Gram staining

Question 1

simple stain

Answer 1

-all cells on slide will stain same colour
-methylene blue, CV, Safranin

Question 2

differential stain

Answer 2

-different cell types or cellular components stain differently
-used to examine different types of cells in a mixture and for dientifyin individual organisms based on their structure

Question 3

what makes the gram pos stain priple

Answer 3

-CV sticks to thicker cells wall and not decolourized by ethanol

Question 4

acid fast stain

Answer 4

-gram nuetral
-mycolic acids
-carbol fusion penetrates the cell wall and it cannot be removed with organic solvents = acid fast
-non acid fast bacteria will lose this red colour when washed with acid/alcohol and become colourless

Question 5

schauffer fulton stain

Answer 5

-endospore
-malachite green forced into the spore by steam
-mother cells do not contain greend ye but the endospores do
-mother cells readily decolourized with water

Question 6

flagella stain

Answer 6

-deposition stain
-stain precipitate around flagellum increases apparent diameter and making it visible under the light microscope

Question 7

capsule stain

Answer 7

-staining the bacteri abackground more intensly than the capsule itself
-the capsule stain technique stains the area around the capsule with negative acidic stain then a basic stain will colourize the cell itself
-the capsule appeares as a white halo between the cell and the darker background

Question 8

crystal violet

Answer 8

-primary stain
-applied first

Question 9

iodine

Answer 9

-mordant
-ion that binds to stain to fix it in place
-iodine complexes with CV, precipitating it from solution and attaching it to the cell membrane
-fixing the dye
-all cells purple

Question 10

95% ethanol

Answer 10

-decolourizing agent
-protein dehydrating agens and lipid solvent to remove CV
-ethanol dehydrates and shrinks peptidoglycan on the surface of cell membrane trapping the CV-iodine complex on the surface of the cell membrane
-in gram neg- ethanol dissolves the lipids in the outer membrane releaseing the primary stain from the cell

Question 11

safranin

Answer 11

-a counterstain
-stains any cells that were decolurized by ethanol

Question 12

steps of slide prep

Answer 12

-drop of distilled water
-add small amount of bacteria - no turbidity
-heat fix

Question 13

staining procedure

Answer 13

-gloves
-1-2 drops of CV for 1 min
-rinse with distilled water
-1-2 drops iodine - 1 min
-grently wash with dH2O
-flood slides with 95% ethanol for 8-10seconds
-wash with dH2O
-safranin - 1 minute
-wash with water and gently blot dry