Microcopes

Question 1

What are the magnifications and resolutions of a light microscope, TEM and SEM?

Answer 1

Light Microscope: x 1500, 0.2µm
TEM: x 500 000, 0.1 nm
SEM: x 100 000, 5.0 nm

Question 2

Light microscope description

Answer 2

Use light to form an image
You can see the nucleus
Not in perfect detail

Question 3

Advantage of light microscope

Answer 3

Cheaper
Easy to use
Small and light weight to use
Can observe living organism

Question 4

Disadvantages of light microscope

Answer 4

Can’t see sub-cellular structures of organelles
Not in colour
Only use thin specimen
Lower mag and res due to larger wavelength of light

Question 5

Description of TEM

Answer 5

Use electromagnets to focus a beam of electrons which is then transmitted through the specimen.
Denser parts of the specimen absorbed more electrons so makes it them look darker on the image

Question 6

Advantage of TEM

Answer 6

High resolution images
High quality and detailed images
High magnification
You can view internal structures of organelles

Question 7

Disadvantages of TEM

Answer 7

-Expensive,
-require training before use, -time consuming,
-thin layer of specimen, you have to use a vacuum so dead specimen only
-Images are black and white

Question 8

Description of SEM

Answer 8

Scan a beam of electron across the specimen to form an image. This makes the images you end up show on the surface of the specimen and can be 3D.

Question 9

Advantage of SEM

Answer 9

Thick specimen
3D images
Detailed images
Easy to operate

Question 10

Disadvantage of SEM

Answer 10

Lower resolution images than TEM
only use on dead specimen
Requires training
Time consuming
Can produce artefacts

Question 11

Microscope artefacts

Answer 11

They are things you see down the microscope that aren’t part of the cell or specimen that you’re looking at. Like dust air bubbles and fingerprints