Staining & Calibrating

Question 1

What stains are used for light microscopes?

Answer 1

Dyes, such as eosin and methylene blue

Question 2

How does staining work in a light microscope?

Answer 2

The stain is taken up by some parts of the object more than others and the contrast makes different parts show up

Question 3

What are different stains used for?

Answer 3

To make different things show up, such as eosin to stain cytoplasms and methylene blue for DNA so multiple stains can be used at once

Question 4

What stains are used in electron microscopes?

Answer 4

Objects are dipped into heavy metals, such as lead

Question 5

How does staining work in electron microscopes?

Answer 5

The metal ions scatter the electrons again creating contrast so some parts show up darker than others

Question 6

What is a stage micrometer?

Answer 6

It is placed on the stage and is a slide with an accurate scale used to work out the value of the divisions on the eyepiece graticule

Question 7

What is an eyepiece graticule?

Answer 7

It is fitted onto the eyepiece and acts as a transparent ruler with numbers but no units

Question 8

How you calculate the field of view?

Answer 8

1. Count how many eyepiece units equal 100 stage units
2. Multiply the number of stage units by the magnification of both the eyepiece land the lens
3. Divide this number by the number of eyepiece units