The performance of the Gram Stain on any sample requires four basic steps that include applying a primary stain
(crystal violet) to a heat-fixed smear, followed by the addition of a mordant (Gram’s Iodine)
, rapid decolorization with alcohol, acetone, or a mixture of alcohol and acetone and lastly, counterstaining with …
What are the 5 steps of Gram staining?
- Crystal Violet (the Primary Stain)
- Iodine Solution (the Mordant)
- Decolorizer (ethanol is a good choice)
- Safranin (the Counterstain)
- Water (preferably in a squirt bottle)
What are the staining procedures?
A variety of staining techniques can be used with light microscopy, including Gram staining,
acid-fast staining, capsule staining, endospore staining
, and flagella staining.
What is the order of Gram staining?
The stains are applied to a smear of bacteria on a microscope slide in the following order:
crystal violet, Gram’s iodine, decolorizing agent, and safranin.
Which is the most crucial step in the Gram staining procedure?
The critical step of the Gram staining procedure is
the decolorization step
. Hold the slide in a tilted downward position and allow the decolorizer to flow over the smear.
What is the most important step in any staining procedure?
One of the most important steps in Gram staining is
the decolorizing step (use of alcohol/acetone)
. If the decolorizer is not left on long enough, then it will not be able to differentiate between Gram positive and Gram negative bacteria. This step uses decolorizer, made of an alcohol/acetone mixture.
What is the correct order of staining reagent in Gram staining?
Explanation: Gram staining is a type of differential staining. In this process the fixed bacterial smear is subjected to the following staining reagents in the order listed:
crystal violet, iodine solution, alcohol (decolorizing agent), and safranin
. 3.
What is the most important reagent in the Gram stain method?
The primary stain of the Gram’s method is
crystal violet
. Crystal violet is sometimes substituted with methylene blue, which is equally effective. The microorganisms that retain the crystal violet-iodine complex appear purple brown under microscopic examination.
What are the 4 steps of Gram staining?
The performance of the Gram Stain on any sample requires four basic steps that include applying a primary stain (crystal violet) to a
heat-fixed smear, followed by the addition of a mordant (Gram’s Iodine), rapid decolorization with alcohol, acetone, or a mixture of alcohol and acetone and lastly, counterstaining with
…
What are the steps of simple staining in the correct order?
- Prepare slide for staining.
- Apply crystal violet.
- Apply iodine.
- Decolorize.
- Apply safranin.
- Rinse with water and blot dry.
What is the most critical step in the gram staining procedure Why?
The most critical step in the Gram stain is
the decolorizer step with acetone alcohol
. If the decolorizer is left on too long Gram positive bacteria will come out pink and if it is not left on long enough the Gram negatives will come out purple.
In which step of the gram staining procedure is the timing most important and why?
Why
decolorizing
is the most critical steps in gram stain? The decolorizing is the most critical step in gram staining. We use decolorizing solution either alcohol or acetone and it is generally time bound.
What is the correct order for the Gram stain quizlet?
List the 4 reagents used for the gram stain in the proper order?
Crystal violet stains gram positive and gram negative cells
. Iodine is used next as mordant. Alcohol decolorizes the gram negative cells, and lastly Safranin counterstains gram negative cells.
What is the principle behind the Gram stain reaction?
The basic principle of gram staining involves
the ability of the bacterial cell wall to retain the crystal violet dye during solvent treatment
. Gram-positive microorganisms have higher peptidoglycan content, whereas gram-negative organisms have higher lipid content.
Which of the four staining procedures is the most important?
The Gram stain
is the most important staining procedure in microbiology. It is used to differentiate between gram positive organisms and gram negative organisms.
What is the purpose of Gram stain?
A Gram stain is most often used to find out
if you have a bacterial infection
. If you do, the test will show if your infection is Gram-positive or Gram-negative. A Gram stain may also be used to diagnose fungal infections.
How do you make a Gram stain reagent?
Dissolve 2.0 g certified crystal violet into 20.0 ml of 95% ethyl alcohol.
Dissolve 0.8 g ammonium oxalate into 80.0 ml distilled water
. Mix the two solutions together and allow them to stand overnight at room temperature (25°C). Filter through coarse filter paper before use.
Which is the key step of the Gram stain procedure if this is not done right the results will be wrong?
The decolorization of the cells
is the most “operator-dependent” step of the process and the one that is most likely to be performed incorrectly. Rinse with water to stop decolorization. Rinse the slide with a counterstain (safranin or carbol fuchsin) which stains all cells red.
What are the 4 reagents used in Gram staining?
- Crystal violet (primary stain) [1]
- Gram’s iodine solution (the mordant) [1]
- Acetone/ethanol (50:50 v:v) (the decolorizer) [1]
- 0.1% basic fuchsin solution (the counterstain) [1]
- Water.
Which of the following steps of the Gram stain is called the differential step?
Gram’s decolorizer, a mixture of ethyl alcohol and acetone, is then added
. This is the differential step. Gram-positive bacteria retain the crystal violet-iodine complex while Gram-negative are decolorized. 4.
What step in Gram staining procedure is the most crucial and may lead to poor result if not done properly?
Excessive Decolorization
It is clear that
the decolorization step
is the one most likely to cause problems in the Gram stain. The particular concerns in this step are listed below. Heat fixing the cells, when done to excess, alters the cell morphology and makes the cells more easily decolorized.
What is the purpose of the 95% ethanol step in the Gram staining procedure?
Remel Gram Decolorizer (95% Ethyl Alcohol) is a
reagent recommended for use in qualitative procedures to differentiate gram-negative from gram- positive organisms
. The primary stain, crystal violet, is a basic dye which rapidly permeates the cell wall of all bacteria, staining the protoplast purple.
What is the most critical step in the Gram staining procedure quizlet?
the decolorizer step
is the most critical because too much destaining reagent can remove the dye-mordant complex from the cells, which makes the gram-positive cells appear to be falsely gram-negative.
What are the four reagents used in Gram stain quizlet?
- Crystal violet (primary stain)
- Iodine (mordant)
- Alcohol wash (decolorization)
- Safranin (counterstain)
What are the reagents needed for the Gram stain procedure quizlet?
- Crystal violet – primary stain.
- Grams iodine – mordant.
- Alcohol – decolorizer.
- Safranin – counterstain.
What is differential staining describe the principle and procedure of Gram staining?
The Gram stain technique is
based on the differential structure of the cellular membranes and cell walls of the two groups
. Gram-positive organisms contain a highly cross-linked layer of peptidoglycan that retains the primary dye, crystal violet (CV), following the application of the mordant, iodine (I).
