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Biology module 2 > Microscopes > Flashcards

Flashcards in Microscopes Deck (27)
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1
Q

Magnification of light

A

X1500

2
Q

Resolution of light

A

200nm

3
Q

Magnification of laser scanning confocal

A

X2000

4
Q

Resolution of laser scanning confocal

A

50nm

5
Q

Magnification of transmission electron

A

X500,000

6
Q

Resolution of transmission electron

A

0.2nm

7
Q

Magnification of scanning electron

A

X100,000

8
Q

Resolution of scanning electron

A

2nm

9
Q

Difference between transmission and scanning electron

A

Transmission=better resolution

Scanning=3D

10
Q

Why they have different resolutions

A

Different wavelengths.

Smaller wavelength=better resolution

11
Q

Definition of magnification

A

How much an image has been enlarged by compared to the object

12
Q

Definition of resolution

A

The minimum distance two points can be distinguished

13
Q

Definition of staining

A

Using stains to create contrast between things and so they stand out against the background.

14
Q

m->mm->um->nm

A

X1000

15
Q

Magnification triangle

A

Image size

A sizeXmagnification

16
Q

What are the advantages of using a light microscope?

A

They are the cheapest
Easy to use
Can be used for dead and living samples
Relatively easy to section/stain specimens

17
Q

Why is it important to cut sections thinly when viewing under a microscope?

A

Light needs to be able to pass through the specimen

Clarity - you want to only be able to see a single layer of cells.

18
Q

What 2 pieces of equipment are used to measure the actual length of an object under magnification?

A

Eyepiece graticule

Stage micrometer

19
Q

What is differential staining?

A

Different parts of a cell/different cell types are stained with different things so they can be distinguished.
Some stains bind to specific structures within a cell so they can be easily picked out on a specimen.

20
Q

What are light microscopes used to observe?

A

Whole cells and tissues

21
Q

What are transmission electron microscopes used to observe?

A

Organelles

22
Q

What are laser scanning confocal microscopes used to observe?

A

Cell surfaces

23
Q

How do you measure the diameter of a structure on a microscope picture?

A

Use eyepiece graticule/stage micrometer
Align stage micrometer to eyepiece graticule
Calibrate length of each division of eyepiece graticule in um
Replace stage micrometer with slide and measure number of eyepiece divisions to determine size

24
Q

What are the differences between optical and electron microscopes?

A

Optical uses light, can look at living samples, has a low resolution/magnification and can distinguish colour
Electron is opposite

25
Q

What 2 stages are there to prepare a large tissue specimen for light microscopy?

A

Sectioning

Staining

26
Q

Why do most specimens need to be stained?

A

Many cells are colourless so detail wouldn’t be seen

27
Q

How do laser scanning confocal microscopes produce an image?

A

Specimen is dyed and lasers are used to cause fluorescence of the specimen
This allows depth selection through a thick specimen to construct a 3D model with high resolution