Chapter 2
Microscopy
Terms Introduced in This Chapter
After reading Chapter 2, you should be familiar with the following terms. These terms are
defined in Chapter 2 and in the Glossary.
Bacillus (pl., bacilli)
Brightfield microscope
Centimeter
Coccus (pl., cocci)
Compound light microscope
Darkfield microscope
Decimeter
Electron micrograph
Electron microscope
Empty magnification
Fluorescence microscope
Micrometer
Microscopic
Millimeter
Nanometer
Phase-contrast microscope
Photomicrograph
Resolving power (resolution)
Scanning electron micrograph
Scanning electron microscope
Simple microscope
Transmission electron micrograph
Transmission electron microscope
Critical Thinking
You are planning to create a better compound light microscope—one that will enable you
to see objects smaller in diameter than 0.2 µm. You gather together the best lens grinders
in the world and put them to work in a lens-grinding laboratory having unlimited
resources. You instruct them to grind marvelous magnifying lenses and add them to an
existing compound light microscope. What’s wrong with this plan?
Answers to the Chapter 2 Self-Assessment Exercises in
the Text
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
D
B
A
D
D
B
A
D
B
B
Additional Chapter 2 Self-Assessment Exercises
(Note: Don’t peek at the answers before you attempt to solve these self-assessment exercises.)
Matching Questions
A.
B.
C.
D.
E.
10
100
1,000
1,000,000
1,000,000,000
_____ 1.
The number of nanometers in a
micrometer.
_____ 2.
The resolving power of the compound
light microscope is __________ times
better than the resolving power of the
unaided eye.
_____ 3.
The number of micrometers in a
millimeter.
_____ 4.
The resolving power of the transmission
electron microscope is __________
times better than the resolving power of
the scanning electron microscope.
_____ 5.
The resolving power of the transmission
electron microscope is __________
times better than the resolving power of
the unaided eye.
A.
B.
C.
D.
E.
0.2 nm
20 nm
0.2 µm
1 µm
0.2 mm
_____ 6.
The width of a typical coccus.
_____ 7.
The resolving power of the unaided eye.
_____ 8.
The resolving power of the scanning
electron microscope.
_____ 9.
The resolving power of the transmission
electron microscope.
_____ 10.
The resolving power of the compound
light microscope.
True/False Questions
_____ 1.
Anton van Leeuwenhoek is given credit for developing the first compound light
microscope.
_____ 2.
The wavelength of visible light limits the size of objects that can be seen with the
compound light microscope.
_____ 3.
The resolving power of compound light microscopes can be improved by adding
additional magnifying lenses.
_____ 4.
A brightfield microscope can be converted to a darkfield microscope by replacing
the condenser on a brightfield microscope with a darkfield condenser.
_____ 5.
Transmission electron microscopes are used to study surface features.
_____ 6.
Primary syphilis is usually diagnosed in the clinical microbiology laboratory by
the use of a scanning electron microscope.
_____ 7.
A magnifying glass could be considered a simple microscope.
_____ 8.
The total magnification achieved when the oil immersion lens is used is 1,000.
_____ 9.
Fluorescence microscopy is often used in immunology laboratories.
_____ 10.
The resolving power of electron microscopes is much better than that of
compound light microscopes because the wavelength of electrons is much longer
than that of visible light.
Answers to the Additional Chapter 2 Self-Assessment
Exercises
Matching Questions
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
C
C
C
B
D
D
E
B
A
C
True/False Questions
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
False (Leeuwenhoek made simple microscopes, not compound microscopes)
True
False (adding additional magnifying lenses to existing compound light microscopes
would not improve resolving power; it is referred to as “empty magnification”)
True
False (transmission electron microscopes are used to observe internal structures; scanning
electron microscopes are used to study surface features)
False (primary syphilis is usually diagnosed using darkfield microscopy)
True
True
True
False (it is because the wavelength of electrons is much shorter than that of visible light)