9 replies to this topic

[Maddie]

Hi everyone,

For those who have kids (or look after kids), here is a little experiment I found on the net that you can do easily with your kid, in your own kitchen: how to extract DNA from strawberries. Yes! How cool is that?
Why strawberries? here is what they say:
"Why use strawberries to test your DNA extraction kit? Because strawberry cells each have eight copies of the genome in every cell! When an organism has eight copies, called an octoploid, it has a lot more DNA per cell than an organism that only has one copy. Using DNA from strawberries will help you have a successful DNA preparation so you can purify a lot of DNA."
I'm learning everyday  



Here we go:

Materials and Equipment
• Measuring cup
• Measuring spoons
• Rubbing alcohol  (looks like it's isopropanol)
• 1/2 teaspoon salt
• 1/3 cup water
• 1 tablespoon dishwashing detergent (Dawn®)
• Glass or small bowl
• Cheesecloth
• Funnel
• Tall drinking glass
• 3 strawberries (green tops removed)
• Resealable plastic sandwich bags
• Test tube or small glass jar (e.g., spice jar)
• Bamboo skewer (find them at the grocery store)

Experimental Procedure
1. Chill the rubbing alcohol in the freezer. (You'll need it later.)
2. Mix the salt, water, and Dawn detergent in a glass or small bowl. Set the mixture aside. This is your extraction liquid.
3. Line the funnel with the cheesecloth, and put the funnel's tube into the glass.
4. Put the strawberries in the plastic bag and push out all the extra air. Seal it tightly.
5. With your fingers, squeeze and smash the strawberry mixture for 2 minutes.
6. Add 3 tablespoons of the extraction liquid you made in Step 2 to the strawberries in the bag. Push out all the extra air and reseal the bag.
7. Squeeze the strawberry mixture with your fingers for 1 minute.
8. Pour the strawberry mixture from the bag into the funnel. Let it drip into the glass until there is no liquid left in the funnel.
9. Throw away the cheesecloth and the strawberry pulp inside. Pour the contents of the glass into the test tube or small glass jar so it is 1/4 full.
10. Tilt the test tube or jar and very slowly pour the cold rubbing alcohol down the side. The alcohol should form a layer on top of the strawberry liquid. (Don't let the alcohol and strawberry liquid mix. The DNA collects between the two layers!)
11. Dip the bamboo skewer into the test tube where the alcohol and strawberry layers meet. Pull up the skewer. The whitish, stringy stuff is DNA containing strawberry genes!

Variations
You can try these steps to purify DNA from lots of other living things. Grab some oatmeal or kiwis from the kitchen and try it again! Which foods give you the most DNA?


More there:http://www.sciencebuddies.org/science-fair-projects/usasef.shtml?ph=1

[gebirgsziege]

did this once with a class in elementary school: used tomatoes back then, because the DNA keeps some red color....kids loved it  

[Maddie]

gebirgsziege, on 21 October 2010 - 09:52 PM, said:

did this once with a class in elementary school: used tomatoes back then, because the DNA keeps some red color....kids loved it  

Ouhhh, we may try tomatoes after strawberrie then  
Do you know any other fun stuff to do? My son's in 2nd grade.

[pDNA]

Try this one ...its rahter funny ...since you can drink your DNA after isolation (maybe not the right experiment for kids

Regards,
p

[gebirgsziege]

which kind of experiments are you interested in only molecular biology?

[Maddie]

gebirgsziege, on 24 October 2010 - 10:37 PM, said:

which kind of experiments are you interested in only molecular biology?

well, not really but I suck at physics  

[Maddie]

pDNA, on 22 October 2010 - 08:42 AM, said:

Try this one ...its rahter funny ...since you can drink your DNA after isolation (maybe not the right experiment for kids

Regards,
p

  thanks pDNA. I think I will try..but I doubt I will drink it  

[Maddie]

Maddie, on 27 October 2010 - 03:02 PM, said:

pDNA, on 22 October 2010 - 08:42 AM, said:

Try this one ...its rahter funny ...since you can drink your DNA after isolation (maybe not the right experiment for kids

Regards,
p

  thanks pDNA. I think I will try..but I doubt I will drink it  

Darn, you gotta be a member to get the pdf. Would you have it by any chance?  

[bob1]

How about chemistry?  You can make silly putty as below:

Silly Putty Recipe

    * solution of 55% Elmer's glue solution in water
    * solution of 16% sodium borate (Borax) in water
    * food coloring (optional)
    * Ziploc bags

Mix together 4 parts of the glue solution with one part of the borax solution. Add food coloring, if desired. Refrigerate the mixture in the sealed bag when not in use.

[Maddie]

bob1, on 27 October 2010 - 03:17 PM, said:

How about chemistry?  You can make silly putty as below:

Silly Putty Recipe

    * solution of 55% Elmer's glue solution in water
    * solution of 16% sodium borate (Borax) in water
    * food coloring (optional)
    * Ziploc bags

Mix together 4 parts of the glue solution with one part of the borax solution. Add food coloring, if desired. Refrigerate the mixture in the sealed bag when not in use.

oh I don't know a kid who doesn't like silly putty  
Where do you buy the glue and borax?