Year 11 Biology

Module 1:
Cells as the Basis of Life
Cell Structure
Inquiry question 1:
What distinguishes one cell from another?

Student Workbook
 Syllabus References: Content
M1IQ1: Cell Structure
Inquiry question 1: What distinguishes one cell from another?
Students:
● M1IQ1.1: investigate different cellular structures, including but not limited to:
– M1IQ1.1.1: examining a variety of prokaryotic and eukaryotic cells
– M1IQ1.1.2: describe a range of technologies that are used to determine a cell’s structure
and function
● M1IQ1.2: investigate a variety of prokaryotic and eukaryotic cell structures, including but not
limited to:
– M1IQ1.2.1: drawing scaled diagrams of a variety of cells
– M1IQ1.2.2: comparing and contrasting different cell organelles and arrangements
– M1IQ1.2.3: modelling the structure and function of the fluid mosaic model of the cell
membrane
Index – Cell Structure
Inquiry question 1: What distinguishes one cell from another?
Worksheets / Activities Tick when done
1 Cells
2 Technologies for Studying Cells – Microscopy
3 Guidelines for Biological Drawings
4 Drawing Scale Models of Cells
5 Questions on Cell Sizes
6 Questions on the Light Microscope
7 Microscope Calculations
8 Experiment: Practical Introduction to Using a Microscope
9 Structure of Membranes
10 Build a Model of the Cell Membrane

Glossary
terminology cells cells microscope membranes
Distinguish prokaryotic Membrane-bound organelle Magnification Fluid-mosaic model
Investigate eukaryotic Cytoplasm Field of view (FOV) Peripheral protein
Technology Cell organelle Nucleus Field diameter (dFOV) Integral protein
Structure Bacteria Protein synthesis Scanning electron microscope (SEM) Phospholipid bilayer
Function Archaea Ribosome Transmission Electron Microscope Hydrophilic
Compare Eubacteria Mitochondria (TEM) Hydrophobic
Contrast Cortex (cortical) cell Endoplasmic reticulum Light microscope Lipophilic
Accuracy parenchyma Vacuole Dissecting microscope lipophobic
Validity Nucleoid DNA Stereo microscope
Reliability Pilus Scaled diagram
Flagellum Parts of a microscope
 #1 - Cells
Syllabus References: Content Syllabus References: Outcomes
M1IQ1.1: Investigate different cellular structures, including but not limited to: 11-5: Analyses and evaluates primary and secondary
- M1IQ1.1.1: examining a variety of prokaryotic and eukaryotic cells data and information
M1IQ1.2: Investigate a variety of prokaryotic and eukaryotic cell structures, including but not limited to: - 11-5.1 Derive trends, patterns and relationships in
- M1IQ1.2.2: comparing and contrasting different cell organelles and arrangements data and information

By the end of this sequence of activities students should be able to:

1. Briefly describe why, in terms of differences in cell size, a eukaryotic cell is structurally more complex and
compartmentalised than a cell that is prokaryotic.
2. When given a description, determine whether a cell is prokaryotic or eukaryotic and explain why.
3. Name the structures and make observations to describe differences in prokaryotic and eukaryotic cells
4. Identify cell organelles from a micrograph and describe the function of cell organelles
5. Identify the arrangement of cell organelles in eukaryotes
6. Compare structures present in prokaryotes and eukaryotes

What are cells

view an interactive website investigating a hand to inside cells at:
Power of Ten (1977) video starting at 6:00 minutes

Cells are the most basic or fundamental living unit for life. Different cells specialise in different
functions. Our organs are made up of many millions of cells, usually a combination of cells with
different functions (specialisations). Within cells, there are organelles. You can think of organelles
are the ‘organs’ (parts) of your cells.
The image below is of an ANIMAL cell and its Both eukaryotic cells and prokaryotic cells have
organelles. This is a eukaryotic cell, because a cell membrane. However, prokaryotic cells
all eukaryotic cells have membrane-bound lack a true nucleus that isolated genetic
organelles (e.g. mitochondria) and it has a true material (DNA/RNA) from its organelles.
nucleus that isolates its DNA material from the Also prokaryotic cells DO NOT have
rest of the organelles in the cytoplasm. membrane-bound organelles (i.e. structures in
cell do not have a membrane on the outer layer
eg ribosomes – both types of cells have these).
As you can see from the diagram, the
cytoplasm is a fluid medium that occupies many
organelles in your cell. The cell membrane
encloses the cytoplasm of a cell.
The nucleus stores DNA and transmits
appropriate information for the appropriate cell
activities to be executed. This includes
controlling the process of protein-synthesis (the
making of proteins) which makes up an
organism’s functions, appearance and
behaviour. The nucleus also controls cell
reproduction. Each cell has a nucleus and many
organelles.
Some of organ shown in the above animal cell
diagram are the mitochondria and vacuole.
Cells make up organs and an organism’s
tissues.

Generally, multicellular organisms (organisms made up of more than one cell such as humans)
have eukaryotic cells and unicellular organisms have prokaryotic cells.

Use these notes and your own research to answer the following questions:
Questions on Cells
1. Outline: The Cell Theory.

2. There are two main types of cells:

Type

Definition

Complexity

Size

• •
• Archaea •
Examples
•
•

3. When distinguishing between the two main types of cells the phrase “membrane-bound
organelle” is used. What does this mean?

4. (a) Label the different parts of the prokaryotic cell below.

Cell wall
Cell membrane
Cytoplasm
Ribosome
Nucleoid DNA
Capsule
Pilus
Flagellum

(b) Identify the function of the different parts of a prokaryotic cell.

5. Two main types of eukaryotic cells are plant and animal cells.
 (a) Label the different parts of the plant and animal cells below.

(b) Identify the function of the different parts of a plant and animal cell.
(c) Identify three main features that are different between animal and plant cells.
(d) Identify another group of eukaryotic organisms (not plants, not animals).

6. Use a Venn diagram to compare prokaryotic and eukaryotic cells.

7. Write a paragraph comparing and contrasting prokaryotic and eukaryotic cells. Your answer
should refer to: organelles/structure and their function, arrangement (where they are located)
and size.

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 #2 - Technologies for Studying Cells – Microscopy
Syllabus References: Content Syllabus References: Outcomes
M1IQ1.1: investigate different cellular 11-1 Develops and evaluates questions and hypotheses for scientific investigation
structures, including but not limited – 11-1.1 Develop and evaluate inquiry questions and hypotheses to identify a concept that can be investigated
to: scientifically, involving primary and secondary data
- M1IQ1.1.2: describe a range of 11-3 Conducts investigations to collect valid and reliable primary and secondary data and information
technologies that are used to – 11-3.3 Select and extract information from a wide variety of reliable secondary sources and acknowledge them
determine a cell’s structure and using an accepted referencing style
function 11-7 Communicates scientific understanding using suitable language and terminology for a specific audience or
purpose
- 11-7.1 Select and use suitable forms of digital, visual, written and/or oral forms of communication

By the end of this sequence of activities students should be able to:

1. Name at least two light & two electron microscopes
2. Identify the type of microscope that is used for a particular given image
3. Describe four technologies including; the type of image, the cellular structures visible, functions able to be
determined, the magnification, & the advantages & disadvantages of the technology.
4. Write a report text for one microscope & include a bibliography showing reliability of sources.
5. Extract information from valid & reliable sources
6. Develop a series of inquiry questions for their secondary research
From Simple to Compound microscopes
The compound microscope had two lenses – objective and eyepiece lens. This produced greater degree of
magnification compared to the single sense magnifying glass (simple microscope). Due to the introduction
of compound microscope, there is enough magnification power to observe cell structures such as cells that
cannot be done using a simple microscope (used by Leonardo).
Introduction and use of the electron microscope
Electron microscope employs beams of electrons to either analyse the surface of a specimen, providing
information regarding the surface landscape and chemical composition. It can also be used to observe the
complex, internal structure of cell specimens and their organelles. Cell structure if often considered to be
related to cell function. The discovery of the structural similarities between the endoplasmic reticulum and
peroxisomes organelles led to the understanding of how these organelles allowed proteins to travel
between these organelles and were responsible for peroxisome biogenesis disorder (disease).
Furthermore, electron microscopy can be used to locate and track molecules and compounds in the body
to further our understanding on chemical reaction pathways. By doing so, more information is revealed
about how molecules and compounds react with cells and its organelles & vice versa. Overall, the electron
microscope provides scientists with greater understanding of the structure and function of cells.
Other technologies used to observe cells:
transmission electron microscope confocal microscopy helium microscope
scanning electron microscope X-ray crystallography radioisotopes
phase-contrast optical microscopy DNA analysis bright-field microscopy
differential interference-contrast microscopy Biomarkers

Use the following websites as a starting point to research information about light and electron microscopes:
- Microscopy http://www.biologymad.com/master.html?http://www.biologymad.com/cells/cells.htm
- Types of Microscopes
http://www.cas.miamioh.edu/mbiws/microscopes/types.html
- Difference between a Light Microscope and an Electron Microscope http://theydiffer.com/difference-
between-a-light-microscope-and-an-electron-microscope/
- Light Microscope vs Electron Microscope
http://www.ivyroses.com/Biology/Techniques/light-microscope-vs-electron-microscope.php
- Differences between TEM and SEM
http://www.majordifferences.com/2016/08/difference-between-sem-and-tem.html#.WnbdbeeYPDc
- Resolution
http://www.cas.miamioh.edu/mbiws/microscopes/resolution.html

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 Questions on Technologies for studying cells
1. Construct and complete a table like the one below for each of the following types of microscopes:
Compound Microscope, Dissecting Microscope, Scanning Electron Microscope (SEM), Transmission
Electron Microscope (TEM)

Type of
Technology

How it Works

Magnification
& Resolution

Energy Source

Specimen
Preparation

Type of Image

Uses

Advantages

Disadvantages

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2. Identify which type of electron microscope (SEM or TEM) or optical microscope (compound or
dissecting) was used to produce each of the images in the photos below (A-H).

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 #3 - Guidelines for Biological Drawings
Syllabus References: Content Syllabus References: Outcomes
M1IQ1.2: investigate a variety of 11-4 Selects and processes appropriate qualitative and quantitative data and information using a range of
prokaryotic and eukaryotic cell appropriate media:
structures, including but not limited to: - 11-4.1 Select qualitative and quantitative data and information and represent them using a range of formats,
- M1IQ1.2.1: drawing scaled diagrams digital technologies and appropriate media
of a variety of cells - 11-4.2 Apply quantitative processes where appropriate
11-5 analyses and evaluates primary and secondary data and information
- 11-5.1 Derive trends, patterns and relationships in data and information
11-7 communicates scientific understanding using suitable language and terminology for a specific audience or
purpose
- 11-7.1 Select and use suitable forms of digital, visual, written and/or oral forms of communication

By the end of this sequence of activities students should be able to:

1. Use a light microscope safely
2. Understand the function of the parts of the microscope
3. Observe different types of cells e.g. nerve, muscle, skin, guard cells, bacteria
4. Draw a scaled diagram of different types of cells e.g. nerve, muscle, skin, guard cells, bacteria
5. Convert cm to mm to nm & vice versa
6. Use quantitative analysis when determining the scale for a diagram

Microscopes are a powerful tool for examining cells and cell structures. In order to make a
permanent record of what is seen when examining a specimen, it is useful to make a drawing. It is
important to draw what is actually seen. This will depend on the resolution of the microscope being
used. Resolution refers to the ability of a microscope to separate small objects that are very close
together. Making drawings from mounted specimens is a skill. Drawing forces you to observe
closely and accurately. While photographs are limited to representing appearance at a single
moment in time, drawings can be composites of the observer’s cumulative experience, with many
different specimens of the same material. The total picture of an object thus represented can often
communicate information much more effectively than a photograph. Your attention to the outline of
suggestions below will help you to make more effective drawings. If you are careful to follow the
suggestions at the beginning, the techniques will soon become habitual.

1. Drawing Materials: All drawings should be done with a clear pencil line on good quality paper.
A sharp HB pencil is recommended. A soft rubber of good quality is essential. Diagrams in
ballpoint or fountain pen are unacceptable because they cannot be corrected.

2. Positioning: Centre your diagram on the page. Do not draw it in a corner. This will leave plenty
of room for the addition of labels once the diagram is completed.

3. Size: A drawing should be large enough to easily represent all the details you see without
crowding. Rarely, if ever, are drawings too large, but they are often too small. Show only as much
as is necessary for an understanding of the structure – a small section shown in detail will often
suffice. It is time consuming and unnecessary, for example, to reproduce accurately the entire
contents of a microscope field.

4. Accuracy: Your drawing should be a complete, accurate representation of the material you
have observed, and should communicate your understanding of the material to anyone who looks
at it. Avoid making “idealised” drawings – your drawing should be a picture of what you actually
see, not what you imagine should be there. Proportions should be accurate. If necessary, measure
the lengths of various parts with a ruler. If viewing through a microscope, estimate them as a
proportion of the field of view, then translate these proportions onto the page. When drawing
shapes that indicate an outline, make sure the line is complete. Where two ends of a line do not
meet (as in drawing a cell outline) then this would indicate that it has a hole in it – ruptured.
5. Technique: Use only simple, narrow lines. Represent depth by stippling (dots close together).
Indicate depth only when it is essential to your drawing (usually it is not). Do not use shading. Look
at the specimen while you are drawing it.

6. Labels: Leave a good margin for labels. All parts of your diagram must be labelled accurately.
Labelling lines should be drawn with a ruler and should not cross. Where possible, keep label lines
vertical or horizontal. Label the drawing with:
• A title, which should identify the material (organism, tissues or cells).
• Magnification under which it was observed, or a scale to indicate the size of the object.
• Names of structures.
• In living materials, any movements you have seen.

Remember that drawings are intended as records for you, and as a means of encouraging close
observation; artistic ability is not necessary. Before you turn in a drawing, ask yourself if you know
what every line represents. If you do not, look more closely at the material. Take into account the
rules for biological drawings and draw what you see – not what you think you see!.

Examples of acceptable biological drawings: The diagrams below show two examples of biological
drawings that are acceptable. The example on the left is a whole organism and its size is indicated
by a scale. The example on the right is of plant tissue – a group of cells that are essentially
identical in the structure. It is not necessary to show many cells even though your view through the
microscope may show them. As few as 2-4 will suffice to show their structure and how they are
arranged. Scale is indicted by stating how many times larger it has been drawn. Do not confuse
this with what magnification it was viewed at under the microscope. The abbreviation T.S.
indicates that the specimen was a transverse section as opposed to a cross section.

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Questions on Guidelines for Biological Drawings

1. Identify and describe 8 unacceptable features of the student’s biological diagram above.

2. In the remaining space next to the ‘poor example’ (above) or on a blank piece of refill paper, attempt
your own version of a biological drawing for the same material, based on the photograph above.
Make a point of correcting all of the errors that you have identified in the sample student’s attempt.

3. State why careful, accurate biological drawings are more valuable to a scientific investigation than
an ‘artistic’ approach.

4. Use ths weblink to draw an Amoeba to scale.

https://www.youtube.com/watch?v=7pR7TNzJ_pA

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#4 - Drawing Scale Models of Cells
Introduction:
Cells appear in all shapes and sizes. Cells are so small they are measured in micrometres
(sometimes referred to as microns). The symbol for a micrometre is µm and it is equal to one
millionth of a metre or one thousandth of a millimetre.
Reviewing Measurements:
1 metre = 1000 millimetres (mm)
1 millimetre = 1000 micrometres (µm)
1 micrometer = 1000 nanometres (nm)
Eukaryotes include all animals, plants, algae and protists. Prokaryotes include Eubacteria and
Archaea (also called Archaebacteria or extremophiles). Are bacterial cells similar in size to plant
and animal cells? This activity is designed to assist you to become aware of the relative scale of
various types of cells.
Aim:
To make a scale drawing of some cell types.

Materials:
Centimetre ruler
Pencil
Large sheet of butcher’s paper (or A3 paper)

Method:
1. Complete the table below.
(a) Use a scale factor of 1 micrometre = 0.5 cm to calculate the model size.
(b) Research the shape of each type of cell. It will usually be spherical or rectangular in shape.

Cell Type Average Size (μm) Model Size (cm) Shape of Cell
Eukaryote
- human white blood cell 15
- cheek epithelium cell 60
- adipose fat tissue cell 30
- cortical plant cell 50

Prokaryote
- Bacillus bacterium 4
- Staphylococcus bacterium 1

2. Draw a line 0.5 cm long in one corner of the butcher’s paper. This will be your scale bar that
represents 1 micrometre (μm).

3. Draw a series circles/rectangular shapes on the butcher’s paper to represent the average size
of the various cells identified in the table. Ensure your cells are labelled.

Conclusion:
Given that these examples are typical, what conclusion can be drawn about the relative size of
bacterial cells compared with cells of eukaryotes?
Links for cell types (use these to find cells to draw)

Human white blood cell

https://www.google.com.au/search?q=human+white+blood+cell&client=firefox-b-
ab&dcr=0&source=lnms&tbm=isch&sa=X&ved=0ahUKEwidoML_84HZAhXJNpQKHS31AtoQ_AUI
CigB&biw=880&bih=552

Cheek epithelial cell

https://www.google.com.au/search?q=cheek+epithelial+cell&client=firefox-b-
ab&dcr=0&tbm=isch&source=iu&ictx=1&fir=6aRYRohrJc0dRM%253A%252CQfy4hjSyIR7t1M%25
2C_&usg=__LSx9GC9mMii8Sb_M0oGwqWTOSLQ%3D&sa=X&ved=0ahUKEwiNwZuF84HZAhXI
tpQKHZpbCeYQ9QEILzAC#imgrc=6aRYRohrJc0dRM:

Adipose fat tissue cell

https://www.google.com.au/search?q=adipose+fat+tissue+cell&client=firefox-b-
ab&dcr=0&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjexrDB84HZAhVBlpQKHXo7DioQ_AUI
CigB&biw=880&bih=552

Cortical plant cell

https://www.google.com.au/search?client=firefox-b-
ab&dcr=0&biw=880&bih=552&tbm=isch&sa=1&ei=N45xWqq5Nce30gSRqaCYBw&q=cortical+pla
nt+cell&oq=cortical+plant+cell&gs_l=psy-
ab.3...44111.50933.0.51796.0.0.0.0.0.0.0.0..0.0....0...1c.1.64.psy-ab..0.0.0....0.8QEl-AkI7F4

google definition of cortex cell : In botany, the cortex is the outermost layer of the stem or root of a
plant, bounded on the outside by the epidermis and on the inside by the endodermis. In plants, it
is composed mostly of differentiated cells, usually large thin-walled parenchyma cells of the
ground tissue system. So we could look at parenchyma cells instead.

Parenchyma cells
https://www.google.com.au/search?q=parenchyma+cells&client=firefox-b-
ab&dcr=0&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi0wsyjzI3ZAhWBW7wKHchGDhwQ_AU
ICigB&biw=1036&bih=548#imgrc=zEDABt_BsaRjIM:

Bacillus bacterium
https://www.google.com.au/search?q=bacillus+bacterium&client=firefox-b-
ab&dcr=0&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjR_M2W9IHZAhWKmZQKHWqfAnQQ_
AUICigB&biw=880&bih=552

Staphyllococcus bacterium
https://www.google.com.au/search?q=Staphylococcus+bacteria&client=firefox-b-
ab&dcr=0&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiT2Py19IHZAhVBmZQKHZ8lAOEQ_AU
ICigB&biw=880&bih=552
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#5 - Questions on Cell Sizes
Suggestion: measure scale length and length of organism.
#6 - Questions on using the Light Microscope
1. Label the parts of the microscope and identify the function.

2. Arrange the steps for focusing a microscope in the correct order.

• Adjust the fine focus knob to clearly focus the image.

• Turn the nosepiece to set the objective lens on required power eg. x10.

• Plug in and turn on the lamp.

• Place a prepared slide on the stage, clipping it into place with stage clips.

• Look through the eyepiece (ocular lens), down the tube and slowly wind back the coarse
focus knob until the image comes into focus.

• While looking from the side, wind down the tube using the coarse focus knob till the
objective lens is almost touching the slide.
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#7 - Questions on Microscope Calculations
Total Magnification = Magnification of the eyepiece lens X Magnification of the objective lens

Drawing Magnification = Diagram Size/Actual Size

Size = Field of view/Number of cells that fit across the field of view

Total Magnification

1. Complete the table below to calculate the total magnification.

Ocular (Eyepiece) Objective Total Magnification
10X 4X
15X 10X
5X 12X
10X 10X
10X 40X

Drawing Magnification

2. Complete the table below. (Be careful with the units! Show working)
Actual Specimen Size Drawing Size Drawing Magnification
0.5 mm 2 cm
200 m 1 cm
40 m 2 cm
100 m 200X
5 cm 100X
4 cm 50X

3. A student sketches an organism and the sketch is 5.0 cm long. The actual size of the organism
is 200 m.
(a) 5.0 cm = ________ mm = ________ m
(b) Calculate the drawing magnification.

4. The drawing magnification of a sketch is 200X and the actual size of the object is 100 m.
(a) Calculate the length of the drawing in m.
(b) Calculate the drawing size in mm ________ in cm ________

5. A student, observing a micro-organism under a magnification of 40X, calculates that it is about

100m long.
(a) If she then draws the micro-organism 2 cm long, what is the magnification of her drawing?
(b) If her partner draws the micro-organism at a magnification of 1000X, how long will the
drawing be?
Estimating Cell Size

6. The field of view is 2500μm. If a cell takes up 1/5 of the field of view, how long is the cell?

7. A student counts 50 cells across the diameter of the field of view, and there are 70 rows of
cells. If the diameter of the field of view is 3500 μm, what is the length and width of the cells?

8. Look at the diagram. There is an object called a Paramecium that fits half way across the field.
Object measured in field of view
at x100 magnification

(a) How long is the Paramecium?

(b) How wide is the Paramecium?

(c) If you had an organism under the

microscope that you estimated fitted across the
field four times, how big would it be?

9. The diameter of the field of view is 1200μm.

Estimate the length of the living thing in the
diagram on the right hand side.

10. The medium Power Field Diameter on a certain microscope is 1600 μm. An object’s length
measures 1/3 of the diameter of the field. Calculate the actual size of the object in μm.

11. The picture shows five organisms stretched

across the High Power Field of a
microscope. The High Power Field Diameter
of this microscope is 400 μm. Calculate the
actual size of one of these organisms.
12. You are in an Anatomy and Physiology lab observing onion cells under a microscope.
Answer the following questions.

- Magnification of the ocular lens of your microscope is 10X

- low power (magnification of objective lens is 5X)
- medium power (magnification of objective lens is 10X)
- high power (magnification of objective lens is 50X)
- oil immersion (magnification of objective lens is 100X)

If the FOV under low power is 3.65 mm, calculate FOV (in μm) for:
(a) medium power
(b) high power
(c) oil immersion

13. The magnification of the ocular lens of a microscope is x10 and the magnification of the
objective lens for low, medium, and high power are 4X, 10X, and 40X, respectively. The
measured FOV under medium power is 2.6mm. If 15 cells are observed across the FOV under
the high power, how long is each cell (in μm to the nearest whole number)?

14. What is the size of the object (in μm)? Round to the nearest whole number.

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#8 - Experiment: Practical Introduction to Using a Microscope
Background information:
(Risk Assess 11BIOM1 Practical Introduction to Using a Microscope)
The compound light microscope has been the principal tool used by biologists for the past 300
years. It magnifies objects and biologists can measure the size of living cells and also observe
certain structures within cells. In this investigation the skill of using the light microscope will be
developed.

Aims:

- To prepare a wet mount of onion epidermal cells and elodea cells.

- To measure the field of view in each magnification of the microscope.
- To estimate the actual size of a range of cells.
- To investigate the structure of a range of prokaryotic and eukaryotic cells and draw biological
diagrams of these.

Materials:

- Microscope
- Prepared slides of cells (e.g. cheek cells)
- Onion
- Pond Weed – Elodea
- Microscopic organisms (e.g. Paramecium)
- Iodine
- Forceps
- Glass slides and cover slips
- Minigrid

Risk Assessment

Hazard Risk Precaution

Part A: Preparing a Wet Mount of Onion Epidermal Cells and Elodea Cells

Method:
1. Place a clean glass slide on a paper towel on a bench.
2. With a forceps place a thin specimen of the onion on the slide.
3. Immediately place a drop of iodine onto the specimen.
4. Place the cover slip (at an angle) on the slide eliminating as many air bubbles as possible.
5. View the onion cells under low power then high power magnification.
6. Draw a labelled diagram of what you see.
7. Repeat the procedure for Elodea BUT DO NOT stain them.
8. Video https://www.youtube.com/watch?v=XKPdnE6BGew
Part B: Measuring the Field of View (FOV)

Method (assumes use of digital microscope):

1. Turn on the light and adjust the iris diaphragm on your microscope to form a clear ‘circle of
light’.
2. Put a mini grid in the centre of the stage and secure it with the stage clips.
3. Adjust the coarse focus until the 4X lens (scanning objective) and stage are brought as close
together as possible.
4. Look through the eyepiece and adjust the coarse focus until the mini grid comes into view.
5. Adjust the fine focus slowly until the large squares with 1mm sides come into sharp focus.
6. Align the grid in such a way that a line corresponding a millimetre “touches” the left side of the
field of view. Take a photo.
7. Use the mini grid to estimate the diameter of field of view at this magnification (i.e. 40X) in
millimetres and micrometres.
8. Establish a magnification of 100X (low power) and estimate the diameter of field of view at
100X. Take a photo.
9. We cannot repeat the procedure for the 40X objective lens (high power) because the size of
the field of view (FOV) is smaller than one millimetre, but the diameter of a high power field
can be calculated by dividing your 10x field by 4 as the high power field is a ¼ of the low
power field.

Results:
Total Magnification Field of View (mm) Field of View (μm)
X
X
X

Question:
1. What is the relationship between the magnification power used and the size of the field of view
(FOV) or area observed under the microscope?

Part C: Estimating the actual size of a range of cells

Method:
1. Focus the prepared (e.g. cheek) slide under low power.
2. Focus the prepared slide under high power and observe the cells more closely. Take a photo.
3. Count the number cells along the diameter of the field of view and record the number.
4. Calculate the size of a cell by dividing the field of view size by the number of cells that fit
across the diameter.
5. Repeat steps 1-4 for TWO other cell types.

Results:

Field of View # of Times the Cell Size (μm)

Specimen
(FOV) (μm) Fits Across FOV (FOV/# of Times the Cell Fits)
Questions:
1. Describe 2 sources of error in this experiment. What, if anything could be done to minimise
these sources of error (improve the method to ensure the results are accurate)?
2. Compare your results to those in secondary sources and assess the reliability of this
investigation.

Part D: Drawing Cells Seen Under the Microscope, Identifying Structures

Method:
1. View each of the slides under the microscope. Take a photo of each specimen.
2. For each slide that you observe include the following:
a) Careful and accurate scale drawing of 2 or 3 representative cells.
b) Title above drawing which accurately identifies the specimen
c) Magnification below specimen (e.g., 100x)
d) Names of known or identifiable structures, with lines connecting the structures to their
labels
Questions:
1. Complete the following information regarding the cellular structures observed in plant and
animal cells under the microscope.
(a) ONLY present in plants cells. (2)
(b) Present in BOTH cellular types. (3)
2. List the organelles that cannot be seen under the light microscope. Explain why they cannot be
seen.
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 #9 - Structure of Membranes
Syllabus References: Content Syllabus References: Outcomes
M1IQ1.2: investigate a variety of prokaryotic and eukaryotic cell 11-6 Solves scientific problems using primary and secondary data, critical thinking
structures, including but not limited to: skills and scientific processes
- M1IQ1.2.3: modelling the structure and function of the fluid mosaic - 11-6.1 Use modelling (including mathematical examples) to explain phenomena,
model of the cell membrane make predictions and solve problems using evidence from primary and
secondary sources

By the end of this sequence of activities students should be able to:

1. Explain how the model shows that the cell membrane regulates what moves into and out of cells
2. Assess the relevance of aspects of the model
3. Draw & label a 2D diagram of a fluid mosaic model of a membrane using scientific terminology (including all
surface molecules)

Read the Powerpoint: Cell Membranes.pptx

Watch the Videos:
The Plasma Membrane and the Fluid Mosaic Model https://www.youtube.com/watch?v=CNbZDcibegY
Fluid Mosaic Model of the Cell Membrane https://www.youtube.com/watch?v=LKN5sq5dtW4

The Fluid Mosaic Model

The cell membrane surrounds every cell and
controls the substances that go in and out of the
cell. The cell membrane is said to be “selectively
permeable”.
The fluid mosaic model describes the structure of
the membrane and accounts for the way
membranes allow materials to move across by
both active and passive means.
The fluid mosaic model describes the membrane in
the following way:
➢ consists of a thin sheet made up of 2 layers
(bilayer) of lipids called phospholipids and
proteins scattered throughout
➢ the lipids are composed of a hydrophilic-
lipophobic (water loving/polar) head and a
lipophilic-hydrophobic (fat loving/non polar) tail
➢ the proteins are of two types:
(1) peripheral proteins – are attached to the
surface
(2) integral proteins – extend from one side to
the other, or only part way across the bilipid
layer
Lipid soluble substances e.g. carbon dioxide, oxygen diffuse across the lipid bilayer. Tiny molecules
such as water and some ions diffuse across through small openings made by the movement of the fluid
lipids. Large water soluble molecules e.g. amino acids and simple sugars combine with transport
integral proteins and are ‘carried’ across the membrane by facilitated diffusion
a labelled diagram to describe the phospholipid bilayer.
 Questions on Structure of Membranes
1. Identify TWO roles of the cell membrane.

2. What does semi-permeable mean with respect to cell membranes?

3. Describe the structure of membranes.

4. Label the diagram below of the fluid mosaic model of the cell membrane, using the following words to
fill in the boxes: phospholipid bilayer, integral protein, peripheral protein, glycolipid, glycoprotein,
cholesterol, fatty acid tail, phosphate head. Colour-code your diagram to show hydrophobic regions
of the membrane and hydrophilic regions in different colours.

5. Define the terms hydrophilic and hydrophobic.

6. Where are carbohydrates found in membranes? What is their purpose?

7. Where are cholesterol molecules found in membranes? What is their purpose?

8. Describe TWO roles of membrane proteins.

9. Identify which molecules pass through (a), (b) and (c).

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Adapted From: Build a Model of the Cell Membrane: https://www.education.com/science-fair/article/build-cell-membrane-model/

#10 - Build a Model of the Cell Membrane

(Risk Assess 11BIOM1 Build a Model of the Cell Membrane)
Introduction:
The cell membrane is a barrier that separates a cell from the external environment. It controls the
passage of materials into and out of the cell. The membrane is made up of a double layer of
phospholipids, called the lipid bilayer. Scattered between these phospholipids are various other
molecules such as protein channels, pumps, cholesterol, and carbohydrate chains. With the
cooperation of the phospholipids and other embedded molecules the passage of molecules into and
out of the cell is controlled. Think of the cell membrane as the exterior walls and roof of your home. It’s
scattered with a number of windows, doors and vents. Just like the cell, these items help to control
what enters and exits your home.

Aims:
To build a model of the cell membrane.
To investigate how the cell membrane regulates what moves
into and out of cells.

Materials:
• 3 pipe cleaners of different colours
• 1 regular-sized drinking straw
• Thick, medium-size rubber band
• Approximately 50 cotton swabs
• Scissors
• 1 marble
• 1 BB or small metal ball

Method:
1. Gather the cotton swabs into a bundle and place the rubber band around the middle to keep them
in a bundle. What molecules of the cell membrane do the cotton swabs represent?
2. Place a receptor molecule into the cell membrane.
(a) Take one of the pipe cleaners and place it through the bundle of cotton swabs.
(b) Bend one end of it into a circular shape. This shape represents how signal molecules bind to
specific molecules. Only a circular-shaped molecule can bind with this receptor.
3. Use the second pipe cleaner as a carbohydrate chain. Place it in the bundle of cotton swabs, just
as in step 2. Don’t bend this pipe cleaner.
4. Cut your drinking straw in half. Place each half into different locations in the bundle of cotton
swabs. These represent the protein channels and pumps.
5. Holding the cotton swabs vertically, place the marble on top of the swabs. Does it pass between
the swabs? Why or why not?
6. Place the marble on top of the straw. Does it pass through the straw? Why or why not?
7. Still holding the cotton swabs vertically, place the BB on top of the swabs. Does it pass between
the swabs? Why or why not?
8. Place the BB on top of the straw. Does it pass through the straw? Why or why not?
9. Place your mouth on the cotton end of the swabs and blow. Can you feel air on the other side of
the swabs? Why or why not?
10. Explain how the swabs and straws actually represent the components of a real cell membrane.
11. Roll the bundle of cotton swabs between your hands. Do the individual swabs move? Without
pulling the straw out can you move it between the swabs? How does this represent the fluid mosaic
model?

Question:
Assess the model made. Use the questions asked in the method to help you answer this question.
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