2.1, 2.2, 2.3: Microscope Types

Question 1

Describe the advantages of Light Microscopes

Answer 1

• Cheap, easily accessible, easy to use
• Natural colour of material can be observed
• Living organisms can be observed
• Preparation is quick and simple

Question 2

Describe the disadvantages of Light Microscopes

Answer 2

• Low resolution
• Low magnification compared to other microscopes

Question 3

Describe the advantages of Electron Microscopes in general

Answer 3

• Can see detail of organelles
• Better resolution and magnification than light microscopes

Question 4

Describe the disadvantages of Electron Microscopes in general

Answer 4

• No colour
• Very large and must be operated in special rooms
• Expensive
• Damages the specimen
• Preparation of material is lengthy and complex.

Question 5

Describe how a Transmission Electron Microscope works, and what type of image it produces

Answer 5

Fires a beam of electrons though the specimen and produces a 2D image

Question 6

Describe how a Scanning Electron Microscope works and what type of image it produces

Answer 6

Fires a bean of electrons across the surface of a specimen and produces a 3D image.

Question 7

Why do specimens need to be treated in very specific ways for Electron Microscope scanning?

Answer 7

Because the inside of an electron microscope is a vacuum.

Question 8

For transmission electron microscopy, what has to be done to the sample?

Answer 8

Must be dehydrated, set in resin and stained

Question 9

For scanning electron microscopy, what has to be done to the sample?

Answer 9

Has to be dehydrated, and coated with heavy metals.

Question 10

What is a graticule?

Answer 10

A specialised piece of glass inserted into the microscope, that features a calibrated grid or scale etched into its surface

Question 11

What are the two types of graticules?

Answer 11

Eyepiece graticule and stage graticule

Question 12

What is 1 stage micrometer unit equal to?

Answer 12

10 micrometers

Question 13

What are the names of the two lenses in a compound light microscope?

Answer 13

Eyepiece lens and objective lens.

Question 14

Which has greater resolution, TEM or SEM?

Answer 14

TEM

Question 15

Which has greater magnification, TEM or SEM?

Answer 15

TEM