Answer:
1A. Differential Staining is a staining process which uses more than one chemical stain. Using multiple stains can better differentiate between different microorganisms or structures/cellular components of a single organism.
2. Unlike negative staining, positive staining uses basic dyes to color the specimen against a bright background. ... The negatively charged cell wall of many microorganisms attracts the positively charged chromophore which causes the specimen to absorb the stain giving it the color of the stain being used.
3. Gram-staining is a differential staining technique that uses a primary stain and a secondary counterstain to distinguish between gram-positive and gram-negative bacteria. Stains cells purple or blue. mordant, makes the dye less soluble so it adheres to cell walls.
4. The process involves three steps:
Cells are stained with crystal violet dye. ...
A decolorizer such as ethyl alcohol or acetone is added to the sample, which dehydrates the peptidoglycan layer, shrinking and tightening it. ...
A counterstain, such as the weakly water soluble safranin, is added to the sample, staining it red.
5. Heat fixing denatures bacterial enzymes, preventing them from digesting cell parts, which causes the cell to break, a process called autolysis. The heat also enhances the adherence of bacterial cells to the slide. It removes water from the bacterial cell, pores open in the cell so more stain can enter the cell wall.
6. To measure an object seen in a microscope, an ocular micrometer serves as a scale or rule. This is simply a disc of glass upon which equally spaced divisions are etched. ... To use the ocular micrometer, calibrate it against a fixed and known ruler, the stage micrometer.
Explanation:
