Tuesday, March 20, 2012

Dynamic DNA

This week we're doing an experiment with DNA! Now doesn't that sound exciting? In this lab you will be able to see the very small DNA from a cheek cell or from inside a pea. The procedures for cheek cells and peas are a little different, so make sure you read the instructions.

If you have access to a microscope we suggest you take a look at the cells in your mouth.
1.) Place a drop of iodine on a microscope slide.
2.) Take a toothpick and gently scrape the inside of your cheek.
3.) Place the toothpick in the iodine and swirl.
4.) Start with low power (4x) and look at your cheek cells!
Now that you have a general idea of what your cheek cells look like try this experiment.

- Spilt Peas, Strawberries or any other DNA source (if not using cheek cells)
- Blender
- Salt
- Water
- Measuring cups
- Test tubes
- Dish soap
- Contact Solution (meat tenderizer or pineapple juice)
- Rubbing alcohol (isopropyl or ethanol)
- Glass stirring rod (wood skewer or Q-tip)

Cheek Cells
1.) Swish salt water in your mouth for 30 seconds. (This is a long time, but you can do it!)
2.) Spit the water into a cup, then pour it into a large test tube.
3.) Add 1 teaspoon of dish soap to the large test tube.
4.) Gently shake the test tube. (If you do this in a beaker or cup, gently stir the cup)
5.) Pour about 1 teaspoon of alcohol into the tube.
The best way to do this is by tilting the test tube and slowing pouring the alcohol.
Ideally there will be a small layer of alcohol above the soapy mixture.
6.) Using the glass stirring rod - twirl in one direction to collect the DNA

Split Peas & Other Foods:
1.) In a blender add and blend on high for 15 seconds:
- 1/2 cup split peas
- 1/8 teaspoon table salt
- 1 cup water
2.) Pour the pea mixture through a strainer (you want the liquid) and let sit for 5-10 minutes
3.) Pour some of the liquid into a test tube
4.) Add 1 teaspoon dish soap to the large test tube
5.) Add some contact solution to the test tube 
(you don't need a lot, a small squirt or a pinch for tenderizer)
6.) Add about 1 teaspoon of alcohol to the test tube
Just like the cheek cells you want a layer of alcohol above the soapy pea mixture
7.) Using the glass stirring rod - twirl in one direction to collect the DNA

You can save this DNA or look at it on a wet slide under a microscope.
To save: Put the DNA in a small test tube or container with some alcohol.

(Pictures for the steps to come)

Further information:

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