Flashcards
Types of slides and staining
Cards in this deck (22)
- 1Dry mountSolid specimen
Viewed whole or in thin sections
Specimen placed in centre of slide and covered with cover slip - 2Wet mountSpecimen suspended in liquid (water/immersion oil)
Cover slip placed on top from angle - 3Squash slidesWet mount prepared first
Lens tissue used to gently press down cover slip
Care taken not to break cover slip when squashed - 4Smear slidesEdge of slide smears sample
Thin even coating on slide
Cover slip placed over slide - 5What things used dry mount?Hair
Pollen
Dust
Insect parts
Muscle tissue
Plants - 6What things used wet mount?Aquatic samples
Other living organisms - 7What things use squash slides?Root tips
Soft samples - 8What uses smear slides?Blood
- 9Why is staining done?Cytosol of cells and cell structures are often transparent
Increases the contrast between structures - 10What are the preparation steps of staining?Sample placed on slide and air dried
Heat fixed by passing through a flame
Adheres to microscope slide
Takes up the stain - 11What does crystal violet/methylene blue stain?Both positively charged dyes
Attracted to negative substances in cytoplasm
Stains cell components - 12What does nigrosin/congo red stain?Negatively charged
Stays outside the cell (repelled by negative cytoplasm)
Stains the background
Cell stands out against the background - 13What technique does nigrosin/congo red stain use?Negative stain technique
- 14What is differential staining?Distinguishes between 2 types of organisms/organelles that would be hard to identify
- 15What is gram stain technique used to do?Differentiate between gram positive bacteria and gram negative bacteria
- 16What are the first 3 steps of gram stain technique?1. Crystal violet stain applied
2. Iodine added to fix dye
3. Slide washed with alcohol - 17What is shown after the first 3 steps?Gram positive - retain stain and appear blue/purple
Gram negative - thinner walls, loose stain - 18What are stages 4 and 5 of gram stain technique?4. Stained with sofranin dye (counterstain)
5. Bacteria appear red - 19What is shown at the end of gram stain technique?Gram positive - Susceptible to penicillin which inhibits form of cell walls
Gram negative - Thinner walls aren't susceptible to penicillin - 20What is acid fast technique used for?Differentiate between Mycobacterium and other types of bacteria
- 21What are the steps of acid fast technique?Lipid solvent carries carbolfuchsin die into cells
Cells washed with dilute acid-alcohol solution
Mycobacterium retain carbofulchsin dye(red)
Other bacteria loose stain and exposed to methylene blue - 22General stages of slide preparationFixing
Sectioning - dehydrated,wax,sliced with microtome
Staining
Mounting - on slide and cover slip on top
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- AS level Biology (Chapter 02 - Microscopy) Flashcards on Types of slides and staining, created by Bethany Westwood on 25/09/2016.
- Created by
- Bethany Westwood · Sep 2016
- Updated
- Jan 30, 2017
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