2.2.1 Microscopes

Question 1

What are some advantages of light microscopes

Answer 1

• Cheap
• Easy to use
• Portable
• Can view living species

Question 2

What cannot be observed with a light microscope?

Answer 2

Non membrane bound cells eg.ribosomes

Question 3

What are some disadvantages with Laser Scanning Microscopes

Answer 3

• Expensive
• Not portable

Question 4

What are Laser Scanning Microscopes used to observe?

Answer 4

Living specimens as well as cells

Question 5

What is the magnification in light microscopes?

Answer 5

x1500 or in some x2000

Question 6

What is the resolution in light microscopes?

Answer 6

200nm

Question 7

Does Laser Scanning Microscopes have high or low resolution?

Answer 7

High

Question 7

Does Laser Scanning Microscopes have high or low resolution?

Answer 7

High

Question 8

What is the magnification is Transmission Electron Microscope?

Answer 8

x2,000,000

Question 9

What is the resolution in Transmission Electron Microscope?

Answer 9

0.2nm

Question 10

What is an advantage of Transmission Electron Microscope?

Answer 10

A very high magnification

Question 11

What are some disadvantages with Transmission Electron Microscopes?

Answer 11

• Black and white image produced
• Specimen has to be dead

Question 12

How does Electron Transmission Microscope work?

Answer 12

• Specimen chemically fixed by being dehydrated and stained (stained with metal salts)
• Beam of electrons pass through specimen
  -2D black and white image produced

Question 13

What are some differences between the images produced with Transmission Electron Microscope compared to Scanning Electron Microscope?

Answer 13

TEM - 2D black and white image produced
SEM - 3D coloured image can be produced

Question 14

What is the magnification for Scanning Electron Microscopes?

Answer 14

x15 to x200,000

Question 15

What is the resolution for SEM?

Answer 15

3nm to 20nm

Question 16

What are some advantages of SEM?

Answer 16

• Can create a 3D image
• Colour can be added to image through computer software programmes

Question 17

What are some disadvantages of SEM?

Answer 17

• Very large so is not portable
• Very expensive
• Needs a lot of skill and training to use

Question 18

Definition for electron microscope

Answer 18

photograph of an image seen using an electron microscope

Question 19

Definition of magnification

Answer 19

The number of times larger an image appears, compared with the size of the object

Question 20

Definition of organelles

Answer 20

Small structures within cells, each of which has a special function

Question 21

Definition of photomicrograph?

Answer 21

Photograph of an image seen using an optical microscope

Question 22

Definition of resolution

Answer 22

The clarity of an image, the higher the resolution the clearer the image