Protocol for Practical Classes

Subject: Nucleic Acids

Experiment 7 - extration

Materials:

Provided by the students

Onion (peeled)

Filter paper or gauze

Metods:

(the steps 1 to 6 will be performed by the professor, and them the material obtained will be splited to all the groups)

1.Cut the onion into small pieces

2.Put in a bequer the detergent, the water and the NaCl, mixing them

3.Add the onion to this solution

4.Put the bequer on the warm-bath for 15 minutes, mixing once in a while

5.Then give the solution a thermal shock placing the bequer on the ice for 5 minutes.

6.Put all in the mixer and then place the solution back in the ice for more 15 minutes.

Filter the solution into a clean bequer using the gauze (do not use the foam).

Add to it the ethanol (letting it drain on the bequer wall).

Notice the formation of two phases and the sprouting of viscous DNA wires.

Dive the baton of glass and, with circular movement in one direction, rolls the gotten filaments

Write down the results.

Objectives:

To understand how the separation of the nucleic acids based on theirs characteristics.

To verify the behavior of different groups of biomolecules in different solutions

Report suggestions:

Explain the importance of each step of the procedure and the behavior of the diverse types of biomolecules found

Explain why the DNA can be visualized .