Slides and Photomicrographs

Question 1

What are ‘stains’?

Answer 1

They are coloured chemicals that bind to molecules In or on the specimen, making the specimen easier to see

Question 2

Explain what differential staining is

Answer 2

When some stains bind to specific cellular structures to stain each structure differently and can be identified within a single preparation

Question 3

Name an all purpose stain

Answer 3

Methylene Blue

Question 4

Describe four examples of how differential staining can be utilised

Answer 4

Eosin stains cytoplasm
Sudan red stains lipids
Acetic Orcein binds to DNA and stains chromosomes dark red
Iodine in potassium iodine solution stains cellulose yellow and starch granules blue or black

Question 5

Explain how experts make ‘prepared and permanently fixed slides’

Answer 5

Dehydrating the specimen
Embedding them in wax to prevent distortion during slicing
Make sections that are stained and mounted in a special preserving chemical

Question 6

What is the equation involving A M I?

Answer 6

M = I/A
magnification = image size / actual size

Question 7

List the types of specimen that can be viewed using optical microscopes

Answer 7

Living organisms e.g. Amoeba
Smear preparations of human blood and cheek cells
Thin plant/animal/fungal tissue sections