Microscopy

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)

What is 1µm equivalent to in nm?

1µm = 1,000nm

What is a nanometer?

1 billionth of a meter (1m / 1,000,000,000) 10⁻⁹meter denoted by nm

What is a micrometer?

1 millionth of a meter (1m / 1,000,000) 10⁻⁶meter denoted by µm

What is a millimeter?

1 thousandth of a meter (1m / 1,000) 10⁻³meter denoted by mm

How many Viruses could fit into one Bacterium?

1,000 Viruses could fit into 1 Bacterium

What is 1 meter equivalent to in nanometers?

1m = 1,000,000,000nm

What is 1 meter equivalent to in micrometers?

1m = 1,000,000µm

What is 1 meter equivalent to in millimeters?

1m = 1,000mm

What is 1mm equivalent to in nm?

1mm = 1,000,000nm

What is 1mm equivalent to in µm?

1mm = 1,000µm

What size are Bacteria?

Bacteria are about 1µm or smaller 1 millionth of a meter 10⁻⁶meter

Give an example of a compound microscope.

Brightfield

What is the difference between brightfield and darkfield illumination?

Brightfield Illumination: Darkfield Illumination:

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

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

*Brightfield microscopy* Are cells live or dead? Are cells stained? How does the object and background appear?

Cells are either live and unstained or dead and stained. Dark objects are visible against a bright background.

*Darkfield microscopy* Are cells live or dead? Are cells stained? How does the object and background appear? What cell structures can be seen?

Cells are live No stain is used Light objects are visible against dark background-Can see cilia and flagella (signs of motility)

DIFFERENTIAL INTERFERENCE 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 Shows three dimensions Can see cilia and flagella (signs of motility) more clearly than darkfield or phase contrast Best resolution for live cells

*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

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

Are cells live or dead with a Transmission Electron Microscope?

Dead

What type of microscope is used to look at large objects?

Dissecting microscope

What are the different types of compound microscopes?

Light microscope and 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.

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

What is difference between regular microscopes and Transmission Electron Microscopes?

Transmission Electron Microscopes have a much higher resolution than regular microscopes.

What is Differential Interference Contrast used for?

Used for seeing organelles in live organisms in three dimensions

What is Phase Contrast Microscopy used for?

Used for seeing organelles in live organisms, 2D

What size are viruses?

Viruses are about 1nm 1 billionth of a meter 10⁻⁹meter

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.

When is a brightfield microscope used?

a. It is used for looking at live organisms with no stain. b. It can also be used for stained tissues.