Brainscape's Knowledge GenomeTM

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


See full index

Biology 2.1.1: Cell Structure > microscopy > Flashcards

microscopy Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

how does an optical microscope work?

A

light from a light source underneath the specimen passes through the specimen

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

what is the resolution of an optical microscope?

A

200nm

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

what is the magnification of an optical microscope?

A

x1500

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

what are the strengths of optical microscopes?

A
  • colour image
  • using live specimens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the weaknesses of optical microscopes?

A
  • poor resolution
  • 2D image
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what do optical microscopes allow us to see?

A

whole cells/tissues

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

how deos a transmission electron microscope work?

A

electrons are transmitted through a specimen and denser parts of the specimen absorb more electrons, becoming darker

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

what is the resolution of a TEM?

A

0.5nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the magnification of a TEM?

A

x1,000,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the strengths of TEMs?

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

what are the weaknesses of TEMs?

A
  • black and white image
  • 2D image
  • specimens must be dead
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what do TEMs allow us to see?

A

small organelles

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

how do scanning electron microscopes work?

A

electron beam is scanned across the specimen surface and electrons bounce off, gathering in a cathode ray tube

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

what is the resolution of SEMs?

A

2nm

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

what is the magnification of SEMs?

A

x500,000

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

what are the strengths of SEMs?

A
  • 3D image
17
Q

what are the weaknesses of SEMs?

A
  • black and white image
  • specimen must be dead
17
Q

what is the magnification calculation?

A

mag = image / actual

18
Q

what does magnification mean?

A

amount of times the image has been expanded than the object

19
Q

what does resolution mean?

A

the ability to distinguish between two objects

20
Q

which lens is the objective?

A

near to specimen

21
Q

which lens is the eyepiece?

A

used to view specimen

22
Q

why are there two lenses on a microscope?

A
  • improves magnification
  • reduces chromatic abreviation (diff colours traveling at diff speeds)
23
Q

why is resolution limited for optical microscopes?

A

light has a larger wavelength

24
Q

what is a dry mount?

A

a solid specimen viewed whole or sectioned on a slide under a cover slip

25
Q

what is a wet mount?

A

specimen suspended in liquid with a cover slip placed at an angle

26
Q

how is a squash slide prepared?

A
  • wet mount prepared
  • lens tissue used to press down cover slip
  • used for soft samples
27
Q

how is a smear slide prepared?

A
  • edge of slide used to smear a sample to create a thin coating
  • cover slip over top
28
Q

why should speciens on a slide be thin?

A

avoid air bubbles

29
Q

why is a stain sometimes used?

A

increase contrast to improve visibility

30
Q

what is differential staining?

A

distinguishes between two organisms/organelles
- positive dye attracts negative cytoplasm materials

31
Q

what is a gram stain?

A
  • separates pos/neg bacteria
  • crystal violet is applied to slide
  • iodine apllied to fix dye
  • washed with alcohol
32
Q

what is the acid fast technique?

A
  • differentiates mycobacterium
  • liquid solvent carries a dye into cells
  • mycobacterium not affected by acid alcohol cell wash absorbs dye
33
Q

how are mm converted into micrometres?

A

x1000

34
Q

how are micrometres converted to nm?

A

x1000

35
Q

how do you identify what is stained when using crystal violet and methylene blue?

A

negative organelles attract positive stain

36
Q

how do you identify what is stained when using nigrosin or methylene blue?

A

positive organelles attract negative stain

37
Q

how does a laser scanning confocal microscope work?

A
  • laser beam focuses on a small area on a sample surface
  • fluorophores in sample emit photons
  • photomultiplier tube amplifies signal onto a detector
  • image is produced in pixels
38
Q

how is the actual length of an image calculated using a stage micrometer?

A
  • line up eyepiece graticule with stage micrometer
  • count how many graticule divisions are in 100 micrometers
  • number of division / 100 = 1 division

Biology 2.1.1: Cell Structure (4 decks)

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