Using Onions in the Lab


Onions can cause interest as well as tears in the classroom. Easy and cheap to source, they make a great resource for looking at cell structure, particularly stomata, and for extracting DNA, much more reliably than kiwi fruits.


Teaching Topics

  • Cell structure
  • Stomata
  • DNA
  • Enzymes


Onion, Allium ceta

Onions have been cultivated for many centuries. Along with chives, leeks, garlic and shallots they belong to the genus Allium with their characteristic smell caused by alkyl sulphides.

Growing and sourcing

Obtaining: Easily obtained from greengrocers, markets and supermarkets at reasonable cost. A small number can provide the material for several investigations. Although some awarding bodies suggest the use of kiwi for extracting DNA, there is a problem with pectin levels. We suggest onion as a better option.

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