What is a restriction enzyme?
Restriction enzyme is a protein that cuts DNA at particular base sequences.

What is restriction enzyme role in nature?
The role of the restriction enzyme inside bacteria is to protect  them against viral DNA infection.

Why does DNA migrate toward positive electrode?
DNA migrates toward positive electrode at pH 8.0 it's negatively charged.
What is the TBE composition?
The TBE composition is: NaCl, Tris-HCl and Mg²⁺ ions.

Why is important to add Mg ions? Are they co-enzymes or cofactors?
It's important to add Mg ions because they favor the digestion of DNA. They are cofactors.

How can DNA be detected in agarose gel?
DNA can be detected in agarose gel by using an intercalant dye and putting it under UV linght (transilluminator).
Why are DNA dyes dangerous for human health?
DNA dyes are dangerous for human health because they contain mutagenics substances, dangerous for our DNA.

What should be done to prepare an agarose gel?
To prepare an agaorose gel we should: put agarose powder in a conic flask; add 10mL of TAE; put the conic flask in a microwave owen until the solution is completely transparent; pour the solution in the gel tray and create wells by using a comb.

What should not be done preparing an agarose gel?
When we are preparing an agarose gel we shouldn't done: pour quickly the solution in the gel tray; don't leave bubbles in the gel; don't leave the conic flask inside the microwave without checking it.
Which piece of information can be find out from a DNA pattern bands?
From DNA pattern bands we can discover who is the culprit of a crime.