PL AR RSO P3L21 Plant Systems WS_1

Primary 3

Rocket Science OEQ

Name ______________
Tutor
Topic PLANT SYSTEMS (LESSON 21)

______________

PLANT SYSTEMS (LESSON 21)

Primary 3: Rocket Science OEQ

Lesson Outline

• Notes
• Activity 1: Open-ended Questions
• Activity 2: Science in Daily life

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Primary 3: Rocket Science OEQ

Leaves

• A leaf is made up of a leaf blade, leaf veins and sometimes, a leaf

stalk.

• Leaves contain a green pigment called which

traps light energy from the sun.

• Although some plants do not have green leaves, they are still able to

make food since they do have chlorophyll.

Leaf functions

• Leaves play a significant role in , a process of plants

making food.

• Leaves contain a green pigment called found in

chloroplasts.

• For photosynthesis to occur, dioxide and are

needed.

• Chlorophyll traps energy from the sun to enable

photosynthesis to occur.

• The light energy is converted to chemical potential energy in forms of

sugars (such as glucose) and oxygen are produced. Excess sugar

is stored as starch.

• Tiny openings known as stomata allow the exchange of oxygen and

carbon dioxide gases with the surrounding.

• Apart from carbon dioxide and oxygen, water vapour is released into

the atmosphere through stomata through transpiration.

• Leaves with surfaces smeared with vaseline will not allow gaseous

exchange and transpiration.

blade

petiole Lesson
stipules

midrib small stomata
vein netted (tiny openings)
AR Model – Stomata
vein

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Primary 3: Rocket Science OEQ

Stem

• Contains water-carrying tubes that transport and

to all parts of the plant.

• Contains food-carrying tubes that transport to all parts of the

plant.

• For some plants, the stem holds the plant upright so that the leaves will be

higher to receive more to make food.

o Not all plants have a strong upright stem. Some plants have weak

stems.

o In order for these plants with weak stems to get more sunlight to make

food,

- some of them climb or coil around a supporting structure to be taller.

- some of them creep and spread themselves on the ground to

increase the surface area of its leaves exposed to sunlight.

Climber – plant with weak stem coiling around
a supporting structure

Creeper – plant with weak stem creeping and
spreading on the ground

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Primary 3: Rocket Science OEQ

Roots

• To absorb and

for the plant.

• To the plant firmly to the ground.

• Trees usually have roots that are longer, thicker and grow deeper into

the soil. These roots help to anchor the tree firmly to the ground,

allowing the tree to grow taller.

AR Model – Roots tap fibrous
root root
Flower

• Important for reproduction as it is the reproductive structure of the
plant. It will develop into fruit after pollination and fertilisation.
Helps the plant to reproduce.

Fruit flower
• Protects the .

• Important for reproduction as it contains
.which will grow into new plants.

seeds fruit

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Primary 3: Rocket Science OEQ

Activity 1 – Open-ended Questions
1. The diagram below shows a plant.

Z

(a) Which part of the plant is Z? [1]
[1]
(b) Y is found inside Z. Y is protected by Z. [1]
Which part of the plant is Y?

(c) What is the function of Y?

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Primary 3: Rocket Science OEQ

2. Johnny placed two similar plants,A and B, in the garden. He removed many
leaves from plant B as shown in the diagram below.

plantA plant B

He observed the growth of both plants over ten days and plotted two

graphs as shown below.

Height of plant Height of plant

Days Days

plantA plant B

(a) From the graphs, what can you conclude about the relationship between

the growth of plants and the number of leaves that they have? [1]

(b) Explain why the number of leaves affects the growth of the plant. [2]

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3. Bryan conducted an experiment using 2 test tubes, S and T. Then, he
placed a young plant into test tube S. Both test tubes were filled with 1 ml
of oil and 25 ml of water.

young 1 ml 25 ml of
plant of oil water

25 ml of
water

ST [2]

(a) What would happen to the amount of water in both test tubes after a
week?

He then planted two plants, U and V, as shown below.

Plant U Plant V

soil

(b) Which plant, U or V, will be more difficult to pull out from the pot? [2]
Give a reason for your answer.

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Primary 3: Rocket Science OEQ

4. The diagram below shows two identical slopes W and X.

Slope W Slope X

(a) Explain why less soil is washed off Slope X than Slope W when it [2]
rains.

Study the roots of Plant Q and Plant R below.

Plant Q Plant R

A farmer wants to grow some plants on his slope to prevent soil from
being washed off in the rain.

(b) Based on the diagram of the roots, which plant should the farmer grow?

W hy? [2]

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Primary 3: Rocket Science OEQ

Activity 2: Science in Daily Life: Top10 strangest plants on Earth

https://www.youtube.com/watch?v=p3St51F4kE8

Discuss Answer

Before Recall all the plant parts and
the functions.
video
What will flowers turn into after
1.00 pollination and fertilization?
1.12
What are the green pigments in
2.10 leaves that help the plant make
food?
What are the 2 important
functions of roots? How does it
prevent soil erosion?

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