Why Is Decolorization An Important Step In A Differential Stain Quizlet?

The decolorizer dissolves the lipids, increasing cell-wall permeability and allowing the crystal violet-iodine complex to flow out of the cell. The color of the counterstain must contrast with that of the primary stain. A counterstain such as safranin stains gram-negative cells red.

Why is it important to use a differential stain?

Differential staining is used to detect abnormalities in the proportion of different white blood cells in the blood. The process or results are called a WBC differential. This test is useful because many diseases alter the proportion of certain white blood cells.

What happens if Decolorizer is not left on long enough?

It is possible to leave the decolorizer on too long and strip the blue stain out of all the bacteria, even the Gram positive ones. … If the decolorizer is not left on long enough, the blue color will remain in the Gram negatives and they will appear Gram positive (purple) Page 4 c.

What happens if you add too much Decolorizer?

Do NOT decolorize for a full minute!

The decolorizer should stay on the slide for no more than 15 seconds! If the decolorizer is left on too long, even gram positive cells will lose the crystal violet and will stain red.

What is the most important step in differential stain?

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 is the benefit of using a differential stain versus a simple or negative stain?

A simple stain will generally make all of the organisms in a sample appear to be the same color, even if the sample contains more than one type of organism. In contrast, differential staining distinguishes organisms based on their interactions with multiple stains.

What is an example of a differential stain?

Differential stains use more than one stain, and cells will have a different appearance based on their chemical or structural properties. Some examples of differential stains are the Gram stain, acid-fast stain, and endospore stain.

Why do we prefer stains with positively charged chromogen?

Basic stains with a positively charge chromogen are preferred because bacterial nucleic acid and certain cell wall components carry a negative charge that strongly attract and binds to the cationic chromogen. … If fail to heat fix, the bacteria will wash away when staining.

Why is ethanol used in Gram staining?

Ethyl alcohol is a nonpolar solvent, and thus penetrates the cell walls of Gram negative cells more readily and removes the crystal violet-iodine complex. However, caution must be used since applying the decolorizer too long will remove dye complexes from the Gram positive cells as well.

What is the principle of Gram staining?

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.

What is the most important step in Gram staining?

The thickness of the smear used in the Gram stain will affect the result of the stain. The step that is most crucial in effecting the outcome of the stain is the decolorizing step.

What is the difference between doing a simple stain versus a differential stain on a bacterial slide?

What is the difference between doing a simple stain versus a differential stain on a bacterial slide? The simple will only tell you morphological shape and size, while the differential stain will allow for determination of size, shape, and type of the cell wall.

Why is it important to use fresh cultures in the Gram staining technique?

First, older bacterial cells may have damage to their cell walls that causes them to appear gram-negative even if the species is gram-positive. Thus, it is best to use fresh bacterial cultures for Gram staining. Second, errors such as leaving on decolorizer too long can affect the results.

What is the correct order of steps in a Gram staining procedure?

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 is a good definition of a differential stain?

Definition. The dye or stain that is used to differentiate one component or cellular structure from another, or to differentiate an entity from another in a specimen.

Why is Gram stain considered differential?

why is the gram stain considered a differential stain? the gram stain differentiates two types of bacteria based on the composition of their cell walls. … old cultures of gram positive cells may not retain stain as well as younger cultures and could give false negative results (ex) pink cells.

What is the difference between a simple stain and a differential stain quizlet?

Simple stain uses 1 dye to increase contrast of cells. A simple stain determines size, shape, and arrangement of cells but cannot differentiate between types of bacteria. A differential stain uses 2 or more dyes to differentiate between organisms or between cell structures.

What is the difference between simple and differential staining?

1. What is differential staining? A simple stain will generally make all of the organisms in a sample appear to be the same color, even if the sample contains more than one type of organism. In contrast, differential staining distinguishes organisms based on their interactions with multiple stains.

Is a simple stain positive or negative?

SIMPLE STAIN:

It is a cationic dye (positive charge) which stains the cell a blue color. The presence of negatively charged molecules in the cell (like DNA & RNA) causes the cell to stain blue.

What is the most common differential stain used in microbiology?

The Gram stain is the most common differential stain used in microbiology.

What are the factors that can influence gram stain results?

The many variables that can affect this stain are age of the culture, amount of decolorizer used, the time of decolorization, the type of organism (acid-fast bacteria and spores do not stain well), thickness of the smear, and the general care of the stainer.

What happens if you reverse crystal violet and safranin stains?

If there is a reversal of crystal violet and safranin stains, then the cross-link between iodine and crystal violet won’t happen, and during decolorization, the safranin will fade away. Ans also, as crystal violet stain is used in the last, it will make all cells purple.

What happens if you use safranin as the primary stain?

If you reverse the staining procedure that is using safranin first, this will cause all the bacteria to remain red and crystal violet applied later on may cause the gram-negative bacteria to become violet in color and the gram -positive bacteria will remain red.