Slide prep and stains

Question 1

when preparing a slide for a light microscope why do we use a stain?

Answer 1

• coloured stains bind to chemicals in or on specimen which allows specimen to become visible (certain organelle).

•improves contrast

Question 2

What is methylene blue used for?

Answer 2

•all purpose staining

Question 3

what do acetic stains stain?

what colour?

Answer 3

•DNA
•dark red

Question 4

what does eosin stains stain?

what colour?

Answer 4

-Cytoplasm
-Pink

Question 5

What does sudden red stain?

what colour

Answer 5

-lipids
-reddish brown

Question 6

what does iodine stain?

what colour?

Answer 6

-starch : blue/black
-cellulose in plant cells yellow

Question 7

what must the specimen be like when preparing for light microscope?

Answer 7

-thin sections to allow light to pass through
-artefacts may occur (damage to specimen during prep)

Question 8

what are the different methods of preparing a slide?

explain them

Answer 8

1) Dry mounts - specimen viewed with just coverslip on top e.g hair, plant tissue
2) Wet mounts - water added or stain before lowering coverslip at angle to reduce air bubbles e.g aquatic organisms
3) Squash slides - like wet mounts but push coverslip to squash to specimen e.g root tip squash
4) Smear slides - using edge of another slide to smear sample across slide, coverslip on top e.g blood cells in blood sample