2.1.1 C) Use of Staining in Light Microscopy

Question 1

Stain:

Answer 1

coloured chemicals that bind to molecules in or on the specimen, making it easy to see

Question 2

Why are stains needed for some light microscope samples?

Answer 2

• in light microscopes the beam of light passes through the object being viewed
• an image is produced because some parts of the object absorb more light than others
• sometimes the object being viewed us completely transparent
• this makes the whole object appear white as light rays just pass straight through the object - staining can be used to get around this

Question 3

Use of differential staining:

Answer 3

to identify different cellular components and cell types

Question 4

How does differential staining work?

Answer 4

• some stains bind to specific structures, staining each structure differently so they can be easily seen
• stain can also be taken up by some pats of an object more than others → contrast between heavily stained and lightly stained means that the different parts of cell can be seen

Question 5

Uses of staining:

Answer 5

1. Makes objects visible in light microscopes
2. Increases contrast so that the object can be seen more clearly
3. Is often specific to certain tissues or organelles