GRAM STAINING

 Introduction:
Gram staining is a method of differentiating bacterial species into two large groups: Gram positive and Gram negative.

Objectives:
1. Differentiate yogurt bacteria (Streptococcus and Lactobacillus)
2. Relate the staining procedure with the structure of the cells.

Material:
- Slide
- Cover slip
- Tongs
- Needle
- Gram stain: crystal violet, iodine and safranin
- Decolorize reagenti: ethanol 96%
- Microscope
- Yogurt

Procedure:
1. Fix the piece go yogurt
2. Add crystal violet (1 minute and 30 seconds)
3. Add water
4. Add Lugol (1 minute)
5. Add water
6. Add ethanol
7. Add safranin (1 minute)
8. Add water

Observations:

We can see the bacteria of the yogurt 

MITOSIS IN AN ONION ROOT

Introduction: 
In this experiment we will see the parts of the mitosi (interfase, profase, metafase, anafase and teloface) in a onion root.

Material:
- Microscope
- Slide
- Coverslip
-Dropper
-Needles emmanegades
- Watch glass
- Beaker
- Thin tongs
- lighter
- Cellulose paper

Quemical products: distilled water, Orceine A and B and normal water.
Natural products: Onion

Procedure: 

1). Put the onion in a beaker with water one week (the roots need to touch the water). 

2). When the roots grow up 3cm, cut the final 4 mm and put in the watch glass with orceine A. 

Then, you need to put in  the heater with the flame of the lighter until you see vapor (In this process the temperature can't pass the 60 C). 

3). With the tongs take the piece of the root and put in a slide and put the orceine B with the dropper. 

4). Put the coverslip and with a piece of cellulose paper you need to push and turn in the coverslide to extend de cells. 

5). Observe with the microscope with 600 increases and you will see the parts of the mitosi. 

Observations: 

In this experiment we can't see very well the different parts of the mitosis.