Class Copy

Strawberry DNA Extraction

Courtesy of Ms. Templin

Essential Questions


To extract DNA from the fruit of a strawberry plant.

Safety Precautions



  1. Place one strawberry in a Ziploc bag.
  2. Smash strawberry with hands for 2 minutes. Make sure the bag does not break.
  3. Add 10 mL of the extraction buffer to the bag.
  4. Mush again for 1 minute.
  5. Fliter through the cheese cloth in a funnel into the beaker.
  6. Pour the filtrate into the test tube so that it is 1/8 full
  7. Slowly pour the ice-cold ethanol into the test tube until it is half full.
  8. At the interface, you will see the DNA precipitate out of solution and float to the top.
  9. You may spool the DNA on the end of a glass rod.


  1. Where can DNA be found in the cell?
  2. Discuss the action of the soap (detergent) on the cell. What is the purpose of the soap in this activity?
  3. What was the purpose of the Sodium Chloride? Include a discussion of polarity and charged particles.
  4. Why was the cold ethanol added to the soap and salt mixture?
  5. Describe the appearance of your final product?
  6. Draw a diagram of DNA containing 5 sets of nucleotide bases labeling the hydrogen bonds between the bases.