DNA on Your Dining Table – Extracting DNA from Strawberries
🧬 DNA on Your Dining Table – Extracting DNA from Strawberries
You’ve eaten them in pies, smoothies, and straight out of the punnet — but have you ever seen the DNA inside a strawberry?
With a few simple household ingredients, you can make the invisible visible, and hold strands of genetic material right in your hand.
🍓 Why Strawberries?
Strawberries are ideal for DNA extraction because:
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They’re octoploid — meaning each cell has eight copies of its DNA.
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They’re soft and easy to mash, releasing cells without heavy equipment.
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They contain lots of DNA compared to many other fruits.
More DNA = more visible results.
🔬 The Science Behind the Steps
To get the DNA out, you have to:
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Break open the cells (mechanical disruption — mashing).
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Dissolve the membranes (chemical disruption with soap).
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Remove proteins that are bound to the DNA (using salt).
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Make DNA clump together (by adding cold alcohol).
🥼 What You’ll Need
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2–3 ripe strawberries
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A zip-lock bag
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A splash of washing-up liquid
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A pinch of table salt
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Water
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Coffee filter or kitchen paper
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A clear glass
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Cold surgical spirit or isopropyl alcohol (chilled in freezer)
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A wooden stir stick or skewer
🧪 Step-by-Step
1. Mash the Strawberries
Place the strawberries in the bag, squeeze out the air, and mash until you have a pulpy mix. This breaks open the cell walls.
2. Add Extraction Solution
Mix a little water, washing-up liquid, and salt. Pour into the bag, seal, and gently massage.
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Soap dissolves the fatty cell membranes.
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Salt breaks up protein–DNA complexes.
3. Filter the Mixture
Pour the contents through a coffee filter into a glass. This separates solids from the liquid containing the DNA.
4. Add Cold Alcohol
Gently pour cold alcohol down the side of the glass so it forms a layer on top. DNA is not soluble in alcohol — it will precipitate.
5. Watch the DNA Appear
White, stringy clumps will form at the alcohol–liquid boundary. Use the skewer to spool them out.
🔍 What You’re Looking At
That white, tangled mess?
It’s the blueprint of life — the same code found in nearly every living organism. In strawberries, these strands contain the instructions for making seeds, leaves, roots, and fruit.
🧠 Extending the Experiment
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Try other fruits — bananas, kiwis, grapes — and compare the DNA yield.
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Use a magnifying glass or a microscope to look at the strands up close.
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For older students, discuss how DNA extraction is used in genetics, forensics, and medicine.
📚 Teaching Note
This practical is perfect for GCSE Biology (cell structure, DNA, genetic material) and A-Level Biology (nucleic acids, extraction techniques).
It’s low-cost, safe, and gives students that instant “wow” moment.
At Philip M Russell Ltd, we bring science to life — whether it’s in the lab, classroom, or online. Experiments like this don’t just teach; they inspire curiosity.
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