Cells

Question 1

What is magnification?

Answer 1

How much bigger a sample appears to be under a microscope than it is in real life

Question 2

What is resolution?

Answer 2

The ability to distinguish between 2 points on an image - amount of detail

Question 3

How to calculate total magnification?

Answer 3

Objective x Eyepiece

Question 4

Describe a light microscope

Answer 4

Samples are generally dead
Very thin sample slices are needed
Sample may be stained to see important features (iodine, methylene blue, orcein)
Image is 2D

Question 5

Describe an electron microscope

Answer 5

Sample is dead
Sometimes thinly sliced
Coated in chemicals or gold
Samples are placed in a vacuum
Photomicrographs are 3D

Question 6

What are the 2 types of electron microscopes

Answer 6

Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM)

Question 7

Describe a transmission electron microscope

Answer 7

Electron beam passes through a thin sample
Electrons pass through the denser parts easily (contrast)
Image is 2D
Magnification is x 500,000

Question 8

Describe a scanning electron microscope

Answer 8

Electrons don’t pass through the specimen (bounce off the specimen)
3D view
Magnification is x 100,000

Question 9

What are the advantages of an electron microscope?

Answer 9

Resolution is 0.1mm, detailed images or organelles,
3D images shows contours (SEM)

Question 10

What are the disadvantages of an electron microscope

Answer 10

Electron beams deflected by air molecules - vacuum needed
Expensive, skill + training needed