🧪 Micro lab #3

What is a smear ?

a layer of cells that are stuck on the surface of slide w/out changing the morphology

What is staning?

adding color to bacteria to help view it

What are the 2 types of stain you can perform? describe them

Basic dye: direct stain (bacteria gets stained)
Acidic dye: indirect stain (background gets stained)

In an acid dye the dye remains in the ___ of the cell and in a Basic dye the dye remains it in the ___ of the cell

outside
indise

What is a negative stain?

(indirect stain) stains the background

What are the 2 types of differential stains? describe them

gram stains gram +/- and gram variable
Acid fast stain: acid fast/ non acid

What is a special (structural) stain? What structures in specific can you view?

stain that helps identify external/internal structures,
Endospores, capsules, flagella

What kind of stain is this ?

endospore stain

what kind of stain is this ?

flagella

What kind of stain is this ?

capsule

What kind of dyes do you use for the following ?
Bacillus Megaterium
Staphylococcus Epidermis
E.coli

Methylene blue
Safranin
Crystal violet

What kind of dye does a negative stain use ?

acidic dye (nigrosin) to stain the background

Why do we perform a negative stain?

make a halo around bacteria to determine morphology/capsules

WHat is the difference between gram + and gram - ? what color are they ?

gram += keep their primary dye (purple)
gram - = dont keep primary dye (pink)

fill the following by their proper gram/color/shape

cocci,cocci,Rod,rod,rod
p,p,p,pink,pink
+,+,+,-,-

What dye do we use from the gram staining?

Crystal violet, Iodine, 95% ethanol, safranin

In an acid fast stain the cells have a cell wall with high % of____retains dye when decolonized

mycolic acid

Describe Endospore

resting structure resist harsh enviroment

What are the different types of endopspiores?

Central
Subterminal
Terminal

What dye do we use for Endospore stain ?

malachite green, safranin

what kind of dye do we use for acid fast stain ?

methylene blue,

Describe a capsule (3)

sugar coat of bacteria that cant be stain and is important for virulence

How can you view a capsule ? what dye do you use ?

negative stain
nigrosin, congo red

What is flagella used for ?

movement

After what step in the gram stanining will the cells change color ?

decolorizing : gram+: pruple, gram -:colorless until safranin