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Victorian Essential Learning Standards
Use of this learning and teaching activity may contribute to achievement of elements of the Standards in Science (4,5,6) and Mathematics-Measurement (3, 4,& 5). |
Duration and Setting
1 hour in the classroom
Summary
This activity enables students to work scientifically to observe DNA - the blueprint for life. This activity may be used to provide background knowledge before students learn about selective breeding, genetic engineering and their places in food production.
Background notes for teachers
Selective plant and animal breeding have been practised for thousands of years. By choosing the best plants or animals to breed, farmers and scientists have developed offspring that are suitable for a range of reasons: their size, shape, taste or suitability to a range of climates. But how does this work? The answer lies within cells.
All living things are made up of cells. Cells are often called the building blocks of life, because they contain everything required for life. Some organisms (such as bacteria) are made up of one cell. Other organisms are made up of many cells. For example, humans are made up of an estimated 100 trillion cells!
Within each cell is Deoxyribonucleic Acid, or DNA. DNA is a molecule that contains the information or blueprint for living things. In this experiment, clumps of DNA will be visible as white strands or blobs. If we were able to view it closer, DNA would look like a spiral staircase - a double helix.
A gene is a section of DNA that contains the message for a particular characteristic, eg. the gene for green eyes. There are between 60,000 and 100,000 genes in human DNA, with a complete set in every cell. Selective breeding involves people choosing the traits of a plant or animal, by selecting individuals with those traits to breed. More recently, manipulation of DNA has occurred in science laboratories and is called genetic engineering.
Materials
From the supermarket/kitchen:
- A DNA source: broccoli, split peas and onion work well
- Cold water
- A pinch of salt
- Dishwashing detergent
- Meat Tenderiser (from the spice section of the supermarket)
- Rubbing Alcohol (look for ISOCOL in the first aid section of the supermarket). (If possible, cool in a container with iced water)
Equipment:
- A blender
- Strainer
- Bowl/large jar (to blend water and broccoli in)
- Measuring jug (500mL-1L works well)
- Chopping board and knife
For each student group:
- Small glass jars or test tubes
- Toothpicks
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What Exactly is DNA? - Worksheet
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