Making DNA at home!

Hop to it…

With the Easter holidays just around the corner we’ve come up with a fun-filled, budget friendly activity you can all try at home with your little ones during the school holidays.

What’s even better is that it’s scientific & educational too! 🙂

How to make DNA in your kitchen!

strawberry_DNA

What you need:

  • What you need:
  • What you need:
  • 2 glass bowls
  • A small glass with straight edges
  • Food processor
  • Sieve
  • Coffee filter papers
  • Ice cold Isopropanol (a “rubbing alcohol” that can be found in pharmacies. Place in the freezer to make it ice cold, it will not freeze)
  • Sale
  • Warm water
  • Washing up liquid
  • 2 small strawberries
  • Esky filled with ice
  • Toothpicks
  • Knife
  • Chopping board

 

How to do it!

  1. Dissolve 1 teaspoon of salt into 100ml of water
  2. Finely chop the strawberry (The science bit: this separates the strawberry cells)
  3. Place the strawberries and the salt water in a processor and blend for a few minutes. (The science bit: salt helps the DNA precipitate)
  4. Pour the lumpy strawberry mixture in to a bowl
  5. Add a squirt of washing up liquid (The science bit: soap destroys the cell membrane, releasing cell contents, like DNA)
  6. Place the bowl in the Esky of ice (or in the fridge) for 5 minutes, stirring occasionally (The science bit: ice slows down enzymes that would degrade the DNA)
  7. Place the coffee filter paper into the sieve over a bowl
  8. Pour the strawberry mixture in to the filter paper and collect the filtered liquid in the bowl
  9. Pour some of the liquid in to the small glass
  10. Tilt the glass gently, pour the ice cold isopropanol down the side of the beaker so that it forms a layer on top of the juice (The science bit: alcohol dehydrates the DNA causing it to precipitate)
  11. Gently stir the top layer with a toothpick but do not mix the two layers
  12. Snotty looking white strands should form in the top layer – THIS IS DNA!

 

So, where did the DNA come from?

First thing to note is that ALL living things contain DNA.

Every living thing is made up of cells which are essentially tiny little building blocks from human skin to strawberries. Invisible to the naked eye these can only be viewed through a microscope.

Inside all our cells & the cells of anything living there is a collection of chromosomes.

Chromosomes are made of VERY long strands of DNA.

Diagram

 

DNA is essentially a blueprint of instructions that tell our cells and our whole body how to work. Our DNA makes us human just as a strawberry’s DNA makes it a strawberry.

By chopping up the strawberry and using the washing up liquid we have broken open the cells (washing up liquid dissolves the outside of the cells) and released the contents, including the DNA, into the salty water.

By filtering the lumpy strawberry mixture we remove most of the rubbish that is left when the cells are broken up. The liquid that we keep contains the DNA.

DNA is normally far too small to see (even with a microscope) but adding the alcohol to the top of the strawberry juice causes the DNA molecules to clump together. Eventually, enough DNA clumps together so that we can actually see it!

 

 

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