Focus SPM KSSM 2021 Tingkatan 5 - Biology

PELANGI BESTSELLER

BIOLOGY SPM

5Form

KSSM

Sudani Sudin (Textbook Writer) D ual L anguage
Rodiah Abd Wahid (Textbook Writer) P rogramme
Noor Haniyatie Ibrahim • Tan Moi Ho
NEW SPM ASSESSMENT

FORMAT 2021

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

BIOLOGY SPM

Sudani Sudin (Textbook Writer) 5Form
Rodiah Abd Wahid (Textbook Writer)
Noor Haniyatie Ibrahim KSSM
Tan Moi Ho

© 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: 978-967-2965-73-2
eISBN: 978-967-2965-88-6 (eBook)

First Published 2021

Lot 8, Jalan P10/10, Kawasan Perusahaan Bangi,
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CONTENTS

1Chapter Organisation of Plant Tissues 1 5Chapter Response in Plants 80
and Growth
2
1.1 Organisation of Plant Tissues 4 5.1 Types of Responses 81
1.2 Meristematic Tissues and Growth 10
1.3 Growth Curves 18 5.2 Phytohormone 83

SPM Practice 1 5.3 Application of Phytohormones 86
in Agriculture

SPM Practice 5 89

2Chapter Leaf Structure and Function 22 6Chapter Sexual Reproduction in 91
Flowering Plants
2.1 Structure of a Leaf 23
2.2 Main Organ for Gaseous Exchange 26 6.1 Structure of a Flower 92
2.3 Main Organ for Transpiration 30
2.4 Main Organ for Photosynthesis 34 6.2 Development of Pollen Grains and 94
2.5 Compensation Point 43 Embryo Sac
SPM Practice 2 46
6.3 Pollination and Fertilisation 96

6.4 Development of Seeds and Fruits 98

6.5 Importance of Seeds for Survival 100

3Chapter Nutrition in Plants SPM Practice 6 102

49

3.1 Main Inorganic Nutrients 50 7Chapter Adaptations of Plants in 105
Different Habitats
3.2 Organ for Water and Mineral Salts
Uptake 54 7.1 Adaptations of Plants 106

3.3 Diversity in Plant Nutrition 56 SPM Practice 7 111

SPM Practice 3 58

4Chapter Transport in Plants 61 8Chapter Biodiversity 114

4.1 Vascular Tissues 62 8.1 Classification System and Naming 115
4.2 Transport of Water and Mineral Salts 65 of Organisms
4.3 Translocation 70
4.4 Phytoremediation 72 8.2 Biodiversity 121
76
SPM Practice 4 8.3 Microorganisms and Viruses 124

SPM Practice 8 130

iii

9Chapter 11.3 Genes and Alleles 192

Ecosystem 133 11.4 Inheritance in Humans 192

SPM Practice 11 203

9.1 Community and Ecosystem 134

9.2 Population Ecology 151 1 2Chapter

SPM Practice 9 158 Variation 205

1 0Chapter 12.1 Types and Factors of Variation 206

Environmental Sustainability 161 12.2 Variation in Humans 210

12.3 Mutation 213

10.1 Threats to the Environment 162 SPM Practice 12 220

10.2 Preservation, Conservation and 171 1 3Chapter
Restoration of Ecosystems

10.3 Practices in Environmental Genetic Technology 223
Sustainability 172

10.4 Green Technology 176 13.1 Genetic Engineering 224

SPM Practice 10 179 13.2 Biotechnology 227

1 1Chapter SPM Practice 13 231

Inheritance 183 SPM MODEL PAPER 234

11.1 Monohybrid Inheritance 184 ANSWERS 245
11.2 Dihybrid Inheritance 190

iv

7Chapter Adaptations of Plants in
Different Habitats

Cacti can survive I have no idea.
in desert without Hurry up! We need
water. What are to find water. If
their secrets? not, we will die.

CHAPTER FOCUS 105

7.1 Adaptations of Plants

  Biology Form 5  Chapter 7  Adaptations of Plants in Different Habitats

7.1 Adaptations of Plants

1. All organisms have to adapt. Adaptations are the means in which organisms adapt to their environments.
2. Animals and plants possess unique structures and shapes to adapt to their environments to ensure the

survival of their species.

Classification of Plants Based on Habitats
1. Plants in different habitats adapt differently.
2. Based on habitats, plants are classified into mesophytes, hydrophytes, halophytes and xerophytes.

Mesophytes Xerophytes

1. Mesophytes are terrestrial plants which are neither 1. The plants are found in very hot habitats with very
adapted to particularly dry nor particularly wet habitats minimum water and low humidity such as
and grow well in habitats with sufficient water supply. deserts.

2. Most plants are mesophytes. 2. Xerophytes need to adapt to obtain sufficient water
3. Mesophytes live in places which sufficient water and to survive.

sunlight. 3. Examples: Cactus and date palm.
4. Examples: Grasses, rubber trees and mangosteen trees.

Chapter
Chapter

7

Halophytes Hydrophytes

1. The plants which live in swamps at estuaries, where 1. The plants live on surfaces or submerged in water.
freshwater meets seawater. These swampy habitats 2. Hydrophytes are also known as aquatic plants.
are rich in salt contents. 3. Hydrophytes must ensure that they do not absorb

2. Halophytes need to adapt to survive in the habitats excessive water.
with high salt concentration and stagnant water. 4. Examples: Water lettuce and Hydrilla sp.

3. Example: Mangrove tree

Figure 7.1 Classification of plants based on habitats

106

Biology Form 5  Chapter 7  Adaptations of Plants in Different Habitats

MEMORY TIPS! Chapter 4. Many stomata on the leaf surface are always
Chapteropen to allow transpiration to take place.
Phyte refers to plant which lives in an area
Meso means middle. 5. Hydrophyte is a non-woody plant. It is made 7
Hydro means water. up of aerenchyma tissues (Figure 7.5), which
Halo means salt. are light tissues with many air spaces. These
Xero means dry. tissues reduce the density of the plant and
assist it to float.
Adaptive Features of Hydrophytes,
Halophytes and Xerophytes 6. Submerged plants such as Hydrilla sp.
1. Adaptation features are special features that (Figure 7.3) possess leaves and stems that
are thin, small and flexible to assist the plant
enable plant to live and grow in specific to float upright in water and also reduce its
habitats. resistance against the flow of water.
2. Adaptations of plants can be seen in the
structure of their leaves, roots and stems. 7. Water, nutrients and dissolved gases in water
are absorbed directly into the leaves. This
Adaptive Features of Hydrophytes justify the lack of xylem in its stems.

1. Hydrophytes are plants that are adapted to 8. Submerged plants do not have stoma or waxy
live in water with low oxygen content. cuticle on their leaves.

2. Floating plants such as water lettuces have 9. Hydrophytes either have very simple roots or
broad, thin and flat leaves which assist the none at all.
aquatic plants to absorb maximum sunlight
and float on the surface or when submerged in 10. Presence of fine or hairy fibrous roots enable
water. water to be absorbed directly into the plant
(Figure 7.4).
3. Chlorophyll are found on the upper surface of
each leaf to maximise absorption of sunlight; 11. These features of the root assist the plant to
and the upper surface is lined with waxy trap air in the water.
cuticle to reduce water loss to the environment
(Figure 7.2). 12. The plant does not depend on its roots for
support because the buoyancy created by
the surrounding water enables it to float and
remain upright in water.

Upper surface of a lotus leaf is green The shape of leaves and flexibility
whereas the lower surface is reddish of stems of Hydrilla sp. reduce its
in colour. resistance to water flow.

Figure 7.2 Figure 7.3

107

  Biology Form 5  Chapter 7  Adaptations of Plants in Different Habitats

Fibrous roots of water lettuce Aerenchyma tissues in stems of
enable it to trap air. aquatic plant enable it to float on
surface of water.
Figure 7.4
Figure 7.5

SPM HighlightsChapter 3. The leaves, roots and reproduction method
Chapter of mangrove tree are adapted to enable the
The figure below shows an aquatic plant. plants to live in swampy environment where
the soil is soft, oxygen content is low and salt
7 concentration is high (Figure 7.6).

What is the adaptive feature that enable the plant to 4. Light intensity in swamps is high.
live in the habitat?
A Has many fine fibrous roots. 5. To reduce exposure of the leaves to the hot
B Has flexible leaves sun, mangrove tree roll their leaves to reduce
C Has non-woody stems the surface areas.
D Has many xylem tissues
6. In addition, the leaves have thick cuticles with
Examiner’s Tips: fine hairs to reflect wind and sunlight. The
The aquatic plant increases its surface areas to trap presence of water-storage tissues makes the
air bubbles. This makes it less dense than water and mangrove leaves succulent.
enables it to float on the surface of water.
Answer: A 7. Embedded stomata in the leaves help to
reduce the rate of transpiration (evaporation
Adaptive Features of Halophytes of water to the environment), which ensure
1. Halophytes are plants that live in soil with that the rate of photosynthesis is high.

high salinity and low oxygen content. 8. Halophytes tolerate high salt content. Their
2. Mangrove tree are halophytes that live in leaves can store salt and drop off when the
stored salt is too high.
swamps of estuaries, where freshwater meets
seawater. 9. The root system has root which spread wide
and have different shapes and sizes to provide
support to the plant growing in soft and
muddy soil as well as to withstand strong
wind.

10. Mangrove trees have breathing roots known
as pneumatophores that grow above the
ground and absorb water directly from the air.

108

Biology Form 5  Chapter 7  Adaptations of Plants in Different Habitats

11. Pores on pneumatophores known as lenticels ensure that the submerged roots in the soil obtain enough
oxygen supply.

Salt glands in leave remove excess salt.
Old leaves can store salt and drop off when

the salt concentration is too high.

Presence of many air pores Each leaf is lined with waxy
(lenticels) on pneumatophores cuticle to preserve water
to absorb oxygen to the roots. content.

Pneumatophores (breathing roots) Water level during high tide
grow vertically upwards from the
Stilt roots provide additional
main roots. support to the mangrove tree.

Widely spread root system Special root membranes Chapter
Chapter
provides support to the prevent salt from

mangrove tree. entering roots.

Figure 7.6 Adaptations of mangrove tree 7

Adaptive Features of Xerophytes 3. Cuticle is a waxy layer which protects the
1. Xerophytes live in environment with little outer surface of plant.

water, such as desert and areas covered with 4. Whereas succulent refers to the thick structures
ice or snow. of leaves or stems which store water.
2. Xerophytes such as cactus and succulent
plants (Figure 7.8) are capable of overcoming 5. Cactus has few leaves. If leaves are presence,
extreme drought. they are small and covered with thick cuticle.

Figure 7.7 Succulent plant 6. Most photosynthesis occurs in stems of
xerophytic plants.

7. Presence of embedded stomata dan numerous
layers of upper epidermis assist in reducing
evaporation of water from the leaves and
stems.

8. Opening of stomata at night enables collection
of carbon dioxide during night-time for
photosynthesis in the daytime.

9. Thorns that have been modified from leaves
reduce the total surface areas exposed to
the sun, hence reduce loss of water to the
environment.

109

  Biology Form 5  Chapter 7  Adaptations of Plants in Different Habitats

10. Thorns protect the plant from animals which 14. Succulent plants have succulent leaves and
seek water. stems which store water for usage during long
drought.
11. Thorns also provide shade to the surface of
cactus from extreme light intensity of the sun. 15. In the artic, tiny plants such as mosses and
grasses are classified as xerophytes because
12. The cactus roots grow wide and deep into the they cannot absorb water from frozen ground.
ground to absorb water and mineral salts.
16. These plants have tiny leaves to ensure
13. There are cacti which absorb humidity from minimum loss of water to the environment.
fog and dew through their stems and thorns.
The absorbed water is stored in roots, tubers,
stems and leaves.

Waxy layers cover Leaves are modified
succulent leaves to to thorns to reduce
preserve water content in loss of water through

the leaves transpiration

Thorns on stems Ground surface
protect plant from
being eaten by animals

Chapter Below ground surface
Chapter

7

Roots grow wide in the
ground to absorb water

Tubers that can
store water

Roots grow deep into the
ground to absorb water

Figure 7.8 Adaptations of xerophytes

Checkpoint 7.1

1. State the types of plants and their habitats given below:
(a) Aloe vera (Common name: Lidah buaya)
(b) Nelumbo nucifera (Common name: Lotus or teratai)
2. Differentiate between hydrophytes and halophytes.
3. Darwish watered his cacti plants three times a week. He noticed that his cacti grow very fast but after a few

weeks, his cacti became soft and turned yellowish. Discuss the causes of his cacti conditions.

110

cCONCEPT MAP Biology Form 5  Chapter 7  Adaptations of Plants in Different Habitats

ADAPTATIONS OF PLANTS
IN DIFFERENT HABITATS

Mesophyte Uptake of water and
Hydrophyte mineral salts
Halophyte
Xerophyte Gaseous exchange

Support

Photosynthesis

SPM Practice 7 Chapter
Chapter

7

Objective Questions 3. The statements below are
about plant K. Figure 1
1. Which is the main importance
of adaptations in plants? • Grow in desert What is the importance of
A Ensure survival of • Has thorns on its fronds the stem structure?
species A Provide support to the
B Receive sufficient and stems plant
sunlight • Has roots which are B Reduce density of plant
C Protect from being eaten C Increase rate of gaseous
by animals long and penetrate exchange
D Reduce excessive loss deep into ground D Absorb maximum
of water sunlight

2. Which of the following is a Which of the following is an
mesophyte? example of plant K?
A Water spinach A Mango tree
(kangkung) B Mosses
B Lotus plant C Mangrove plant
(pokok teratai) D Date palm
C Cactus plant
(pokok kaktus) 4. Figure 1 show a cross-
D Coconut tree section of a stem of a lotus
(pokok kelapa) that can be found in a
watery habitat.

111

  Biology Form 5  Chapter 7  Adaptations of Plants in Different Habitats

5. Figure 2 shows the condition What is structure X? 9. Which are the adaptations of
of Hydrilla sp. after it is A Thorn thorns in cactus?
removed from water. B Hydathode I To reduce water loss
C Pneumatophore II To provide cooling effect
D Aerenchyma tissues to cactus
III To maximise absorption
7. Which of the following are of sunlight
Figure 2 the adaptive features of a IV To prevent cactus from
Why is the stem of Hydrilla sp. halophytic plant? being eaten by animals
I Succulent leaves A I, II and III
bent when it is not in water? II Leaves have embedded B I, II and IV
A Increased in density stomata C I, III and IV
B Absence of buoyancy III Presence of lenticels on D I, II, III and IV
C Stem became compact breathing roots
D Absence of aerenchyma IV Small leaves with thick 10. What causes a succulent
cuticle plant to die when it is
tissues A I, II and III exposed to soil which is
B I, III and IV always moist?
6. Figure 3 shows a mangrove C II, III and IV A Dropping of leaves
swamp. D I, II, III and IV B Rotting of roots
C Drying of leaves
8. Why does a water lettuce D Shrinking of stems
plant have roots which are
Chapter fine and hairy?
Chapter A To reduce water
resistance
7X B To trap air in water
C To enable it to float in
water
D To increase absorption of
water and minerals

Figure 3

Subjective Questions

Section A

1. Figure 1 shows a tropical rainforest. The forest receives a lot of rain throughout the year. The rainforest is
made of different trees with different heights, which subsequently structured the forest into a few layers.

Figure 1

112

Biology Form 5  Chapter 7  Adaptations of Plants in Different Habitats

(a) (i) Identify the types of plants that live in a tropical rainforest. [1 mark]
(ii) Explain your answer in (a)(i). [1 mark]

(b) What are the adaptations of the leaves of plants that grow on the shady forest floor? Explain.
[2 marks]

(c) In a tropical rainforest, there are also hydrophytes such as lotus plants that grow on the surface of lakes.

(i) How does a lotus plant overcome excessive water in its environment? [2 marks]

(ii) The upper surfaces of leaves of a lotus plant are lined with waxy and thick cuticle. How does this
[2 marks]
feature assist a lotus plant to live in lake?

2. Figure 2 shows pineapple plants. A pineapple plant has succulent leaves which are long, thorny and the
upper surfaces are lined with thick cuticle. These leaves surround a thick succulent stem.

Chapter
Chapter

Figure 2 7

(a) (i) Based on its habitat, which type of plant is a pineapple plant? [1 mark]
(ii) Explain your answer in (a)(i). [1 mark]

(b) Explain the adaptations of pineapple plant that enable it to carry out photosynthesis in an environment
[3 marks]
which lacks water.

(c) Explain why a pineapple plant cannot withstand long period of cold weather. [2 marks]

(d) If you plant a pineapple plant in a pot, justify your choice of location for your pot of pineapple plant.
[2 marks]

113

1Chapter Organisation of Plant Q2 Biennial plants are plants that take two (c) Vascular cambium
Tissues and Growth years with two seasons of growth to Secondary phloem
complete their life cycle.
Checkpoint 1.1 Secondary xylem
Q3 Growth Primary xylem
Q1 Permanent tissues are matured (dry mass)
tissues which have experienced or are
experiencing differentiation. C D E Primary phloem
AB F
Q2 (a) Stores for substances such as Cork cambium forms
starch, sugar and water. Plant dies below the epidermis

(b) Provides support and shape to Time 2. (a) Tissue X: Xylem tissue
herbaceous plants. Tissue Y: Phloem tissue
AB Stage (b) Tissue X: Transports water and
(c) Undergoes photosynthesis
(palisade mesophyll cells and • There is a slight drop in weight during mineral salts from the roots to the
spongy mesophyll cells are the germination process because
parenchyma cells which have some food stored in the dicotyledon leaves.
undergone specialisation) was used for cell respiration. Tissue Y: Transports organic

Q3 • The sieve tubes carry organic BC Stage substances from the leaves to other
materials from the leaves to other
parts of the plant. • Plant undergoes photosynthesis. parts of the plant.

• Companion cells provide energy and • Weight increases because the amount (c) Water cannot be transported
nutrients to sieve tubes. of food produced exceeds the amount from the roots to the leaves.
of the food used.
Checkpoint 1.2 Photosynthesis cannot occur. Food
CD Stage
Q1 Growth refers to the changes that occur cannot be produced. The plant will
in an organism involving the increase in • Growth rate begins to slow down.
the number of cells, volume, size and die.
mass. DE Stage 3. (a) Tissue P: Sclerenchyma tissue
Tissue Q: Parenchyma tissue
Q2 The change in mass consists of two • The rate of food production is Tissue R: Collenchyma tissue
types, wet mass and dry mass. the same as the rate of food (b) • Tissue R is collenchyma tissue
consumption.
(i) Wet mass refers to a measurement which are simple cells unevenly
of mass that does not involve the • Growth rate is zero.
death of the plant sample. However, thickened with pectin and
this measurement is less accurate EF Stage
because of the ever-changing water cellulose.
content in living plants. • The plant’s weight decreases due to
the lower photosynthesis rate. • Provides mechanical support to
(ii) Dry mass refers to the mass that young plants, herbaceous plants
is obtained after all of the water • Point F shows the dry mass of the and non-woody plants.
content in the plant has been plant upon death.
eliminated. Plants must be dried Section B
at a temperature of 100°C until
its mass no longer changes. SPM Practice 1 4. (a) • Growth is an irreversible process
This is suitable for measuring that occurs in organisms involving
plant growth. the increase in the number of
cells, volume, size and mass.
Q3 • Produces new cells for plant growth to
achieve maximum height Objective Questions • In the cell division zone, cells
1. B 2. A 3. A 4. A 5. D divide actively via mitosis.
• Allows the shoots to grow upwards 6. D 7. C 8. D 9. A 10. C
in search of sunlight while roots will • In the cell elongation zone, cells
grow downwards to seek out water lengthen by absorbing water
Subjective Questions forming large vacuoles.
• Produces primary xylem which
transports water and mineral salts Section A • In the differentiation zones, cells
from the roots to the leaves will differentiate into specialised
1. (a) (i) Cells in zone I are smaller, have cells.
• Produces primary phleom which larger nuclei and no vacuoles
transports organic material from the whereas cells in zone II are (b) • Secondary growth in
leaves to other parts of the plant. larger, have small nuclei and dicotyledonous stems occur when
large vacuoles. the vascular cambium cells divide
Checkpoint 1.3 actively via mitosis
(ii) Cells in zone I divide to produce
Q1 Plants can be divided into three types: new cells which are added into • A vascular cambium ring will form.
zone II. Cells in zone II absorb
(a) Annual plants water causing the vacuole to • The vascular cambium cells will
enlarge and the cells to expand form two layers, the secondary
(b) Biennial plants to maximum size. xylem towards the inside and the
secondary phloem towards the
(c) Perennial plants (iii) Shoot apical meristem outside.

(b) • During this process, the primary
Cambium xylem is pushed towards the
pith whereas primary phloem is
Xylem pushed towards the epidermis.
Phloem

245

  Biology Form 5  Answers

• Year after year, secondary EF Stage Checkpoint 2.2
growth will continue and cause
the old xylem tissues in the • The plant’s weight decreases due Q1 Stomata allow the exchange of carbon
middle section of the tree to be to the lower photosynthesis rate. dioxide and oxygen between the air
compressed and turn into wood pockets inside the spongy mesophyll
• Point F shows the dry mass of the cells and the surrounding environment.
• To increase strength and provide plant upon death.
mechanical support, cells in Q2 Stomata close on hot and sunny days
those parts will undergo lignin (b) AB Stage to reduce the loss of water through
thickening. transpiration.
• There is a slight drop in weight
• Cambium cork cells below the during the germination process Q3 During the day, sunlight stimulate
epidermis will divide actively to because some food stored in photosynthesis in guard cells.
form cork cells in the outside the dicotyledon was used for cell Potassium ions from cells next to the
and a secondary cortex on the respiration. guard cells are transported into the
inside. guard cells through active transport.
BC Stage This causes that guard cells to become
• The wall of the cork cells hypertonic.
contains suberin which is a waxy • High growth rate of leaves, stems
substance that is waterproof. and roots. Checkpoint 2.3

• Cork tissues will replace cracking • Plants undergo photosynthesis. Q1 Transpiration is the process of water
or broken epidermis. loss in the form of water vapour from
• Weight increases because the the surface of plants to the environment.
• The cork tissue protects the tree amount of food produced exceeds The importance of transpiration are as
tissues from dessication the amount of the food used. follows:
(over-drying), bacterial infections
and mechanical damage. CD Stage (i) Transpiration causes the movement
of water and mineral salts to other
(c) • Provides mechanical support • During the winter periods, trees parts of the plant.
to dicotyledonous plants by remain dormant, growth will be
increasing the circumference of temporarily suspended. (ii) Transpiration allows absorption and
the roots and stems. movement of water and mineral
• The weight of plants reduces salts inside the vascular tissues
slightly as growth does not occur.
(iii) Transpiration gives a cooling effect
• Produces new xylem and phloem DE Stage to plants. Evaporation of water
tissues to replace dead or from mesophyll cells involves the
damaged tissues. • In spring or summer, the stems absorption of the latent heat of
will grow fast. vaporisation from leaves.
• Produces secondary xylem and
phloems for transportation of • Plants will produce flowers, fruit (iv) Transpiration eliminates excess
water, mineral salts and organic and seeds. water from plants and with that,
materials. helps maintain osmotic pressure in
EF Stage the cell sap
• Produces woody tissues whereby
woody tissues are produced by • The plant’s weight decreases due Q2 When the relative humidity of air is
older xylem tissues in the middle to the lower photosynthesis rate. lower, compared to the atmosphere,
section. then the concentration of water vapour
• Point F shows the dry mass of the in the air spaces between cells is high.
plant upon death. The air is dry causing water vapour to
exit the stomata and evaporate into
• Produces cork tissues which the atmosphere. Transpiration rates
provides protection against increases.
parasites and pests. 2Chapter Leaf Structure and
Function Q3 Water movement scheme until exit to
• Increases the life span of trees for the atmosphere:
survival of the species

5. (a) • The growth curve for maize shows Checkpoint 2.1
a sigmoidal curve (S-shaped).
Q1 The leaf mesophyll layer consists of
• The growth curve of annual palisade mesophyll cells and spongy
plants can only be obtained by mesophyll cells. The differences
measuring its dry mass. between palisade mesophyll cells and
spongy mesophyll cells are as follows:
AB Stage Soil Root Stem Leaf
water xylem xylem xylem
• There is a slight drop in weight
during the germination process Palisade mesophyll Spongy mesophyll
because some food stored in
the dicotyledon was used for cell cells cells
respiration.
Located below the Located below
BC Stage upper epidermis palisade mesophyll Water Air Leaf
cells evaporated spaces mesophyll
• Plant undergoes photosynthesis. between
into the cells
• Weight increases because the atmosphere cells
amount of food produced exceeds Long-shaped, No distinct shape,
the amount of the food used. vertical and tightly loosely packed with
packed plenty of air pockets
CD Stage between the cells Checkpoint 2.4
• Growth rate begins to slow down.
Q1 Leaves are flat, thin, wide and contains
DE Stage Q2 Controls the opening and closing of mesophyll cells which are packed with
stomata. chloroplasts.
• The rate of food production is
the same as the rate of food Q3 The irregular shape of spongy Q2 The difference between light-dependent
consumption. mesophyll cells increases the surface reactions and light-independent
area for gas exchange. reactions.
• Growth rate is zero.

246

BIOLOGY SPM CC035441 FOCUS SPM

5Form

KSSM
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üSPM Practices üSPM Model Paper
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