Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOL 221 > Microscopy > Flashcards

Microscopy Flashcards

1
Q

What size does an object have to be in order to be visualized?

A

1/2 the wavelength of the electromagnetic radiation being shown on it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is resolution?

A

resolution refers to the ability to distinguish two points from each other. Smaller resolution = better

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the wavelength of a light microscope?

A

0.2 um

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the wavelength of electron microscopy?

A

2 nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How can you improve resolution?

A
  1. change the illumination source (electrons)
  2. increase the intensity of the illumination
  3. replace the medium light travel through (prevent refraction)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What oil is used for 100x objective?

A

immersion oil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is contrast?

A

how distinct is the specimen from the background

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How can you improve contrast?

A
  1. Positive stain (specimen)
  2. Negative stain (background)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the different types of light microscopy?

A
  1. Bright field
  2. Darkfield
  3. phase contrast
  4. Interference
  5. Fluorescence
  6. “Superresolution” fluorescence
  7. Confocal scanning laser
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does brightfield work?

A

Uses light, diaphragm, and condenser to condense light through slide.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does darkfield work?

A

Uses a special type of condenser to bend light away from objective. If light hits specimen, it will be bent up into lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is phase contrast?

A

Uses phase-shifting of refracted light (caused by photon drag) to enhance contrast. refractive index differences are amplified

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is interference microscope?

A

uses 2 beams of 90 degree polarized light to detect 3D details in the sample. light is separated by prism and recombine after specimen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is fluorescence microscope?

A

Uses excitation wavelength as illumination light, can see emission wavelength of fluorescently-labeled specimen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are fluorophores?

A

chemicals that emit visible light when they are illuminated by a shorter wavelength of light (usually UV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is superresolution fluorescence?

A

uses very brief excitation of low-intensity fluorophore stain, followed by computer averaging, to enhance resolution of light microscope

17
Q

Can you use multiple fluorophores?

A

Yes, they are linked to different antibodies

18
Q

What is confocal scanning laser microscope?

A

uses an aperture to shut out light from all but one focal plane of the object. Computer builds up 3-d object plane by plane

19
Q

Types of electron microscopy?

A
  1. TEM
  2. SEM
  3. electron cyrotomography
20
Q

What is TEM?

A

transmission electron microscopy; electron beam passes through the specimen, just like a beam of light. uses dye that absorbs electrons

21
Q

What is SEM?

A

Scanning electron microscopy; detects electrons and x-rays scattered from a surface, dramatic 3D views

22
Q

What is electron cryotomography?

A

rotate object; capture images at different angles. use software to compile a 3d shape

23
Q

What is atomic force microscopy?

A

electric field is monitored at the tip of a nanotube probe. Field varies as probe is pushed over a surface. Can see atoms

24
Q

What is a simple stain?

A

shows outline of bacteria; basic (+) dye attaches to (-) phospholipid head groups?

25
Q

What is differential stain?

A

more than one stain is used - cell stain differently based on call properties. Includes gram stain and acid-fast stain

26
Q

What is a gram stain?

A

shows thickness of peptidoglycan; more than one stain is used

27
Q

What are gram stain results?

A

pink = thin (gram -)
purple = thick (gram +)

28
Q

What is acid-fast stain?

A

used for bacteria with waxy cell walls; differentiates based on waxy coating impervious to acidified alcohol

29
Q

What are acid-fast stain results?

A

red = acid-fast (waxy)
blue = not

30
Q

What is negative stain?

A

stains the background, not the cell

BIOL 221 (32 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions