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Simple DNA extraction


DNA is microscopic, but if you start with a lot of cells, you can isolate enough DNA to see it. As we begin to study DNA and the differences in genes that are within the DNA code, let us first get an idea of what it looks like.  Alright scientists, it’s time to get started!




Step 1: Pair up with your science partner.

Step 2: Get your supplies. To make sure you have everything, check them off this list:

  1. trash bag 
  2. banana baby food
  3. test tube
  4. daisy cup filled with water
  5. two empty daisy cups
  6. shampoo
  7. salt
  8. wooden skewer
  9. coffee filter
  10. spoon

Prepare your desk by covering it with a trash bag, because things could get messy!

Step 3: Squeeze a tiny amount of shampoo into the spoon (not much! only enough to fill the spoon halfway).  Add it to the water and stir. Then add a few pinches of salt to the water and stir some more. 

Step 4: Measure 5 spoons of water-soap-salt mixture and add it to the empty daisy cup. Then, measure 1 spoon of banana baby food and add it to new cup as well.

Step 5: Mix them together really well!

Step 6: This part is tricky. You or your science partner will hold a coffee filter over the remaining empty daisy cup. Then the other person will pour the banana-soap mixture into the filter.  Very gently, squeeze the coffee filter together so the clear juice filters through into the daisy cup, which all the solid clumps do not go through. Be careful not to break the coffee filter.

Step 7: Pour the filtered juice into the test tube. Then, let the teacher know!

Step 8: Your teacher will gently add an equal amount of cold ethanol to the test tube.  As soon as they do this, do not shake the test tube. The DNA will appear in the top of the liquid.  It will look like tiny white strings with bubbles all over them. Wait two minutes. 

Step 9: Take your wooden skewer and swirl it around the DNA that you see and try to pick it up!

Step 10: Congratulations, you just saw DNA that you extracted from thousands of banana cells! Record what you saw in your lab notebook. Also, record what you would have done differently if you had the chance to extract DNA again (because you may have to do this again for an experiment soon!).