Victorian Curriculum Links

Science Understanding

Scientific understandings, discoveries and inventions are used to inform personal and community decisions and to solve problems that directly affect people’s lives (VCSSU073)

The growth and survival of living things are affected by the physical conditions of their environment (VCSSU075)

Energy from a variety of sources can be used to generate electricity; electric circuits enable this energy to be transferred to another place and then to be transformed into another form of energy (VCSSU081)

Science Inquiry Skills

Construct and use a range of representations, including tables and graphs, to record, represent and describe observations, patterns or relationships in data (VCSIS085)

Communicate ideas and processes using evidence to develop explanations of events and phenomena and to identify simple cause-and-effect relationships (VCSIS088)

Activity Description

In this hands-on interactive STEM (Science, Technology, Engineering and Mathematics) activity, DNA is extracted from fruit. Scientific processes of DNA extraction are investigated.

You will extract DNA strands from the nucleus of plant cells and observe them. Your participation in this activity will give you experience in developing your practical, observation, reporting, and analysis skills. You will gain some biological concept knowledge, including the ability to recognize the location of cellular structures and how these can be manipulated to fulfill scientific purposes.

Grain scientists utilize these skills in their research. They undertake this process many times to obtain their data, enabling them to find out about traits of grain crops. They can then determine if they will be useful, or not and determine which grains will be used to establish the most useful and successful crops. They gain some biological concept knowledge, including the location of cellular structures and how these can be manipulated to fulfill scientific purposes.

Instructions

Materials

• DNA (Deoxyribonucleic Acid) Extraction Handout

• ½ Strawberry or Banana

• A Ziploc bags

• Soap Mixture (1 part detergent: 2 parts hot water) – dishwashing detergent such as Morning Fresh

• 1 teaspoon table salt

• ¼ cup chilled rubbing alcohol (isopropanol)

• Transparent plastic drinking cup

• Toothpick

Tune In

In this activity, participants learn the process of extracting DNA from ripe fruit. This provides them with the opportunity to see and interact with DNA.

Activity

1. Place the half strawberry in the Ziploc bag, squeeze out the air and seal the bag closed. Smash and squish the strawberry until it forms a smooth paste without any lumps.

2. Add one teaspoon of soap mixture into your strawberry mix, reseal and

3. Add ¼ teaspoon of table salt

4. Push the air out of the bag and seal shut. Squish the mixture to combine the contents and mix completely.

5. Open the bag and pour the contents into the transparent plastic cup through a muslin cloth (tea towel) as a filter.

6. With the cup containing the strawberry or banana mixture held at an angle, SLOWLY and CAREFULLY pour 40 mL of cold isopropanol down the side of the cup so that the alcohol gently floats on the mixture's surface.

7. Sit the cup down on the table. Wait for 1 minute.

8. Observe what you see happening.

9. Use your toothpick to gently spool the DNA strands.

Reflection Questions

1. Describe what you observed after the 1-minute waiting time.

2. Sketch a labelled diagram of your observations.

3. Explain what DNA stands for and what it is. Why is it so important?