L:17 Gram staining

L:16

 Introduction:

 In this great experiment we yogurt bacteria stained with dyes to diferend observarlos microscope after.

Objectives:

1- Differentiate yogurt bacterias.
2- Relate the staining procedure with the structure of the cells.

Materials:

- 1 Slide
- 1 Cover slip
- Tongs
- Needle
- Gram stain: Crystal violet,iodine and safranin.
- Decolorize reagents: ethanol 96%
- Microscope
- Yogur

Procedure:

Prokariotic cell observations: Gram Staining

1- Prepare a heat-fixed sample of the bacteria to be stained
2- Cover thesmear with crystal violet for an exposure of 1 min
3- Rinse with distilled water
4- Apply Iodine solution for 1 min.
5- Rinse the sample with distilled water.
6- Decolorize using ethanol.Drop by drop until the purple stop flowing.Wash immediately with distilled water.
7- Cover the sample with the safranin stain for an exposure time of 45seconds.
8- Rinse the sample with distilled water.
9- Gently dry the slide with paper(only the under pard of the slide )



Questions:

Gram Stain:

1.Complete the table thay you have below:

	GRAM+	GRAM-
Crystal violet: Color?	VIOLET	VIOLET
Iodine	Color changes	Color changes
Ethanol Decolorize?	No Dye	Colorfast
Safranin Color?	No Dye	Dyed Pink

Photo the yoghurt bacteria

Microscope optical

http://microbiologiabactesp3.blogspot.com.es/2009_08_01_archive.html