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Biotechnology and Biomedical Engineering
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Microbiology Virtual Lab I
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Gram Stain Technique
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Gram Stain Technique
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Theory
Procedure
Self Evaluation
Animation
Simulator
Assignment
Reference
Feedback
1)
The Gram stain differentiates between bacteria is based on the composition of their _________
Nucleus
Cell Membrane
Mitochondria
Cell Wall
2)
What happens when under decolourised?
All cells appear pink
All cells appear blue
Gram negatives appear purple
Gram positives appear pink
3)
What happens when over decolourised?
All cells appear pink
All cells appear blue
Gram negatives appear purple
Gram positives appear pink
4)
____________dissociates in aqueous solutions into CV+ and chloride (Cl – ) ions.
Crystal Violet
Methyl Blue
Grams Iodine
Safranin
5)
What composes the thick cell wall of a gram positive bacteria?
LPS
Peptidoglycan
Sphingomyelin
Meso-diaminopimelate
6)
Which bacteria have an outer layer located outside the peptidoglycan layer?
Gram positive
Gram negative
7)
Which are the two sugars make up the peptidoglycan layer?
N-acetylglucosamine & meso-diaminopimelate
N-acetylmuramic acid & lipopolysaccharide
Meso-diaminopimelate & lipopolysaccharide
N-acetylglucosamine & N-acetylmuramic acid
8)
Which bacteria has a thicker cell wall?
Gram positive
Gram negative
9)
Most bacteria have at least how many layers in their cell envelope?
One
Two
Three
Four
10)
Which are the primary stain and counter stain used in Gram Staining
Crystal Violet and safranin
Crystal Violet and grams iodine
Safranin and grams iodine
Acetone and Crystal Violet
11)
Before you use your reagents to stain the bacteria, you need to heat fix your sample first by waving the slide through the blue flame on a Bunsen burner a few times. Why do you do this?
So that the bacteria will react to the stain
So that the bacteria will not be washed off
So that the bacteria will not die
So that the morphology of bacteria change
12)
Which is the crucial step in Gram Staining?
Smear preparation
Alcohol/Acetone addition
Crystal Violet addition
Grams Iodine addition
13)
Which of these factors will not affect your Gram stain results? (Given that everything else is done correctly.)
Reagent Quality
Sample Thickness
Excessive Washing of Slide
Bacterial Age
14)
What colour do Gram positive and Gram negative bacteria take; respectively?
Yellow and Orange
Pink and Purple
Purple and Pink
Orange and Yellow
15)
Role of mordant in Gram Staining
Fixes safranin to cell wall
Helps in decolourisation
Helps the cells look red
Fixes the primary stain to the cell wall
Cite this Simulator:
vlab.amrita.edu,. (2011). Gram Stain Technique. Retrieved 18 April 2024, from vlab.amrita.edu/index.php?sub=3&brch=73&sim=208&cnt=3
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