Perform a DNA extraction from green peas at home or school lab, under adult supervision, by following the given procedure carefully.

Procedure for DNA extraction:

To half cup of split peas, add 1/8 teaspoon of salt and one cup of cold water.
Transfer this mixture in a blender and blend it on high speed for 15 seconds.
Filter the blended mixture, using a strainer, into a measuring container. Observe the amount of mixture you obtain after filtration. Add liquid detergent equal to 1/6 volume of the obtained pea mixture.
Mix by swirling. Allow the mixture to rest for about five to ten minutes.
Transfer this mixture to test tubes. Fill the tubes to about 1/3 of their volume.
Add a pinch of meat tenderizer to each of these tubes. Mix gently to avoid damaging the DNA.
Tilt the test tube, and pour alcohol (75% isopropyl alcohol or 95% ethanol) down the sides of the tube. Add alcohol to about 2/3 volume of the tube. You will obtain two layers. The layer at the top contains the DNA.

Now that you are done with the DNA extraction process, answer the following questions:

What purpose does blending the pea mixture serve?
Why do you need to add liquid detergent?
What role does the meat tenderizer play?
Why is alcohol added and why does the DNA get extracted in the alcohol layer?

DNA resides in the nucleus, which is enclosed by the nuclear membrane. The nucleus is further enclosed by the cell membrane. So, to get the DNA, we need to break open both the membranes. Cell membranes are made up of lipids and proteins. The detergent molecules to attach to the cell and nuclear membranes, causing them to break open.

Meat tenderizer contains the enzyme protease that helps cleave proteins. Even after breaking open the nucleus and cell membrane, the DNA is still protected by cell proteins. Meat tenderizer cleaves the proteins, leaving behind only the DNA molecule.

DNA is insoluble in alcohol and hence, when alcohol is added, it precipitates out the DNA.

Explanation:

PLATO Answer