Chapter 2 Cells
Module 2.1
Module review answers
Remembering
1 a microscope: an instrument used to make very small things look bigger
b image: what is seen using the microscope
c specimen: the object being looked at through a microscope
2 a binocular microscope
b electron microscope
c micrometre
3 Eyepiece or ocular lens, objective lens
4 It decreases.
5 a Any two of the following: monocular microscope, binocular microscope, stereo
microscope
b Transmission electron microscope and scanning electron microscope
Understanding
6 a Any three of the following: magnifying glass, monocular microscope,
stereomicroscope, electron microscope, telescope, binoculars
b Magnifying glass, monocular microscope, stereomicroscope, and electron microscope
are used when too small. Telescope and binoculars are used when too far away.
7 A magnifying glass makes small clues such as hairs, fingerprints, scratches and
fragments of fabric, easier to see with the naked eye.
8 a The image appears to move to the right.
b The image appears to move to the left.
c The image appears to move upwards.
9 Light from the mirror or lamp has to be able to pass through it. There is very little room
between the stage and objective lens.
10 Electron microscopes use beams of tiny particles called electrons to produce images.
This allows them to have magnifications up to 1 million times, which is much more than
any light microscope can magnify.
Applying
11 a Multiply the magnification of the ocular lens by the magnification of the objective lens.
b See the following table.
Ocular lens
Objective lens
Total magnification
×4
×10
x 40
×10
×100
x 1000
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×4
×40
x 160
12 a Field of view
b It will double in size.
c Student drawings will differ. The dimensions of the cell should be twice those in the
original diagram. See the following figure.
Analysing
13 Cheek cell—about 50 µm in diameter
Fat cell—about 30 µm
White blood cell—about 15 µm
Red blood cell—about 10 µm
14 In a TEM the electrons pass through the specimen. In a SEM the electrons reflect off the
surface of the specimen.
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15 The specimen is usually cut into very thin slices and mounted on a glass slide for the
monocular microscope. There is no preparation necessary for the stereo microscope.
16 Both images will appear in three dimensions showing the surface of the specimen. The
magnification using the SEM will be much greater than the magnification using the stereo
microscope. The image will always be black and white with an SEM.
17 Information that is visible using higher magnification includes: hairs on the legs and
antennae, the many lenses of the eyes, attachment of the antennae and parts of the
mouth, and the surface structure of the head and parts of the mouth. The image from the
SEM does not show true colour.
Evaluating
18 a Scanning electron microscope
b The specimen is not a thin slice, so tiny details of the surface but not the inside of the
specimen can be seen. There is no colour.
Creating
19 See the following table.
Part
Function
ocular lens or eyepiece
the lens you look through; together with the
objective lens magnifies the image
objective lens
together with the ocular lens magnifies the image
coarse focusing knob
brings the stage and objective lens close together
to focus the image when using low power
fine focus knob
sharpens the focus when using high power
mirror or light
directs light up through the specimen
body
holds the lenses in the correct position
stage
the slide or specimen is placed on the stage
stage clips
hold the slide in position
Module 2.2
Module review answers
Remembering
1 a cell: the building block of all living organisms
b cell membrane: the structure (‘skin’) that holds the cell together and controls what
enters and leaves the cell
c mitosis: cell division that produces two identical cells
2 a cytoplasm
b mitochondria
c ribosome
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3 Zacharias Janssen
4 a
b
c
d
Robert Hooke
Antonie van Leeuwenhoek
Robert Brown
Karl Nägeli
5 • All living things are made up of one or more cells.
• Cells are the basic building blocks of all living things.
• New cells are produced from existing cells.
6 The prefix uni means one.
7 Nucleus and cytoplasm
Understanding
8 Cells are too small to be seen with the naked eye.
9 The magnification provides the reader with an idea of the actual size of the objects
represented in the drawing.
10 a and b
A cell membrane: controls the movement of materials into and out of the cell
B nucleus: controls all the chemical reactions within the cell
C cytoplasm: a watery jelly-like liquid that contains all of the cell’s organelles inside the
cell
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11 a and b
A cell wall: provides rigidity and structural support to the plant cells
B vacuole: stores water, wastes and nutrients
C chloroplast: site of photosynthesis
12 a All the contents of the cell would leak out and the cell would die.
b The cell would lack a genetic control centre. The cell would only survive short term.
c Plants would not be able to manufacture the substances they need to survive and
grow.
13 a Diatoms, rotifers, Giardia lamblia
b The water may contain microscopic organisms that could make you sick.
14 The student’s diagram should include one cell divided by mitosis into two cells, then the
two cells both divided and then so on until there were billions of cells.
15 Advantages:
• The cell wall provides structural support and rigidity, which provides great protection
from external injuries.
• It provides mechanical support and determines the shape of the cell.
Disadvantages:
• They make cells more rigid, and therefore less flexible. With a stiff cellular shape, the
cells would not be able to move freely, squeeze and pass through tissues and blood
vessels.
Applying
16 a Mitochondria—mitochondria are the powerhouse of the cell and help release energy
from food
b Ribosomes—the sites of protein production
c Chloroplasts—contain the green pigment chlorophyll that is needed for photosynthesis
to take place
Analysing
17 a Fungal cell
b Mitochondria
18 a Both plant and animal cells have a cell membrane, cytoplasm, a nucleus, ribosomes,
endoplasmic reticulum, mitochondria and vacuoles. Plant cells usually have a single
large vacuole whereas animal cells have many small vacuoles. Only plant cells have
a cell wall and chloroplasts.
b Both plant and fungal cells have a cell membrane, cells wall, cytoplasm, a nucleus,
ribosomes, endoplasmic reticulum, mitochondria and vacuoles. Fungal cells do not
contain chloroplasts.
Evaluating
19 Animal cells do not have rigid cell walls, so a mass of animal cells would collapse in a
heap without a skeleton. Most land animals are mobile and the cells need to be attached
to a rigid structure to be able to bring about movement.
20 The student’s Venn diagram should show the following:
• plant cell: chloroplasts, cell wall and large vacuole
• animal cell: small vacuoles
• both types of cells: cell membrane, nucleus, cytoplasm, endoplasmic reticulum,
ribosomes and mitochondria.
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21 a Plant cell
b There is a distinct cell wall and chloroplasts.
22 a Animal cell
b There is no cell wall visible. Fungal and plant cells have cell walls, whereas animal
cells do not. No chloroplasts are visible.
23 The specimen would have been collected and displayed correctly. You could be certain
that the specimen showed that the cells that were meant to be seen.
24 The student should have moved the specimens into the centre of the field of view before
changing to high power.
Creating
25 Student responses will vary.
Module 2.3
Module review answers
Remembering
1 a axon: long fibre that extends from nerve cells and carries messages over long
distances
b chlorophyll: the green chemical in chloroplasts that traps the Sun’s energy for
photosynthesis
c multicellular: living things made of many cells
2 a specialised cells
b red blood cells
c stomata
3 a Any three of the following: guard cells, photosynthetic cells, conducting cells, structural
cells, root hairs
b Any three of the following: voluntary muscle, involuntary muscle, nerve cells, red blood
cells, white blood cells, white fat cells, brown fat cells
4 Animals have more different types of cells than plants.
5 a
b
c
d
Photosynthetic cells
Nerve cells
White blood cells
Guard cells
6 a
b
c
d
fat cells = where the body stores energy
cardiac muscle = muscle that does not get tired and keeps the heart pumping
red blood cells = carry oxygen from the lungs to the cells
skeletal muscle = cells that contract, causing bones to move
Understanding
7 a A specialised cell is any cell that has a special function (job) to do in the body, for
which the cell has specific structures that enable it to carry out those functions.
b Examples include muscle cells, blood cells and skin cells in animals, and guard cells,
photosynthetic cells and conducting cells in plants.
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8 Specialised cells inside the stem carry water up to the leaves. These cells are long, thin
and hollow.
9 You will be able to see the coloured water move up one side of the celery stick and clear
water move up the other.
10 An example of a suitable tabulated answer is shown in the following table.
Specialised cells
What they do
How they are specialised
photosynthetic cells
make food for the plant
contain a large number of
chloroplasts containing
chlorophyll
conducting cells
carry water and food through the are long and thin like
plant
drinking straws
structural cells
act as the skeleton of the plant
have thickened cell walls
root hairs
take water into the plant
have a large surface area in
contact with the soil
Applying
11 a 5 million multiplied by 450 = 2.25 × 109, or 2 250 000 000
b 6 litres = 6000 mL, so 5 million multiplied by 6000 = 30 × 109, or 30 000 000 000
12 a The most obvious are the guard cells on stomata. Two cells form a pore or opening
into the leaf which allows gasses in and out of the leaves. Clear epidermal cells with a
central nucleus are the most numerous.
b A specialised cell is suited to a particular job. Guard cells open and close the pore in
stomata to allow gases needed by the plant to enter and leave the leaf. They close to
prevent water loss. Epidermal cells create the surface of the leaf and are clear to allow
sunlight to pass through to the photosynthetic cells.
Analysing
13 a Skeletal (voluntary), smooth muscle (involuntary) and cardiac
b Skeletal muscles are attached to bones and have a striped appearance. They help
people move. Smooth muscle is involuntary muscle and is found in the digestive tract.
It does not have a striped appearance. Cardiac muscle is only found in the heart. It is
involuntary muscle and has a striped appearance. Cardiac muscle contracts
throughout the life of a person.
c i Voluntary
ii Voluntary
iii Involuntary
iv Involuntary
Evaluating
14 There would not be organisation into tissues, organs and organs systems. You would not
have sense organs, such as eyes or ears, and you would not have a brain or digestive
system. Your body would have little shape (more like a blob of jelly) and it would be a lot
smaller due to the lack of a circulatory system.
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15 a Student responses will vary. Any cells requiring a lot of energy could be included. The
photosynthetic cells and guard cells are the most obvious suggestions.
b There would be a lot of activity requiring energy in the cells that are photosynthesising.
Also it could be reasonable to think that guard cells require energy to open and close
the stomata.
16 a The smallest plant cells are about the same size as the smallest animal cells.
However, plant cells can be up to four times larger than animal cells.
b i Because plant cells can be bigger than animals cells, they would have been more
easily seen with the earliest microscopes, which were not very powerful.
ii Bacterial cells are about a tenth of the size of the smallest animal cells. They can
only be seen using the most powerful light microscopes. These were not available
to early scientists.
c Because bacteria do not form multicellular organisms, their size remained too small to
be seen by the naked eye and had to wait until powerful microscopes were developed
to be discovered.
Creating
17 a Water is required for photosynthesis and other chemical reactions. It is the main part
of the cytoplasm and helps give shape to the plant.
b The student’s diagram should include the following movement of water, with labels:
i enters plants via the root hairs and leaves through the stomata
ii travels via conducting cells which are long, narrow and hollow
iii shows photosynthesis occurring in the leaves and using water as a raw material.
18 a Student diagrams will vary but all should show long projections from the cell surface.
b The large surface area suggests that the function would be absorption or exchange of
materials. The cell would be from an animal because there is a membrane but no
cell wall.
Module 2.4
odule review answers
Remembering
1 a epithelial tissue: tissue that covers other tissues and organs
b epidermis: epithelial tissue forming the outermost layer of the skin
c tissue: groups of cells that perform the same function in the body
2 a organ
b organ system
3 Cell, tissue, organ, system
4 Any two of the following: epithelium, connective, muscle, nerve
5 Any four of the following: skin, kidney, heart, liver, small intestine, large intestine,
pancreas, bladder
6 Any three of the following: digestive, respiratory, excretory, nervous, skeletal,
reproductive
7 a Leaf
b Root
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Understanding
8 Skin is composed by many different tissues, such as the epidermis, dermis and
hypodermis.
9 Root hairs increase the surface area through which water can be taken in.
10 The task done by specialised cells is often too big for a single cell. For example, an
individual muscle cell is capable of contracting but is not strong enough to bring about
movement in a large organism. It needs to work with other muscle cells
Applying
11 Student diagrams will vary but they all should be consistent with the definitions on page
78. Labelling could include cells, same cells, different cells, tissue and types of cell, parts
of cells, and names of tissues and organs. See the following figure.
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12 Student diagrams will vary but should be similar to the following.
Analysing
13 a A tissue is composed of many cells of the same type. A cell is a small individual unit
that makes up a tissue.
b Organs are made up of a number of tissues. Organs complete part of a task. Systems
are made up of a number of organs. Systems complete all of a task.
14 Both muscles consist of striated muscle.
Cardiac muscle is involuntary muscle, so you do not have to think about making your
heart beat. The muscle is supplied with energy continuously and does not tire, so it is
able to beat continuously without rest.
Skeletal muscle is voluntary muscle, so you have to think about making the muscles
move. The muscles have a good supply of energy but they can become fatigued and
then do not work as efficiently.
Evaluating
15 a Photosynthesis would be reduced (carbon dioxide would not be available).
b Photosynthesis would be halved.
16 a C
b D
c B
17 a Photosynthesis is the process plants use to make glucose. Water from the soil and
carbon dioxide from the air are made into glucose using energy from the sun.
Chlorophyll is needed for this process and oxygen is produced as a waste product.
b Photosynthesis provides plants with the energy they need in the form glucose. Without
photosynthesis there would be no plants. All animals rely on plants directly or indirectly
for food. Without plants there would be no animals. All life depends on photosynthesis.
18 a They would become soft and fragile because the calcium is what makes them strong
and hard.
b You might have problems with your limbs and spine because the bones would break
easily, leading to fractures and injuries.
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Creating
19 Student diagrams will vary but they all should combine the details shown in Figures 2.4.4
and 2.4.5 on pages 78 and 79.
Chapter review answers
Remembering
1 a Cell membrane, cytoplasm, nucleus, and possibly vacuole
b Cell wall, cell membrane, cytoplasm, nucleus, vacuole and chloroplasts
2 a Ocular lens or eyepiece
b Objective lens
3 Photosynthesis
4 Scanning Electron Microscope and Transmission Electron Microscope
5 Changing from low power to high power reduces the field of view.
6 A
B
C
D
E
True
False. When cells of the same type are grouped together, they form a tissue.
False. There are many different tissues in an organ.
True
True
Understanding
7 a plant cell wall: gives structural support to the plant
b cell membrane: controls the movement (passage) of substances entering and leaving
the cell
c nucleus: controls the functioning of the cell
8 The specimen is what you are looking at. The image is what you see through the lenses
of the microscope.
9 The ×10 objective lens is a higher magnification than a ×4 objective lens, so the field of
view will increase.
10 You could lower the objective lens until it touches the slide. This could scratch the lens or
break the slide. You might not lower it far enough to be able to focus on the specimen.
11 a The root hair cells take water from the soil into the plant.
b The shape gives the cell a large surface area through which water can pass.
Applying
12 Figures 2.2.5, 2.2.7, 2.2.9 and 2.2.10 demonstrate the differences. Student diagrams will
vary but they all should show the following:
• the small vacuole in animal cells and the large vacuole in plant cells; an intermediate
vacuole in fungal cells
• chloroplasts in plant cells
• both cell wall and cell membrane in plant cells and fungal cells, cell membrane only in
animal cells.
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13 See the following table.
Ocular lens
Objective lens
Total magnification
x4
x10
x40
x10
x10
x100
x4
x100
x400
x10
X40
x400
x10
x100
x1000
14 See the following table.
Magnification
x10
x100
x1000
diameter field of
view (mm)
3 mm
0.3 mm
0.003 mm
diameter field of
view (µm)
3000 µm
300 µm
3 µm
15 a
b
c
d
Nerve cell
Guard cells
Epithelial cells
Red blood cells
Analysing
16 a
b
c
d
e
Plant
Animal
Animal
Plant
Plant
17 Hooke was looking at the dead remains of cells from a multicellular organism. Only the
cell walls remained. Leeuwenhoek observed living single-celled organisms from pond
water.
18 a Leeuwenhoek microscopes achieved magnifications of up to ×250. .Modern electron
microscopes can magnify things by up to a million times.
b Leeuwenhoek’s microscopes were able to view living cells and in natural colour.
Although electron microscopes can magnify things many thousands of times more
than Leeuwenhoek’s microscopes, they cannot be used to view living cells and only
produce images in black and white.
19 a Multicellular
b Unicellular
c Multicellular
Evaluating
20 The interconnectedness of the fibres means that all parts of the heart muscle can work
together in a coordinated way.
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21 A cube would have a much smaller surface area when compared to a thin, flat shape.
The smaller surface area would reduce the number of stomata and therefore the amount
of carbon dioxide that could be taken in for photosynthesis. It would also reduce the
surface through which energy from sunlight could be trapped. Less carbon dioxide and
energy would reduce the capability of the leaf to carry out photosynthesis.
22 a Student answers will vary.
b Student answers will vary.
Creating
23 See the following figure.
24 Students answers will vary.
Inquiry skills
Research
Answers are students’ own.
Thinking scientifically
1 B
2 A
3 B
4 D
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