Suppose you are viewing a smear of a pure sample and you see both pink-red and purple cocci what is going on here?

1. When viewed under a microscope Gram positive bacteria appear pink or red?
2. What are they if bacteria stain purple or pink?
3. Why would a gram positive stain pink?
4. What determines if a bacterial cell is Gram positive or Gram negative?
5. Can gram positive appear gram negative?
6. What is a bacterial smear?
7. Why is the color of the Gram (+) organism purple?
8. Which bacteria appears purple violet after Gram staining?
9. Which one is stained purple by Gram staining?
10. What Colour is gram-positive?
11. What Gram stain is Streptococcus?
12. What means gram-positive?
13. What determines if a bacterial cell is Gram positive or Gram negative quizlet?
14. What does gram negative mean in bacteria?

When viewed under a microscope Gram positive bacteria appear pink or red?

11) View the slide with the light microscope under oil-immersion. Gram-positive bacteria appear blue or violet and gram-negative bacteria appear pinkish red.

What are they if bacteria stain purple or pink?

A Gram stain is colored purple. When the stain combines with bacteria in a sample, the bacteria will either stay purple or turn pink or red. If the bacteria stays purple, they are Gram-positive. If the bacteria turns pink or red, they are Gram-negative.

Why would a gram positive stain pink?

Protocols Gram Stain Protocols

Gram-positive bacteria have cell walls that contain thick layers of peptidoglycan (90% of cell wall). These stain purple. Gram-negative bacteria have walls with thin layers of peptidoglycan (10% of wall), and high lipid content. These stain pink.

What determines if a bacterial cell is Gram positive or Gram negative?

Gram positive bacteria have a thick peptidoglycan layer and no outer lipid membrane whilst Gram negative bacteria have a thin peptidoglycan layer and have an outer lipid membrane.

Can gram positive appear gram negative?

If the decolorizing agent is applied on the cell for too long time, the Gram-positive organisms to appear Gram-negative. Under-decolorization occurs when the alcohol is not left on long enough to wash out the CV-I complex from the Gram-negative cells, resulting in Gram-negative bacteria to appear Gram-positive.

What is a bacterial smear?

A bacterial smear is simply that—a small amount of culture spread in a very thin film on the surface of the slide. To prevent the bacteria from washing away during the staining steps, the smear may be chemically or physically “fixed” to the surface of the slide.

Why is the color of the Gram (+) organism purple?

Gram staining is a common technique used to differentiate two large groups of bacteria based on their different cell wall constituents. ... Gram positive bacteria stain violet due to the presence of a thick layer of peptidoglycan in their cell walls, which retains the crystal violet these cells are stained with.

Which bacteria appears purple violet after Gram staining?

Which bacteria appears purple-violet colour after staining? Explanation: Gram-positive bacteria retain the crystal violet and hence appear deep purple-violet colour as it has a higher content of the peptidoglycan layer.

Which one is stained purple by Gram staining?

A purple stain (crystal violet) is used to stain the bacteria first, the stained bacteria are decolorized and then stained with a red stain (Safranin). Bacteria with thick cell walls keep the first (purple) stain and are called Gram positive.

What Colour is gram-positive?

The staining method uses crystal violet dye, which is retained by the thick peptidoglycan cell wall found in gram-positive organisms. This reaction gives gram-positive organisms a blue color when viewed under a microscope.

What Gram stain is Streptococcus?

Streptococci are Gram-positive, nonmotile, nonsporeforming, catalase-negative cocci that occur in pairs or chains. Older cultures may lose their Gram-positive character.

What means gram-positive?

Gram-positive bacteria are bacteria with thick cell walls. In a Gram stain test, these organisms yield a positive result. The test, which involves a chemical dye, stains the bacterium's cell wall purple. Gram-negative bacteria, on the other hand, don't hold the dye.

What determines if a bacterial cell is Gram positive or Gram negative quizlet?

Because of the differences in the structure of their cell wall. Because of the thickness of peptidoglycan in their cell walls. Those with thick peptidoglycan in their wall are stained purple and are known as Gram positive. Those with thin peptidoglycan and an outer membrane stain pink and are known as Gram negative.

What does gram negative mean in bacteria?

Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation.