Simple and Negative Stains Flashcards

Flashcards about Simple and Negative Stains

What is the application of simple stains?

To enhance contrast by coloring bacterial cells, allowing observation of cell shape and arrangement.

What shape is a coccus cell?

Spherical.

What shape is a bacillus cell?

Rod-shaped.

What shape is a coccobacillus cell?

Short oval rod.

What shape is a spiral cell?

Curved or twisted shape.

What shape is a spirochete cell?

Corkscrew shaped.

What shape is a vibrio cell?

Comma shaped, curved rod.

What cell arrangement is described as 'single'?

Individual cell.

What cell arrangement is described as 'diplo'?

Pairs.

What cell arrangement is described as 'strep'?

Chains.

What cell arrangement is described as 'tetrad'?

Group of 4.

What cell arrangement is described as 'staph'?

Grape-like cluster.

What is a chromagen?

Color molecule consisting of a chromophore (color-bearing part) and auxochrome (charged portion).

What are basic stains?

Positively charged stains that are attracted to negatively charged bacterial cell walls.

Give examples of a basic stain

Methylene blue, crystal violet, safranin.

What is the purpose of heat fixation?

To kill the cells and preserve their morphology.

Describe negative staining.

Stains the background, not the cells.

What is an advantage of negative staining over simple staining?

Allows observation of the true morphology and size of cells without distortion.

Why does negative staining have less distortion in cell shape and size?

No heat fixation.

What are acidic stains?

Negatively charged stains that are repelled by the negatively charged cell wall.

Give examples of a acidic stains

Nigrosin, india ink.