Foundational Microbiology 1: Microscopy

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Questions and Answers

Which unit of measurement is equivalent to 10-6 meter?

1 nanometer

1 centimeter

1 millimeter

1 micrometer (correct)

What is the refractive index of air?

2.5

2.0

1.5

1.0 (correct)

What is the formula for resolution?

n sin ϴ (correct)

n tan ϴ

n cot ϴ

n cos ϴ

Which objective lens has a numerical aperture of 0.1?

Scanning Signup and view all the answers

What is the approximate resolving power of the high power objective lens with light of 450 nm (blue light)?

0.9 μm Signup and view all the answers

Which type of microscope uses dark-field stop?

Dark-field microscope Signup and view all the answers

What is the approximate focal length of the low power objective lens?

40 mm Signup and view all the answers

What is the working distance of the oil immersion objective lens?

0.5-0.7 mm Signup and view all the answers

Which type of microscope is used to observe non-pigmented microbes?

Brightfield microscope Signup and view all the answers

What is the approximate resolving power of the scanning objective lens with light of 450 nm (blue light)?

0.18 μm Signup and view all the answers

Which microscopy technique uses phase contrast to enhance contrast in unstained specimens?

Differential Interference Contrast (DIC) microscopy Signup and view all the answers

Which microscopy technique uses fluorochromes to label specific cellular components?

Fluorescence microscopy Signup and view all the answers

What is the main advantage of confocal scanning laser microscopy (CSLM) over traditional light microscopy?

Ability to visualize 3D structures Signup and view all the answers

Which microscopy technique uses electron beams instead of visible light to visualize specimens?

Transmission electron microscopy Signup and view all the answers

What is the highest practical magnification of a transmission electron microscope?

Over 100,000 Signup and view all the answers

What is the best resolution of a transmission electron microscope?

0.2 nm Signup and view all the answers

What is the source of contrast in a light microscope?

Differential light absorption Signup and view all the answers

What is the source of contrast in a transmission electron microscope?

Scattering of electrons Signup and view all the answers

What is the main advantage of confocal scanning laser microscopy (CSLM) over fluorescence microscopy?

Ability to visualize 3D structures Signup and view all the answers

What is the main disadvantage of transmission electron microscopy compared to light microscopy?

Inability to visualize live samples Signup and view all the answers

Study Notes

Units of Measurement

1 micrometer (μm) is equivalent to 10^-6 meter

Refractive Index

The refractive index of air is approximately 1

Microscope Objectives

The formula for resolution is not specified, but it will be added once provided
The scanning objective lens has a numerical aperture of 0.1
The high power objective lens has an approximate resolving power of 0.2 μm with light of 450 nm (blue light)
The low power objective lens has an approximate focal length of 40 mm
The oil immersion objective lens has a working distance of approximately 0.01 mm

Microscope Types

Dark-field microscope uses a dark-field stop
Phase contrast microscope uses phase contrast to enhance contrast in unstained specimens
Fluorescence microscope uses fluorochromes to label specific cellular components
Confocal scanning laser microscopy (CSLM) uses laser beams and has the main advantage of increased resolution and depth of field over traditional light microscopy
Transmission electron microscope (TEM) uses electron beams instead of visible light to visualize specimens and has the main advantage of higher resolution and magnification over light microscopy
TEM is used to observe non-pigmented microbes

Microscope Resolution

The resolving power of the scanning objective lens with light of 450 nm (blue light) is approximately 0.5 μm
The highest practical magnification of a transmission electron microscope is approximately 1,000,000x
The best resolution of a transmission electron microscope is approximately 0.2 nm

Contrast in Microscopy

The source of contrast in a light microscope is the difference in refractive indices between the specimen and the surrounding medium
The source of contrast in a transmission electron microscope is the difference in electron density between the specimen and the surrounding medium

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Description

Test your knowledge of microscopy in this quiz! Learn about the units of measurement used in microbiology, the refractive index, and other key variables. Brush up on your understanding of microscopy techniques and sharpen your skills in this informative quiz.