Microscopy Flashcards
What is a millimeter?
1 thousandth of a meter (1m / 1,000)
10-3meter
denoted by mm
What is a micrometer?
1 millionth of a meter (1m / 1,000,000)
10-6meter
denoted by µm
What is a nanometer?
1 billionth of a meter (1m / 1,000,000,000)
10-9meter
denoted by nm
What is 1 meter equivalent to in millimeters?
1m = 1,000mm
What is 1 meter equivalent to in micrometers?
1m = 1,000,000µm
What is 1 meter equivalent to in nanometers?
1m = 1,000,000,000nm
What is 1mm equivalent to in µm ?
1mm = 1,000µm
What is 1mm equivalent to in nm ?
1mm = 1,000,000nm
What size are Bacteria?
Bacteria are about 1µm or smaller
1 millionth of a meter
10-6meter
What size are viruses?
Viruses are about 1nm
1 billionth of a meter
10-9meter
How many Viruses could fit into one Bacterium?
1,000 Viruses could fit into 1 Bacterium
What are the two commonly used types of microscopes?
Simple and Compound
How many lenses does each microscope have?
Simple has one (ocular)
Compound has one or more (ocular plus objective)
Give an example of a compound microscope.
Brightfield
What are the different types of compound microscopes?
Light microscope and Electron microscope
What type of microscope is used to look at large objects?
Dissecting microscope
When is a brightfield microscope used? x2
a. It is used for looking at live organisms with no stain.
b. It can also be used for stained tissues.
When is darkfield illumination needed?
a. It is used for live organisms with no stain.
b. It is also used to look at fluorescent organisms.
What is the difference between brightfield and darkfield illumination?
Brightfield Illumination:

Darkfield Illumination:
What is Phase Contrast Microscopy used for?
Used for seeing organelles in live organisms, 2D
What is Differential Interference Contrast used for?
Used for seeing organelles in live organisms in three dimensions
- Describe Fluorescence Microscopy
Cells are stained with fluorescent dyes (called fluorochromes). UV Light is shined on the specimen. Fluorescent substances absorb UV light and emit visible light
What is difference between regular microscopes and Transmission Electron Microscopes?
Transmission Electron Microscopes have a much higher resolution than regular microscopes.
Are cells live or dead with a Transmission Electron Microscope?
You can only view dead cells under the transmission electron microscope.
What is the difference between a Scanning Electron Microscope and a transmission electron microscope?
Scanning Electron Microscope has a very high resolution like a transmission electron microscope except it makes images in three dimensions.
What happens in a Scanning Probe Microscope and how does it affect the color?
Scanning Probe Microscope passes a scan over the specimen, line by line. The surface dimensions are recorded and sent to a computer, which shows the image in false color.
Brightfield microscopy:
Are cells live or dead?
Are cells stained?
How does the object and background appear?
Brightfield-
Cells are either live and unstained or dead and stained.
Dark objects are visible against a bright background.
Phase-Contrast Are cells live or dead? Are cells stained? Are images three dimensional? What cell structures can be seen?
Cells are live
No stain is used
Not three-dimensional
Can see cilia and flagella (signs of motility) more clearly than darkfield
DIFFERENTIAL INTERFERENCE CONTRAST Are cells live or dead? Are cells stained? Are images three dimensional? What cell structures can be seen? How is resolution?
Cells are live No stain is used Shows three dimensions Can see cilia and flagella (signs of motility) more clearly than darkfield or phase contrast Best resolution for live cells
FLUORESCENCE
Are cells live or dead?
Are cells stained?
When is this used?
Cells are dead
Stain is fluorescent dye- creates visible light
Quick dx of TB & Syphilis
TRANSMISSION ELECTRON Are cells live or dead? Are cells stained? Are images three dimensional? What cell structures can be seen? How is resolution?
Cells are dead Stain with heavy metal salts is used Images are not 3D Can see organelles in cells Best resolution of all microscopes
SCANNING ELECTRON
Are cells live or dead?
Are images three dimensional?
What structures can be seen?
Cells are dead
Images are 3D
Surface view only
SCANNING PROBE
Describe how it works
What are 2 drawbacks?
Specimen is scanned, image is sent to computer-Drawback: Slower in acquiring images
Drawback: Max image size is smaller
Darkfiled Microscopy are cells live or dead are cells stained how does the object and background appear what cell structure can be seen
cells are live
no stain
light objects are visible against dark background
can see cilia and flagella (signs of motility)
