The DNA becomes solid and forms cloudy clumps.
All living things contain DNA. It’s the stuff that tells cells how to grow and function! In this activity, you can have a go at extracting DNA from fruits around your house.
Safety: This activity involves cutting fruits with a knife and hot water. Ask an adult to help.
DNA is the key to life! DNA, which stands for deoxyribonucleic (DEE-oxy-RYE-bo-NEWK-lay-ik) acid, is a long string of chemical parts, and it contains all the information to make a living thing. DNA is stored inside almost all living cells. So the first step in extracting DNA is to rip apart all those cells!
To get DNA from a cell, scientists typically use fancy extraction kits to conduct their experiments. In these experiments, a detergent helps to pop open the cells. This process is called lysis (LIE-sis). In this activity, we made the fruit cells undergo lysis with the dishwashing detergent. Using hot water speeds up this process and helps more fruit cells to burst open and release their DNA into the extraction liquid. Adding salt to the extraction liquid helps tiny DNA strands to clump together, making it easier to separate the DNA from the proteins in the fruit cells.
Many cells contain DNases, which are chemicals that break down DNA. DNases are released if cell walls are broken, which can happen if viruses attack. However, we can slow this process by cooling the solution down. This is why we used the ice-cold rubbing alcohol.
At this stage, there are all kinds of chemicals in our solution – proteins and enzymes and fragments of cell walls. Pretty much all of it will dissolve in rubbing alcohol, but not the DNA. That means the DNA becomes solid and forms cloudy clumps. Now it’s time to investigate if you can extract DNA from other fruits or veggies!
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13 May, 2023 at 7:30 am
WoW … what a fantastic activity the extracting dna is…off to buy rubbing alcohol…