Introduction to Microscopy Flashcards

1
Q

In what two ways to light microscopy and electron microscopy differ?

A
  1. Optical resolution
  2. Available magnification
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2
Q

Light microscopy and electron microscopy differ in ______________ _____________ and ____________ ___________.

A

Optical resolution

Available magnification

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3
Q

What does “resolution” mean in practical terms?

A

The capacity of an optical system to reveal detail in a specimen

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4
Q

What is the optical resolution of a typical light microscope?

A

0.2 µm

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5
Q

What’s the optical resolution of an average electron microscope?

A

1 nm

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6
Q

What is the available magnification of an average light microscope?

A

1000X

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7
Q

What is the available magnification in an average electron microscope?

A

100,000X

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8
Q

What are the two types of electron microscopes?

A
  1. Transmission
  2. Scanning
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9
Q

_______________ EM produces three-dimensional images, but these are restricted to the surface of the object with the internal structure concealed from view.

A

Scanning

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10
Q

__________________ EM is so named be ause the electron beam must pass through the specimen, which has been cut into ultrathin sections, resulting in a two-dimensional image of section planes.

A

Transmission

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11
Q

Which electron microscopy is more informative? Transmission or scanning?

A

Transmission

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12
Q

What is the available area with which one can view under a light microscope?

A

Several cm2

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13
Q

What is the available area with which an electron microscope can provide?

A

Less than 1 mm2

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14
Q

What are three ways in which electron microscopy is less flexible than light microscopy?

A
  1. The available area is generally less than one square mm
  2. Few staining methods are available, producing only black and white images
  3. Costly and time-consuming, thus not available to most students
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15
Q

Electron-dense describese the relative ________________ of an image of a transmission EM.

A

Darkness

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16
Q

Electron-lucent describes the relative _______________ of an image in electron microscopy.

A

Lightness

17
Q

One major group of specific methods known as ________________ techniques employes reagents known to react with defined cellular constituents (e.g., lipids, glycogen and DNA), thereby producing selective coloration recognizable by light microscopy.

A

Histochemical

18
Q

In a subset known as _______________ histochemistry, the activity of ________________ can similarly be demonstrated by staining for their specific substrates or end products.

A

Enzyme

Enzymes

19
Q

_____________________ is immunologically based in which antibodies are raised against specific cellular components (i.e., antigens) and then conjugated with a visual marker appropriate for LM or EM.

A

Immunohistochemistry

20
Q

What is a problem common to both light and electron microscopy?

A

The need to prevent autolytic degeneration and to preserve cellular ultrastructure

21
Q

_________________ causes cross-linking of macromolecules, which reduces and arrests biological activity, at the same time rendering the cells more amenable to staining.

A

Fixation

22
Q

Fixatives such as ______________ and __________________ are used to prevent autolytic degeneration and to preserve cellular ultrastructure.

A

Formaldehyde

Glutaraldehyde

23
Q

Most tissues are too thick to be examined directly in the microscope and thus must be _____________ into thin slices. To faciliate cutting of these thin slices, the tissue is usually ______________ in a hard medium like parrafin wax or plastic resin. Fixed tissues generally require _______________ with organic solvents before this step.

A

Sectioned

Embedded

Dehydrated

24
Q

What are artefacts?

A

Distortions in cell and tissue architecture

25
Q

What types of light microscopy have been developed to monitor living tissue cultures?

A

Phase contrast

Interference contrast

Confocal microscopy