PSLE Final Revision - Flashcards (Answer Key)
Created by Miss Clarissa Ng · www.clartutors.com
48 flash cards to test yourself!
Life Science25 cards · 1–25
Plants · Reproduction
1
What happens during pollination?
Pollen grains from the anther are transferred to the stigma.
Plants · Reproduction
2
Name the four ways seeds are dispersed.
Wind — wing-like structure · water — fibrous husk · animals — juicy flesh or hooks · explosive — pod-like structure
Plants · Reproduction
3
What three things does a seed need to germinate?
Water, air and warmth — not soil, and not light.
Plants · Reproduction
4
What provides the seedling with food before it has leaves?
The stored food inside the seed leaf.
Plants · Water & Food
5
What do roots take in, and what carries it up?
Roots take in water and minerals; the water-carrying tubes carry them up to the leaves.
Plants · Water & Food
6
Write the word equation for photosynthesis.
Water + carbon dioxide, with light and chlorophyll, make glucose (stored as starch) + oxygen.
Plants · Water & Food
7
What do food-carrying tubes do?
Carry food to all parts of the plant — the roots, fruits and flowers.
Plants · Water & Food
8
How is water lost from a leaf?
As water vapour, through the stomata.
Life Cycles
9
Which animals have four stages?
Mosquito and butterfly: egg, larva, pupa, adult.
Life Cycles
10
Which animals have three stages?
Cockroach, grasshopper and frog.
Life Cycles
11
How do you spot an insect?
Six legs and three body parts.
Life Cycles
12
What do all living things do?
Grow, reproduce, and need food, water and air.
Cells
13
Name three useful microorganisms.
Bacteria, fungi and yeast — they make bread and yoghurt, and break things down.
Cells
14
How can microorganisms be harmful?
They spoil food and cause disease.
Breathing & Blood
15
Where does gaseous exchange happen?
In the lungs, where oxygen is absorbed into the bloodstream and carbon dioxide is removed.
Breathing & Blood
16
What happens to the heart rate during exercise?
BE PORED — Body needs more Energy → heart Pumps faster → transport more Oxygen and digested food in the blood → greater rate of Respiration → Release more Energy → carbon Dioxide removed faster
Digestion
17
Name the parts of the digestive system in order.
Mouth, gullet, stomach, small intestine, large intestine.
Digestion
18
Where is digested food absorbed?
In the small intestine.
Food Chains
19
What is a producer?
A green plant — the direct energy source for the animals in the chain.
Food Chains
20
What do the arrows in a food chain show?
The flow of energy from one living thing to the next.
Food Chains
21
Population or community?
Population — all the organisms of the same species living and reproducing together at a given place and time. Community — different populations living together in one place, depending on one another for survival
Food Chains
22
What does extra fertiliser do to a pond?
Increase in number of floating plants → blocks more light from reaching the submerged plants → less light trapped → make less food → lower rate of photosynthesis → grow less healthily
Adaptations
23
Structural or behavioural adaptation?
Structural: fur, blubber, camouflage. Behavioural: migration, hibernation.
Adaptations
24
What does deforestation do to the air?
It raises the amount of carbon dioxide, trapping more heat on the Earth’s surface.
Adaptations
25
Why do animals become endangered or extinct?
Pollution and habitat loss.
Physical Science23 cards · 26–48
States of Matter
26
Which changes of state gain heat?
Melting, boiling and evaporation.
States of Matter
27
Which changes of state lose heat?
Condensation and freezing.
States of Matter
28
What happens to temperature during a change of state?
It stays the same until the change is complete.
States of Matter
29
Boiling or evaporation?
Boiling: bubbles form throughout the liquid, at a fixed temperature. Evaporation: from the surface only, at any temperature.
States of Matter
30
What is dew?
Water vapour condensing on a cold surface.
Electricity
31
What does an open switch do?
Forms an open circuit → no current flows → bulb goes out
Electricity
32
How do you make a bulb brighter?
Use more batteries, or fewer bulbs in series.
Electricity
33
Why does a bulb fuse?
Too much current flowing through the bulb → bulb melts and fuses
Heat
34
Why does a double wall with air between slow heat loss?
Air is a poor conductor of heat, so it conducts heat slowly.
Heat
35
What does heating do to a metal?
Heating expands it; cooling contracts it.
Heat
36
How does a hot metal rim fit onto a wheel?
Heating expands the rim, so it slips on; as it cools it contracts and grips.
Magnets
37
Like poles? Unlike poles?
Like poles repel, unlike poles attract. The force acts at a distance, strongest at the poles.
Magnets
38
What do magnets attract?
Iron and steel only.
Magnets
39
What is an electromagnet?
A current in a coil around an iron bar — a magnet that switches off when the current stops.
Light
40
How do you make a shadow bigger?
Move the object or the light closer to the screen.
Light
41
Transparent, translucent or opaque?
Transparent lets almost all light through, translucent some, opaque none.
Springs
42
What does a spring do when it is pulled or squeezed?
It stretches when pulled and pushes back when squeezed, storing elastic potential energy.
Springs
43
How is the stretch related to the force?
The greater the stretch (extension), the greater the elastic spring force.
Materials
44
How do you choose the right material?
By its properties — strength, flexibility, waterproofing and transparency.
Materials
45
How do you find the volume of a floating object?
By displacement — adding a sinker so the floating object is pulled under the water.
Forces & Energy
46
What do gravity and friction do?
Gravity pulls things down; friction opposes movement. Friction is helpful for grip and braking, harmful as wear.
Forces & Energy
47
Energy change in a lamp?
Electrical energy to light energy + heat energy.
Forces & Energy
48
Energy change in a spring, and where does energy go?
Elastic potential energy to kinetic energy — and some energy is lost as heat and sound energy.