Why is dye used to view bacteria through a light microscope? What are the steps in Gram staining?
What structures do plant cells possess that animal cells do not? What is the function of these structures?
What test tubes were the experimental tubes? Which were the controls? What purpose do controls in an experiment?
Importance of dye:
Bacteria are minute and invisible to the naked eye. Organisms such as Protozoa, yeast and algae can be viewed at 200X and 400 X magnifications but bacteria can only be viewed at 1000X.Even at this magnification, bacteria can't be observed unless stained. By using stain the following can be observed.
1. Shape of microorganism
2. Relative size of the microorganism
3. Variations in size and shape of microbes.
It consists of four components
1. Primary stain: Gentian violet is used.
2. Mordant: Gram's Iodine is used.
3. Decolourizer: Ethyl alcohol, acetone or 1:1 ethanol-acetone mixture is used.
4. Counterstain: Dilute carbol fuchsin, safranin or neutral red is used.
1. Smear is prepared on a glass side.
2. It is stained by primary stains such as gentian violet. This is the mixture of crystal violet and methyl violet.
3. It should be washed after one minute of exposure.
4. The smear is treated with few drops of Gram's Iodine. The exposure time should be one minute. ...
The prophase of mitosis is contrasted to the prophase I of meiosis. How the prophase of mitosis differs from prophase I of meiosis is determined.