29 questions · 29 marks · ≈ 29 min
Which of the statements about light microscopes are correct?
| 1 | The magnification of a light microscope is limited by the wavelength of light |
|---|---|
| 2 | The resolution of a light microscope is limited by the wavelength of light |
| 3 | To calculate the magnification of a light microscope the eyepiece lens and objective lens magnifications are added together |
Choose your answer
1 and 2
1 and 3
2 and 3
1, 2 and 3
Which row correctly describes the magnification and resolution of an electron microscope in relation to a light microscope?
| magnification | resolution | |
|---|---|---|
| A | lower | higher |
| B | higher | lower |
| C | higher | higher |
| D | lower | lower |
Choose your answer
At approximately which magnification would the resolution of a light microscope become too low to produce a clear image?
Choose your answer
100
200
x 400
1500
Which of the following is not a step involved in the preparation of an onion cell specimen for viewing under a light microscope?
Choose your answer
Place one edge of a coverslip on the slide and carefully lower the rest of the coverslip onto the specimen
Add a drop of iodine stain
Remove a layer of onion tissue that is one cell thick from a piece of onion
Add a drop of methylene blue stain
Specimens can be measured using eyepiece graticules and stage micrometers.
Which of the following correctly describes the role of a stage micrometer?
Choose your answer
Directly measuring the size of a specimen
Determining the size of the eyepiece graticule units
Determining the magnification at which at object is being viewed
A type of slide upon which a specimen can be prepared
A microscope has a resolution of 200 nm.
Which of the following organelles would not be resolved by this microscope?
Choose your answer
Mitochondria
Lysosomes
Ribosomes
Chloroplasts
Which of the following is not a convention that should be used when producing biological drawings of cells?
Choose your answer
Single, clear pencil lines should be used
Shading should be used to indicate light and dark regions of cells
Label lines should not have arrow heads
At least half of the available space on the page should be taken up by the drawing
Which of the options gives the resolution, in nanometres, of an electron microscope and a light microscope?
| electron microscope | light microscope | |
|---|---|---|
| A | 5.0 | 20 |
| B | 5.0 | 200 |
| C | 0.5 | 20 |
| D | 0.5 | 200 |
Choose your answer
A lysosome has a diameter of 0.4 µm.
Which of the following gives the lysosome diameter in nm?
Choose your answer
4
40
400
4000
Which of the following correctly defines the term resolution in light microscopy?
Choose your answer
The size of the smallest object that can be seen
Twice the wavelength of the light used to illuminate the specimen
The shortest distance at which two objects can be seen as separate points
The product of the magnifications of the eyepiece and the objective lens
Which of the following descriptions of light and electron microscopes is not correct?
Choose your answer
An electron microscope has a maximum magnification of x500 000
A light microscope has a maximum resolution of 0.2 µm
An electron microscope has a maximum resolution of 0.05 nm
A light microscope can resolve specimens that measure 200 nm in diameter
A prokaryotic cell with a diameter of 1 µm is magnified 50 000 times by an electron microscope.
What is the diameter of the cell in the resulting electron micrograph?
Choose your answer
5 mm
5 x 10-1 mm
5 x 102 mm
5 x 101 mm
The electron micrograph below shows the organelles in a leaf cell, as well as a scale bar and on-screen ruler.
What is the magnification of the image?
Choose your answer
x7000
×3570
x2800
x280
The electron micrograph below shows a root vascular system.
The magnification of the image is x200 and Y has a diameter of 1 cm when measured using a ruler.
What is the diameter of the cell labelled Y?
Choose your answer
100 µm
50 µm
10 µm
5 µm
To view the actual width of a transverse section of a xylem vessel with a x40 lens, which steps are needed?
| 1 | measure the width of the xylem vessel using an eyepiece graticule |
|---|---|
| 2 | calibrate the eyepiece graticule using a stage micrometer on x10 objective lens |
| 3 | convert from mm to µm by multiplying by 10-3 |
| 4 | multiply the number of eyepiece graticule units by the calibration of the eyepiece graticule. |
Choose your answer
1 and 2
2 and 3
1 and 3
1 and 4
The electron micrograph of a bacterial cell has a 2 cm scale bar.
What is the magnification of the image?
Choose your answer
2 x 103
2 x 104
2 x 101
2 x 105
Erythrocytes (red blood cells) have a diameter of 7 000 nm. Pancreatic cells have a diameter of 35 µm.
Which of these statements about the relative sizes of these cells is correct?
Choose your answer
The erythrocytes are 5 times smaller than pancreatic cells
The erythrocytes are 50 times smaller than pancreatic cells
The erythrocytes are 5 times larger than pancreatic cells
The erythrocytes are 50 times larger than pancreatic cells
The table shows some approximate units for measuring the diameters of alveoli, white blood cells and the width of cell walls.
Which of the rows show the correct units for these structures?
| Diameter of alveoli | Diameter of white blood cells | Width of cell walls | |
|---|---|---|---|
| A | mm | µm | µm |
| B | mm | µm | nm |
| C | µm | nm | µm |
| D | µm | µm | nm |
Choose your answer
The following statements describe slide preparation.
Which statement would not be relevant in the preparation of a wet mount for observation with a light microscope?
Choose your answer
Methylene blue is added to the specimen
A coverslip is placed on the specimen
The low power lens is above the object on the stage
A drop of water is added to the specimen
The following statements describe producing a scientific drawing.
Which is not a correct statement about drawing scientifically?
Choose your answer
The magnification should be stated
Label lines should have arrowheads
White, unlined paper should be used
Lines should be drawn with a smooth continuous line
The actual length of a cellular structure is 6 µm.
A student was asked to write an equation that could be used to calculate the magnification of an electron micrograph of this cell structure. The student used the letters q to u in their equation.
q = the length of the cell structure in the image in cm
r = the length of the cell structure in the image in mm
s = 1000
t = 1/6
u = 6
Which of the following would be the correct equation to calculate the magnification?
Choose your answer
The diagram shows a stage micrometer (top) being used to calibrate an eyepiece graticule (bottom). The divisions on this micrometer measure 0.1 mm.
A slide of a plant cell was placed on the stage in place of the stage micrometer.
What is the width of a single chloroplast shown on the slide below?
Choose your answer
100 µm
50 µm
10 µm
0.5 mm
Cells can vary considerably in diameter, e.g.
Use these measurements to find the maximum number of each cell that could be arranged, end-to-end, along a 1 cm line.
| Number of white blood cells | Number of Streptococcus cells | |
|---|---|---|
| A | 6.7 x 100 | 1.3 x 102 |
| B | 6.7 x 101 | 1.3 x 103 |
| C | 6.7 x 102 | 1.3 x 104 |
| D | 6.7 x 103 | 1.3 x 105 |
Choose your answer
The image below shows an electron micrograph of a bacterial cell. The scale bar measures 2 cm and represents a length of 500 nm.
*CC BY 2.5, via *Wikimedia Commons
What is the actual length of the bacterial cell?
Choose your answer
0.002 μm
2.4 μm
24 μm
4 μm
The diagram below shows the view through an eyepiece when a stage micrometer is used. This stage micrometer (shown here at the top of the image) has divisions that are 0.1 mm apart.
The same eyepiece is used to examine a blood smear.
How many of the graticule divisions will cover the diameter of a white cell of 12.5 µm?
Choose your answer
1
4
5
10
A light microscope is used at a magnification of x400 and with a green light source that has a wavelength of 510 nm.
The same specimen is viewed again under the same conditions, but with the light source switched to red light with a wavelength of 650 nm.
What effect would this have on the magnification and resolution of the microscope?
| magnification | resolution | |
|---|---|---|
| A | stays the same | increased |
| B | stays the same | decreased |
| C | increased | decreased |
| D | decreased | increased |
Choose your answer
The diagram below shows a view through a microscope eyepiece with a graticule scale and a stage micrometer, using a magnification of x400.
Using the magnification of x400, a chloroplast was measured to be 4 eyepiece graticule divisions in length.
How long is the chloroplast?
Choose your answer
4.0 x 102 µm
2.5 x 10-1 µm
2.5 x 10-2 µm
1.0 x 101 µm
The diagram below shows a view through a microscope eyepiece with a graticule scale (bottom) and a stage micrometer (top).
What is the area of the field of view at this magnification?
Note that π = 3.14
Choose your answer
2.0 x 105 µm2
7.9 x 103 µm2
4.9 x 102 µm2
4.9 x 104 µm2
A student was using an eyepiece graticule with 100 small divisions and a stage micrometer with 50 divisions, each 0.04 mm apart.
Using a x40 objective lens, the whole length of the stage micrometer lined up with 15 divisions of the eyepiece graticule.
What is the length of the 100 division scale of the eyepiece graticule at this magnification?
Choose your answer
750 µm
75 µm
13 mm
1.3 mm