Tuesday, July 6, 2010

Science Lab

Today we did a science lab where we were able to extract DNA from peas.  The first thing we did was we blended ½ cup of split peas with one cup of cold water and 1/8 a teaspoon of salt.   The reason we blended the peas with the salt water was to break apart the cell wall and separate all of the cells.

If you wanted to you could find the DNA out of a hamburger, however you would not be able to find the DNA in a grain of sugar, salt or anything non-living like rocks and minerals because they don’t have cells. 

We learned a lot today and had fun doing it!
Kim, Crystal Springs

 
After we blended the peas we strained out all of the pulp so that we would only have a really thin pea-cell soup left.  Once we strained the soup we added 2 tablespoons of liquid detergent like Dawn dish soap, and let it sit for about five to ten minutes.

 





After letting the soap/pea mixture sit for a few minutes to break down the cell membrane, which is a lipid.  We then poured our mixture into a test tube.  We added a pinch of enzymes to pull the DNA out of the cell and eliminate the proteins that surround the DNA.  After carefully stirring the mixture, we added rubbing alcohol into the test tube.  The DNA will rise into the alcohol so you will be able to see the DNA floating inside the layers of alcohol.  The alcohol will look like white spider webs in a stringy mass.  It is really amazing to be able to extract DNA because if you were to try to look at a one single strand of DNA it would take a very expensive and advanced microscope.  However, you can look at clumps of them with your naked eye!


 

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