By Leah Enright
Our bodies are made of 100 trillion tiny packages called cells. Each cell is like a world within itself, having many parts that work together to do the important job of keeping us alive and healthy. At the center of each cell is a special spot called a nucleus. The nucleus contains a tiny ball of skinny strands called Deoxyribonucleic Acid. DNA is important – it gives cells instructions. If your hair is blonde, red or brown, it’s because your DNA gave those instructions.
Freckles? A big smile? Thank your DNA, which was passed along to you by your parents.
People aren’t the only ones with this special ingredient. in fact, every living thing has it, from you, to that banana in the kitchen, to a giraffe in the zoo.
People did not always know about it. Many scientists worked for a long time to be able to see this mysterious molecule. Now, it is useful for solving crimes, testing food purity and helping doctors understand and treat medical problems.
We can see this special substance too. For our purposes, we’ll use common materials.
Let’s get started:
1. An adult helper
2. Three strawberries
3. 1 small zip-style freezer bag
4. 1 teaspoon salt
5. 2 teaspoons dish soap
6. 2 clear plastic cups
7. 1 coffee filter
8. ¼ Cup Rubbing Alcohol. (Place the bottle of alcohol in the freezer a few hours before using it, being sure it is clearly labeled). 91 percent alcohol is best, but 70 percent works, too.
9. 1 toothpick or skewer.
What to do:
1. Ask an adult to read through and approve this activity for you.
2. Place the strawberries in the zip style bag, and seal it. (Remove the green tops first).
3. Gently smash the berries in the bag, until they are mostly liquid, then set the bag aside.
4. In one of the plastic cups, mix 2 teaspoons detergent, 1 teaspoon salt and ½ cup of water.
5. Add two teaspoons of this liquid to the bag with the crushed berries.
6. Reseal the bag and gently mash again for a minute, then set the bag aside.
7. Tape the coffee filter onto the top of the other cup, so that you will be able to strain the berry mixture. Let the liquid flow through the filter until you have as much liquid as you can in the cup.
8. Throw the filter away, and add alcohol to your cup, by tilting the cup and letting alcohol dribble down the inside of the cup. Stop when you have about an inch of alcohol.
9. In a few minutes, you will see a white cloudy substance floating in the top of your cup. That is DNA! Use your toothpick to pick it up and examine the strands.
10. When you are finished, it is safe to wash this mixture down the drain.
When scientists examine this substance, they look at the way it is put together. Like a set of blocks, the same pieces can be assembled in different ways, to build different things. Your DNA is special and unique to you – that’s why you don’t look exactly like anyone else.
Now, you’ve seen it, but there is plenty more to learn. Check your library for books on this fascinating subject, and the next time you pass a basket of strawberries, you can say, “Hey-I’ve seen your DNA.”
Leah Enright loves children, art and science, and puts those three together as often as possible. She lives in Round Hill with her husband, children and a shaggy brown poodle named Snoopy.