what is a basic stain?
+ charged dyes
stain bacterial cells (have a negative charge)
DO NOT STAIN SLIDE (has a positive charge)
what is an acidic stain?
- charged dyes
stain slide/background (has + charge)
DO NOT STAIN BACTERIAL CELLS (has - charge)
what are some characteristics of simple staining?
- use only one dye
- all cells stain color of chosen dye
- determines cell size, morphology, and arrangement
- typical stains used
methylene blue
crystal violet
safranin
what do simple stains tells us?
size
shape
arrangement
how many and what are the arrangements of coccus?
5 circular
1. diplococci (Cocci that remain in pairs after dividing are called diplococci)
- streptococci (Cocci that remain in chains after dividing are called streptococci)
- tetrad (Cocci that divide in two planes and remain in groups of four are called tetrads)
- Sarcinae (Cocci that divide in three planes and remain in groups cube like groups of eight are called sarcinae)
- Staphylococci (Cocci that divide in multiple planes and form grape like clusters or sheets are called staphylococci)
how many and what are the arrangements bacillus?
4 rod
- single bacillus (Most bacilli appear as single rods)
- Diplobacilli (appear in pairs after division.)
- Streptobacilli (appar in chains after division)
- Coccobacillus (Some bacilli are so short and fat that they look like cocci and are referred to as coccobacilli)
how many and what are the arrangements of spirilla?
3 (have one or more twists)
- Vibrio (looks like a coma)
- Spirillum (one curve)
- Spirochete (many curves)
what are some other shapes of bacteria?
star shaped
rectangle shape
what does washing a slide with soap and water do?
removes oil and grease
why should one flame a slide after washing it?
removes any remaining oil and oil from handling
why should one use a small drop of water and small amount of bacteria?
enable smear to dry with in a few minutes
see single layer of cell (tiny amount of bacteria)
why is it necessary to heat fix?
- allow cells to adhere to slide
- kill bacteria
- coagulate cytoplasmic proteins (make them more visible)
what do we dry the slide with?
bibulous paper
what is a chromogen?
colored molecule
what is a chromophore?
portion of chromogen that gives it its color
a chromogen can have multiple chromophores
what is the auxochrome?
charged portion of chromogen and allows it to act as a dye
