By Diane Thajeb, Nicky Fernandez, and Stephanie Harris

What we did for this lab…We did a lab to extract DNA from living

things in order to learn more about DNA.These are the items included:Warm water bath, centrifuge, micropipettors,

micro centrifuge, buccal swab, sample tubes, lysis solution, concentrated salt solution, resuspension buffer, ethanol, isopropyl alcohol

Steps• We collected the cheek cells of a person using

the buccal swab and put it into an Eppendorf tube.

• We cut off the end of the swab when we did this so we could close the tube.

• Using the micropipepttor, we added some lysis solution to the tube. Lysis means to separate, it is used in DNA extraction to separate the cell membrane in the cell. After the cell membrane “explodes”, it turns into a series of debris.

StepsPlace the Eppendorf tube in the warm water

bath so that the DNA could be freed from the cell.

Remove the swab from the Eppendorf tube and add some concentrated salt solution to the tube using the micropipetor. The concentrated salt solution causes the debris and other proteins to clump together.

Steps• Place the tube into the centrifuge. In order to

balance the centrifuge a tube containing water is placed opposite of the tube.

• Inside the centrifuge the tubes spin around at high speeds. The heavy clumps of protein and cellular debris sink to the bottom of the tube while the DNA strands remains distributed throughout the liquid. This is done so we could separate the DNA strands from the other stuff.

Steps• Using the micropipettor, we removed the top

liquid that contains DNA from the tube and placed it in a clean tube. The debris and other proteins stay behind in the tube.

• We added some isopropyl alcohol to the tube and shook the tube. By shaking the tube, the isopropyl alcohol and the DNA solution is inverted. The DNA solution does not stay dissolved and comes out of the solution, then it was able to be seen with the naked eye.

StepsPlace the tube in the micro centrifuge, this

will make the contents in the tube spin around. The DNA thus sunk to the bottom of the tube.

Once the liquid is removed and the DNA is allowed to dry, you can re-dissolve it in the solution of your choice if you want.

What We LearnedDNA ExtractionDNA is isolated for various reasons,

including: genetic testing, body identification, and analysis of foreign evidence

DNA extraction is the first step in a DNA lab process

DNA needs to be extracted from proteins and cellular contaminants in order to properly analyze it

DNA is in Cells

How DNA Was DiscoveredWatson, a biologist, and Crick, a physicist,

were working together in a laboratory in Cambridge, England in the early 1950’s.

Pauling, a chemist, had discovered an important structure of protein in 1951

Wilkins, a physicist, took the first x-ray pictures of DNA, and resulted in his idea that DNA structure could be helical.

How DNA Was Discovered(Continued)Watson and Crick had similarly suggested a

three helical model in 1951 but the theory ultimately proved incorrect

Franklin's photo-51 soon sent them in the right direction

The picture itself showed DNA that had been crystallized and showed a blurred X in the centre of the molecule, revealing a helical structure.

From this, their model of DNA was published.

What is DNA?DNA, or deoxyribonucleic acid, is the

hereditary material in humans and almost all other organisms.

Nearly every cell in a person’s body has the same DNA.

The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T).

What is DNA?(Continued)

DNA bases pair up with each other, A with T and C with G, to form units called base pairs.

An important property of DNA is that it can replicate, or make copies of itself.

An important property of DNA is that it can replicate, or make copies of itself.

This is critical when cells divide because each new cell needs to have an exact copy of the DNA present in the old cell.

How DNA WorksWhen the first cell is formed, you are given

the complete genetic code that all of your cells will use for the rest of your life.

In that first cell, half of the chromosomes (half of the DNA molecules) came from your father and the other half came from your mother.

The cell will then divide into other cellsDNA copies go to each cell in this process