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WorksheetsChapter 3 Observing Microorganisms Through a Microscope
Total questions: 25
Worksheet time: 13mins
What does the term resolution (resolving power) refer to in microscopy?
The ability to magnify an image
Minimum distance between two objects where you can still see them as separate entities
The ability to change the color of an image
The ability to focus light on a specimen
How does wavelength affect the resolving power of a microscope?
Longer wavelengths increase resolution
Shorter wavelengths decrease resolution
Shorter wavelengths increase resolution (higher energy)
Wavelength has no effect on resolution
Which of the following are types of light microscopes?
Electron, Scanning Probe, Atomic Force, Bright-field, Fluorescence
X-ray, Infrared, Bright-field, Confocal, Dark-field
Bright-field, Phase-contrast, Differential Interference Contrast, Dark-field, Fluorescence, Confocal
Bright-field, Transmission Electron, Scanning Electron, Fluorescence, Confocal
What is the most common type of light microscope, which uses two lenses and is known as a compound microscope?
Dark-field microscope
Phase-contrast microscope
Bright-field microscope
Fluorescence microscope
What is the maximum magnification and resolution capability of a bright-field microscope?
1000X magnification; 0.5 µm resolution
2000X magnification; 0.2 µm resolution
1500X magnification; 0.3 µm resolution
2500X magnification; 0.1 µm resolution
What is the primary function of a phase-contrast microscope?
It uses fluorescence to highlight structures in a specimen
It enhances the difference in refractive index of the sample and its surrounding
It uses electron beams to create high-resolution images
It provides a three-dimensional view of the specimen
How does a specimen appear when viewed under a phase-contrast microscope?
Brighter than the surrounding
The same brightness as the surrounding
Darker than the surrounding
Fluorescent against a dark background
What is the key characteristic of a Differential Interference Contrast microscope?
It uses fluorescence to highlight specific structures in a specimen
Passes two beams (split light) through a specimen and then recombine out of phase
It uses electron beams to produce high-resolution images
It provides a dark background to enhance specimen visibility
How does a specimen appear when viewed under a Differential Interference Contrast microscope?
Fluorescent against a dark background
Darker than its surroundings
Colored with a 3D appearance
Transparent with no visible contrast
How does a Dark-Field Microscope create contrast?
It amplifies differences in refractive index
It passes light through a specimen at an angle so only refracted light enters the objective
It separates light into two beams and recombines them out of phase
 It uses a fluorescent tag to highlight the specimen
What is the function of a fluorescent tag in Fluorescence Microscopy?
It absorbs UV light and becomes transparent
It emits light of a specific wavelength when hit with UV light
It scatters visible light to increase contrast
It creates a three-dimensional colored image
What is a Fluorescence Microscope?
A microscope that uses angled light to create a dark background and bright specimen
A microscope that uses a fluorescent tag and UV light to make specific structures visible
A microscope that separates light into two beams to create a 3D image
A microscope that enhances contrast by amplifying differences in refractive index
What is the primary function of a Confocal Microscope?
To create a dark background while illuminating the specimen
To amplify differences in refractive index for contrast
To scan vertical sections of a specimen and reconstruct a 3D image
To use fluorescent tags to highlight specific structures
How does a Confocal Microscope achieve high-resolution imaging?
By using a special filter to capture specific wavelengths of light
By scanning vertical slices of a specimen with lasers and mirrors
By reflecting light off the specimen at an angle
By amplifying phase differences within the specimen
What role does the computer play in Confocal Microscopy?
It enhances magnification beyond 2000X
It reassembles scanned slices to create a 3D image (CAT scan for cells)
It filters out unwanted light to improve fluorescence visibility
It amplifies the brightness of the specimen against a dark background
Why does Electron Microscopy achieve much greater resolution than Light Microscopy?
It uses a fluorescent tag to highlight structures
Electrons have a much shorter wavelength than visible light
It amplifies differences in refractive index
It separates light into two beams and recombines them out of phase
What is the approximate resolving power of an Electron Microscope?
2 µm
2.5 nm
10 nm
1.5 µm
What is the maximum magnification of an Electron Microscope?
2,000X
10,000X
50,000X
100,000X
How does a Transmission Electron Microscope (TEM) create an image?
By passing electrons through a thin sample onto a fluorescent screen or photographic plate
By scanning the surface of a specimen with electron beams
By using phase shifts to enhance contrast
By separating light into two beams and recombining them out of phase
What is the magnification range of a TEM?
2,000X - 10,000X
10,000X - 100,000X
100X - 1,000X
500,000X - 1,000,000X
What type of image does an SEM produce?
A 1D internal structure image
A 3D surface detail image
A fluorescent-tagged image
A thin-section electron transmission image
Why is a specimen coated with heavy metal in SEM?
To make it fluorescent under UV light
To prevent artifacts from forming
To allow electrons to reflect back for imaging
To allow electrons to pass through the specimen
What is the primary advantage of Scanned-Probe Microscopy?
It can view live specimens at high resolution
It can resolve features 1/100 the size of an atom
It uses fluorescence to highlight specific molecules
It creates 3D images by reflecting electrons off a specimen
How does a Scanning Tunneling Microscope (STM) generate an image?
By passing electrons through a thin sample
By detecting the reflection of electrons from a surface
By scanning across a surface and creating a map
By using fluorescent dyes to label molecules
What is the difference between a Scanning Tunneling Microscope (STM) and an Atomic Force Microscope (AFM)?
STM creates a map, while AFM creates a 3D map
STM uses fluorescence, while AFM uses electron beams
STM only works with biological specimens, while AFM only works with metals
There is no difference; they are the same instrument
