Microscopes

Question 1

Magnification of light

Answer 1

X1500

Question 2

Resolution of light

Answer 2

200nm

Question 3

Magnification of laser scanning confocal

Answer 3

X2000

Question 4

Resolution of laser scanning confocal

Answer 4

50nm

Question 5

Magnification of transmission electron

Answer 5

X500,000

Question 6

Resolution of transmission electron

Answer 6

0.2nm

Question 7

Magnification of scanning electron

Answer 7

X100,000

Question 8

Resolution of scanning electron

Answer 8

2nm

Question 9

Difference between transmission and scanning electron

Answer 9

Transmission=better resolution

Scanning=3D

Question 10

Why they have different resolutions

Answer 10

Different wavelengths.

Smaller wavelength=better resolution

Question 11

Definition of magnification

Answer 11

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

Question 12

Definition of resolution

Answer 12

The minimum distance two points can be distinguished

Question 13

Definition of staining

Answer 13

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

Question 14

m->mm->um->nm

Answer 14

X1000

Question 15

Magnification triangle

Answer 15

Image size

A sizeXmagnification

Question 16

What are the advantages of using a light microscope?

Answer 16

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

Question 17

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

Answer 17

Light needs to be able to pass through the specimen

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

Question 18

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

Answer 18

Eyepiece graticule

Stage micrometer

Question 19

What is differential staining?

Answer 19

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.

Question 20

What are light microscopes used to observe?

Answer 20

Whole cells and tissues

Question 21

What are transmission electron microscopes used to observe?

Answer 21

Organelles

Question 22

What are laser scanning confocal microscopes used to observe?

Answer 22

Cell surfaces

Question 23

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

Answer 23

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

Question 24

What are the differences between optical and electron microscopes?

Answer 24

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

Question 25

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

Answer 25

Sectioning

Staining

Question 26

Why do most specimens need to be stained?

Answer 26

Many cells are colourless so detail wouldn’t be seen

Question 27

How do laser scanning confocal microscopes produce an image?

Answer 27

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