Microscopy

Question 1

Magnification

Answer 1

How many times bigger the image is then the actual object

Question 2

Resolution

Answer 2

Minimum distance apart two objects can be in order to appear as separate items
The shorter the wavelength the greater resolution
Greater resolution means a clearer image

Question 3

Light microscope

Answer 3

Beam of light is shore through the specimen
Poor resolution
Little intracellular detail can be seen

Question 4

Why do specimens need to be thin in a light microscope?

Answer 4

For light to pass through the specimen and so that you only focus on one layer of the cell

Question 5

Why would sections of specimens need to be stained in a light microscope?

Answer 5

Thin sections are transparent
Selectively stain cell components to be able to see them

Question 6

Electron microscope

Answer 6

Beam of electrons
Shorter wavelength and higher resolution
Becomes are focused using electromagnets as electrons are negatively charged
Requires training

Question 7

Transmission electron microscope
TEM

Answer 7

Ultra thin sections stained containing heavy metals
Electron beam on specimen producing an image on the screen
Living specimens cannot be observed
2-d image in black and white

Question 8

Scanning electron microscope
SEM

Answer 8

Electrons do not penetrate the specimen
Electrons are scattered depending on the contours on the surface of the specimen
3-d image in black and white colour is added by computer program
Resolution is lower than TEM but better than light microscope

Question 9

Artefacts

Answer 9

Images may contain artefacts
Can appear as breaks in membranes, empty spaces in cells and granular deposits