Download Chapter 2: Cells Unit 2.1 1 An eyepiece or ocular lens and objective

Chapter 2: Cells
Unit 2.1
1
An eyepiece or ocular lens and objective lens
2
Micrometre
3
It decreases.
4 a
b
5
Two from: monocular microscope, binocular microscope, stereo microscope
Transmission electron microscope, scanning electron microscope
Small objects can be magnified (made bigger) so that they are easier to see.
Without a magnifying glass some very small clues could be missed.
6 a
7
Microscope—an instrument used to make very small things look bigger.
b
Specimen—the object being looked at through a microscope.
c
Image—what is seen using a microscope.
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.
8
Light from the mirror or lamp has to be able to pass through it.
9
Multiply the magnification of the eyepiece or ocular lens and the magnification of
the objective lens.
10 The electron microscope is able to magnify many more times, therefore smaller
objects become visible.
11 a
50 mm
b
8 mm
c
1 000 000 000 µm
12 3000 µm
Copyright © Pearson Australia 2011 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 2356 2
Page 1
40
13 a
b
1000
c
160
14 The image created should be twice the length and twice the width of the image
shown in Figure 2.1.5.
15 The approximate diameters of the cells are 50 µm for a cheek cell, 30 µm for a fat
cell,10 µm for a red blood cell and and 15 µm for a white blood cell.
16 In the TEM the electrons pass through the specimen. In the SEM the electrons
reflect off the surface.
17 The specimen is cut into very thin slices for the monocular microscope. There is
no preparation necessary for the stereo microscope.
18 Both these images would be three dimensional. The SEM image would be greatly
magnified compared to the image from a stereo microscope.
19 a
An SEM
19 b
It is a three-dimensional image. Therefore it could be produced by a stereo
microscope or an SEM. However, the magnification is greater than could be
achieved using a stereo microscope and so it must be from an SEM.
20
Part of microscope
Function
Ocular lens or eyepiece
Magnifies the image
Objective 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
Copyright © Pearson Australia 2011 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 2356 2
Page 2
Inquiring
1
Monocular or binocular—up to 1000 times. Stereo microscope—up to 100 times.
SEM—500 000 times. TEM—over 1 000 000 times
2
In 1939 by Ernst Ruska
3
•
Defect analysis and failure analysis of electronic circuits
•
Diagnosis—defects at a cellular level; viral infections; toxicology
•
3D imaging of cell structure
•
Analysis of materials—defects
•
Nanotechnology
•
Forensic science
•
Analysis of minerals
4
A negative particle found in atoms
Unit 2.2
1 a
b
Nucleus
c
Cytoplasm
2 a
Cell membrane
b
Chloroplasts
c
Cell wall
3 a
4
Cell membrane
Cell membrane
b
Nucleus
c
Cytoplasm
a
Cell wall
b
Vacuole
c
Chloroplast
5
Photosynthesis
6
They are too small to be seen with the naked eye.
Copyright © Pearson Australia 2011 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 2356 2
Page 3
7 a
8
All the contents of the cell would leak out and the cell would die.
b
There would be nothing to control what happened in the cell.
c
Plants would not be able to manufacture any food and would die.
The magnification provides the reader with an idea of the size of the objects
represented in the drawing.
9 a
Mitochondria
b
Ribosomes
c
Chloroplasts
10 a
Fungal cell
b
Endoplasmic reticulum
c
Mitochondrion
d
Plant cell
11 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.
12 Fungal cells do not have chloroplasts, whereas plant cells do. Cells of fungi have
a cell wall like a plant cell. However, plant and fungal cell walls are made of
different chemicals.
13 Cell walls provide a skeleton that enables plants to remain rigid. Another
advantage of having cell walls is that they protect the cell membrane, making it
less susceptible to damage.
A disadvantage of having a cell wall is that it makes cells relatively inflexible.
Also, materials moving into or out of a cell must pass through the cell wall as well
as the membrane.
14 Animal cells do not have any independent means of support. They would collapse
in a heap without a skeleton. The cells need to be attached to a rigid structure.
Copyright © Pearson Australia 2011 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 2356 2
Page 4
15 Plant cell—chloroplasts; cell wall
Both—cell membrane; nucleus; cytoplasm; endoplasmic reticulum, ribosomes,
mitochondria; vacuole
Possibly include a large vacuole in the plant cell and many small vacuoles in the
animal cell. The vacuole would then be deleted from ‘both’.
16 a
b
17 a
b
A plant cell.
There is a distinct cell wall and there are chloroplasts.
Animal
There is no cell wall visible. Fungal and plant cells have cell walls, whereas
animal cells do not.
18 If the cells were not collected correctly, injury or infection could occur. Infections
could be passed from one person to another if someone other than the donor
touched the cells on the slide.
19 The specimen would have been collected and displayed correctly.
You could be certain that the specimen included the cells that were intended for
focus.
20 Consisting of a few large cells, we would be more vulnerable to damage.
We would be less flexible.
Our few cells would have to carry out all the functions rather than having cells
specialised for different functions.
It would be more difficult to maintain the shape of the human body, with arms,
legs, fingers and so on.
Inquiring
1
The answer will depend on the information gathered by students.
2
Answers will depend on the scientist chosen and the source that the students
use.
3
The answer will depend on the information gathered by students. The answer
should include links between the development of microscope technology and our
knowledge of cells.
Copyright © Pearson Australia 2011 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 2356 2
Page 5
Unit 2.3
1
Three from: guard cells; photosynthetic cells; conducting cells; structural cells;
and root hairs
2
Three from: voluntary muscles; involuntary muscles; nerve cells; red blood cells;
white blood cells; white fat cells; and brown fat cells
3
Animals
4
a
One
b
Many
5 a
Photosynthetic cells
b
Nerve cells
c
White blood cells
d
Guard cells
6 a
b
Fat cells—where the body stores energy
Cardiac muscle—muscle that does not get tired and keeps the heart
pumping
c
Red blood cells—carry oxygen from the lungs to the cells
d
Skeletal muscle—cells that contract causing bones to move
7 a
Cells that have a special job to do in the body and have a structure that
makes them better able to do their job.
b
There are many different jobs to do in the body and different cells have
specific characteristics that make them better suited to carrying out one or
other of these jobs.
8 a
5 million multiplied by 450 = 2.25  109
= 2 250 000 000
b
6 litres = 6000 mL
5 million multiplied by 6000 = 30  109
= 30 000 000 000
Copyright © Pearson Australia 2011 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 2356 2
Page 6
9 A
Multicellular
B
Unicellular
C
Multicellular
10 Unicellular organisms: made of one cell only; one cell carries out all the functions
of living things; microscopic
Multicellular organisms: made of many cells; specialisation of cells to carry out
different functions; microscopic and macroscopic
11 a
Voluntary
b
Voluntary
c
Involuntary
12 Voluntary muscles only work when the decision has been made to make them
work.
Involuntary muscles work without conscious input. They do not work
continuously.
Cardiac muscle works continuously.
13 a
A leaf cell would contain chloroplasts. It could be long and flat in shape.
A root cell would not contain chloroplasts. It may have a large surface area.
b
Leaf cells carry out photosynthesis, therefore, a long, flat shape would
maximise the surface area exposed to sunlight. The chloroplasts are
necessary so that the plant can trap energy from the Sun.
Root cells are not exposed to light, therefore they would not contain
chloroplasts. Some root cells (root hairs) take in water. These cells have a
large surface area in contact with the soil.
14 All the cells of your body would have to carry out all of the functions of the body.
There would be no organisation into tissues, organs and organ systems. You
would not have sense organs such as eyes or ears; you would not have a brain
or a digestive system. Therefore it is likely that 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.
Copyright © Pearson Australia 2011 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 2356 2
Page 7
15 a
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 would be reasonable to think that guard cells
require energy to open and close the stomata.
16 a–c
Photosynthetic
cells
Conducting
cells
Structural cells
Root hairs
17 a
Make food for the plant
Carry water and food
through the plant
Act as the skeleton of the
plant
Take water into the plant
Contain a large number of
chloroplasts
Are long and thin like drinking
straws
Have thickened cell walls
Have a large surface area in
contact with the soil
The pictures 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. There is a membrane but no cell wall.
Inquiring
1
The stinging cells on jellyfish release poison into any predator or prey that comes
into contact with them. This allows the jellyfish to avoid being eaten by the
predator or to disable and eat its prey.
2
Not having a nucleus means that the red blood cell has space to put even more
of the chemical (haemoglobin) that carries oxygen.
3 a
Fungal cells have cell walls made of protein. This is the same protein that
makes the exoskeleton of insects and spiders. The cells of diatoms are like
plant cells. Each cell is encased in an outer covering made of silica
(hydrated silicon dioxide)—the chemical found in sand. The outer covering is
known as a frustule. Frustules come in a wide variety of shapes, but usually
consist of two asymmetrical sides with a split between them. This
characteristic is the reason for the group’s name—dia, meaning two.
b
Neither plant nor animal cells have an outer covering that could be
compared to a frustule. The cell walls of fungi and of plants have a similar
Copyright © Pearson Australia 2011 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 2356 2
Page 8
function, although they have a different composition. Animal cells do not
have a cell wall.
c
Diatoms are included in the protists. This diverse group includes unicellular
organisms that are difficult to classify and do not fit easily into the other
groups.
Fungi are in a group of their own. Although they have a cell wall like plants,
the cell wall is chemically different. No fungi contain chlorophyll. These two
characteristics make them different enough to be classified into a separate
group.
4
Bacteria assist in the digestive system and without them you would gain less
nourishment from your food and you could lack vitamin K. Bacteria are used to
make cheese and yoghurt. They help to break down wastes in natural
ecosystems and in sewage treatment plants. They are also used to make drugs
and other chemicals, such as insulin, that keep us healthy.
Unit 2.4
1
Cell; tissue; organ; system
2
Mentioned in the text are: skin; kidney; heart; and liver
3
Two from: epithelium; connective; muscle; and nerve
4
Mentioned in the text are: digestive; respiratory; excretory; nervous; and
reproductive systems
5
Mitosis
6
Several organs that work together to complete a task.
7
Skin contains many different types of cells. The cells are organised into tissue
layers that form the skin. Skin is an organ because it is made up of many different
tissues.
8
The idea should come through that cells are very tiny therefore any contraction
could change the position of the arm by only a microscopic amount. Millions of
cells working together amplify the microscopic change into a visible change.
Copyright © Pearson Australia 2011 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 2356 2
Page 9
9
A group of cells of the same type is a tissue. Tissues group together to form
organs.
10 a
A tissue is composed of many cells of the same type. A cell is a small part of
a tissue.
b
Organs are made up of a number of tissues. Organs complete part of a task,
e.g. the small intestine performs the absorption part of digestion.
Systems are made up of a number of organs. Systems complete all aspects
of a task, e.g. the digestive system performs all aspects of digestion.
11 a
Without nerve tissue you would not be able to gather information from the
environment or send messages rapidly throughout the body; and you would
not have a brain to send the messages. You would be unable to function.
b
Without ligaments the bones of your skeleton would not be connected to
each other and would not be able to make coordinated movements.
Without tendons the muscles would not be attached to the bones. Without a
fixed point to pull against, the muscles would therefore not be able to
contract. So the muscles would not be able to move the bones.
12 Students should use information from the text, pictures and the practical activity
on muscle fatigue.
Both muscles are striated.
Copyright © Pearson Australia 2011 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 2356 2
Page 10
Cardiac muscle is involuntary. Therefore you do not have to think about making
the heart beat. The muscle is continuously supplied with energy and does not
tire. Therefore it is able to beat continuously without rest.
Skeletal muscle is voluntary. Therefore you have to think about making the
muscles move. The muscles have a good supply of energy, but they do become
fatigued and when fatigued, do not work as efficiently.
13 a
They would become soft and flexible because the calcium deposits are what
make them strong and hard.
b
Your bones could become weak and you could be more likely to have breaks
or sprains.
14 a
C
b
D
c
B
15 They cannot get enough oxygen or food to make the energy they require. They
do not have enough mitochondria to release energy quickly enough to replace
stores that were there.
16 The diagram should be similar to Figure 2.4.5 from the student book, but should
also include labels showing how the bicep and tricep work together to bend or
straighten the arm. The tendons should also be labelled.
Inquiring
1
The answer will depend on the body system chosen.
2
Sepals protect the developing flower in the bud. In some species the sepals are
brightly coloured and attract insects.
Petals are usually brightly coloured and attract insects for pollination.
Stamens comprise the filament and anther. The filament holds the anther in a
position where the pollen can be collected on the bodies of insects or by the
wind. The anther is where the pollen grains are formed. Pollen contains the male
sex cell.
Pistils comprise the stigma, style and ovary. The stigma collects the pollen, the
style hold the stigma in position so that it can collect the pollen. The ovary
contains the ovules, which in turn contain the female sex cell. When fertilisation
Copyright © Pearson Australia 2011 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 2356 2
Page 11
has occurred, the ovule becomes the seed with the developing embryo, and the
ovary becomes the fruit.
Chapter Review
1
Parts of an animal cell that can be
seen under a light microscope
Cell membrane
Cytoplasm
Nucleus
Possibly vacuoles
2 a
b
Parts of a plant cell that can be seen
under a light microscope
Cell wall
Cell membrane
Cytoplasm
Nucleus
Vacuole
Chloroplasts
Ocular lens or eyepiece
Objective lens
3 Photosynthesis
4
Unicellular organisms are composed of one cell only. Multicellular organisms
have many cells.
5 a
6
Forms the structural skeleton of the plant
b
Controls the movement of things entering and leaving the cell
c
Controls the functioning of the cell
The specimen is what you are looking at. The image is what you see through the
lenses of the microscope.
7
Changing from low power to high power reduces the field of view. Any objects
seen through the microscope will appear bigger.
8
The 10 objective lens is a higher magnification than a 4 objective lens.
Therefore, the field of view will decrease.
9
You could accidentally lower the objective lens until it touches the slide. This
could scratch the lens and/or break the slide.
10 a
b
The root hair takes water into the plant from the soil.
The cell has a very large surface area in contact with the soil, and therefore
a large surface area through which water can pass.
Copyright © Pearson Australia 2011 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 2356 2
Page 12
11 Muscle cells use a large amount of energy. Mitochondria are the organelles that
release energy and make it available to the cells.
12 Line drawings should show the small vacuole in animal cells and the large
vacuole in plant cells. An intermediate vacuole should be shown in fungal cells.
Chloroplasts should be shown in plant cells. Both cell wall and cell membrane
should be shown in plant cells and fungal cell. The cell membrane only should be
shown in animal cells.
13 Possibly a line drawing or photographs from the internet with magnifications to
demonstrate that organelles are much smaller than complete organs
A drawing showing the relationship between organelles and organs—possibly a
body with an enlarged section showing an organ, and then an enlarged section of
the organ showing the cell and the organelle
14
Ocular lens
Objective lens
Total
magnification
4
10
40
10
10
100
4
100
400
10
40
400
10
100
1000
15
10
Magnification
Diameter field of
view (mm)
Diameter field of
view (μm)
16 a
100
1000
3
0.3 mm
0.03 mm
3000 µm
300 µm
3 µm
Nerve cell
b
Guard cells
c
Epithelial cells
d
Red blood cells
Copyright © Pearson Australia 2011 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 2356 2
Page 13
17 a
Plant
b
Animal
c
Animal
d
Plant
e
Plant
18 a
The outer layer of plant cells is the cell wall. The outer layer of animal cells is
the cell membrane.
b
Both plant cells and fungal cells have cell walls, but the walls are chemically
different.
19 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
Because plant cells can be bigger than animals cells, they would have been
more easily seen using the earliest microscopes (which were not very
powerful).
c
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.
20 a
A, D, E
21 The interconnectedness of the fibres means that all parts of the heart can work in
a coordinated way.
22
Copyright © Pearson Australia 2011 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 2356 2
Page 14
Thinking scientifically
1
C 15µm is the correct answer because it is the only one of the measurements
that falls within the boundaries of animal cells.
2
A is the correct answer because it is the only image that shows the organism
magnified two times in every direction
3
B is the correct answer because it is the only one of the shapes that could not
produce a circular cross-section.
4
D is the correct answer because after three days without water, the cytoplasm
would shrink and the cell membrane would peel away from the cell wall
(plasmolysis).
Copyright © Pearson Australia 2011 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 2356 2
Page 15