Which of the following could be the wire connection on the circuit card?

(1)

D

C

B

A (2)

D

C

B

A

(3)

D

C

B

A (4)

D

C

B

A

( )

**15. The electrical circuit shown below contains four light bulbs, four switches and four

dry cells.

What is the minimum number of switches that has to be closed in order for all the

light bulbs to be lit?

(1) 1

(2) 2

(3) 3

(4) 4 ( )

31

Cycles

*14. The temperature changes in a kettle of water was recorded for 14 minutes and

represented in the graph below.

25

100

A

0 2 4 6 8 10 12 14

B

C D

E

Time/mins

Temperature/ûC

Which of the following statements is/are true?

A. The water in the kettle was initially in the liquid state.

B. There was lesser water in the kettle at Point E than at Point A.

C. The water took 6 minutes to reach its boiling point after it was heated.

D. The kettle of water was heated for 14 minutes.

(1) A and B only

(2) A and C only

(3) A, B and C only

(4) A, C and D only ( )

**15. Four handkerchiefs, P, Q, R and S, of the same size were soaked respectively in different

liquids, A, B, C and D. The volatility of a liquid refers to the ability of the liquid to

evaporate. The diagram below shows the information on the volatility of the four

liquids.

D C B A

Most volatile Least volatile

Using the information provided, which handkerchief will be the lightest after 5 minutes?

(1) P

(2) Q

(3) R

(4) S ( )

91

All T

he

me

s

1. Round faceStraight hairSharp nose

Oval-shaped faceCurved lipsFlat nose

Oval-shaped face

Curved lipsFlat nose

Straight hair Large mouthSquare face

Flat noseRound face

Straight hair

Curly hairSharp noseSquare face

Alice John Jane Calvin

Based only on the above family tree, who looks most like his/her mother?

(1) Alice

(2) John

(3) Jane

(4) Calvin ( )

2. An amoeba is cut into four parts as shown in the diagram below.

A B C D

Which part may survive and grow?

(1) A

(2) B

(3) C

(4) D ( )

Final Revision Paper 2» All Topics

Name :

Class : Date :30

For each question, there are four options 1, 2, 3 and 4. Choose the correct option and write the number in the brackets provided. Each question carries 2 marks.

95

All

Th

em

es

*11. Study the diagram below carefully.

Plant with variegated leaves

When one of the leaves is tested with iodine solution, only the green parts of the

leaf turned dark blue. Which of the following is the appropriate inference that can

be made from the observation?

(1) The leaves of the plant carry out photosynthesis.

(2) Only the green parts of the leaf contain glucose to react with the iodine solution.

(3) Only the green parts of the leaf contain starch.

(4) Only the non-green parts of the leaf contain chlorophyll. ( )

12. Which of the following forces are present in the activity shown below?

A. Elastic spring force

B. Gravitational force

C. Magnetic force

D. Frictional force

(1) A and B only

(2) A and D only

(3) A, B and C only

(4) A, B and D only ( )

*13. The diagram below shows four different circuits, P, Q, R and S.

P Q

R S

In which pair of circuits will the bulbs be of the same brightness?

(1) P and Q

(2) P and R

(3) Q and R

(4) R and S ( )

97

Answer Key

Systems

Revision Paper 1 Revision Paper 2 Revision Paper 3 Revision Paper 4

*

*

1. 32. 13. 24. 45. 26. 17. 48. 2

*

*

9. 310. 311. 212. 413. 314. 115. 3

*

1. 22. 33. 24. 45. 16. 37. 38. 2

** *

* *

9. 110. 311. 212. 213. 414. 215. 4

*

1. 12. 33. 24. 25. 46. 27. 28. 3

* *

*

9. 110. 411. 212. 113. 114. 415. 2

*

1. 12. 23. 14. 15. 36. 27. 38. 1

* * *

*

**

9. 310. 411. 312. 413. 314. 215. 3

Explanations to Selected Questions

Revision Paper 1

*6. Breathing is the physical process whereby oxygen is taken in and carbon dioxide is given out via our respiratory system. The oxygen taken in is used in respiration (a chemical process that occurs in all living cells in our body all the time). This process breaks down glucose (from our digested food) and oxygen into energy, carbon dioxide and water.

Therefore, statement (1) is not true.*8. The air that we inhale consists of about 78% of nitrogen, 21% of oxygen and a remaining 1% of carbon dioxide, water vapour

and other gases. The oxygen is then absorbed by the air sacs in our lungs and thus, there is less oxygen in exhaled air than inhaled air. At the same time, a large amount of carbon dioxide produced from respiration enters the air sacs. When we exhale, the carbon dioxide is removed from our lungs and thus, the proportion of carbon dioxide in exhaled air is higher than that in inhaled air. The proportion of nitrogen in our inhaled or exhaled air remains constant as it is not taken in or given out during the exchange of gases.

Therefore, the option that best represents the proportion of gases is (2).*13. In this experiment, the variable that is changed is the presence of leaves. The limewater in both set-ups is meant to test for

the presence of carbon dioxide. Hence, the purpose of the experiment is to Þ nd out if the leaves give out carbon dioxide. Therefore, the best option is (3).*15. Since the aim of this experiment is to Þ nd out whether the amount of water affects the rate at which plants respire, all the

variables except the amount of water need to be kept the same to ensure a fair test. From the options given, only set-ups C and E satisfy the conditions mentioned. Therefore, the answer is (3).

Revision Paper 2

*8. In the lungs, oxygen is absorbed into the blood in the blood capillaries around the air sacs. The oxygen-rich blood or oxygenated blood ß ows from the lungs to the heart which then pumps it to other parts of the body. On the other hand, oxygen-poor blood or deoxygenated blood ß ows from other parts of the body to the heart before it travels to the lungs so that the carbon dioxide can be removed.

Therefore, the best option is (2).**9. Our body temperature rises when we are having fever. As such, the body temperature needs to be controlled to prevent

overheating. To do so, our heart beats faster in order to bring more blood to the capillaries in our skin so that heat can be released to the surrounding air to cool the body down.

A fever is usually triggered by an infection. The body needs more energy to Þ ght against the infection. Hence, the increased heart rate also aims to supply the body with more oxygen so that more energy can be released during respiration. Given this, option (3) is unacceptable as the increased heart rate does not supply energy directly to the body. Since fever does not cause breathing difÞ culties, option (2) is also incorrect.

Therefore, the best option is (1).