admin answers:

Heh. I just did some DNA extraction at home.

Gimme a minute (ok, more like 30 minutes) and I can give you a link to a recipe for DNA extraction.

But first I want to test it on the onion. (works great on a strawberry!)

Edit:
does it have to be an onion? Can it be a strawberry? Please respond.

================================

It works really well on a strawberry, but it works on an onion as well.

What you will need:
•zip lock bag
•NON-iodized salt (No Iodide. It’s in the grocery store, too.)
•some good liquid, grease breaking dish washing soap
•distilled water (get some bottled water. Read the label. If you can’t find some that says that it is distilled, look for filtered. If you can’t find some that says filtered, just get some bottled water. The distilled and filtered part is to keep out any microbes. You want onion DNA not microbial DNA.)
•ice cold 90% or higher Isopropyl Alcohol (the poisonous kind. It can also be found in the grocery store)

•a thin slice of a small onion, or use an average sized strawberry.

•a knife for the onion (a blender is better!), nothing for the strawberry

•a coffee filter or paper towel

•a very small cup or glass that you can see down into really well.

=====================

put the alcohol in the freezer to make it cold.

Mince the onion. Chop it as finely as you can get it. (or blend it into a liquid). Just rip apart the strawberry

put it into the zip lock bag.

Put a couple of pinches of salt on the onion in the bag.

Drop a few drop of the liquid soap on the onion.

Pour in about 4 tablespoons of the water.

Seal the bag.

Mash the onion pulp (or strawberry) repeatedly with the flat side of the knife to further break down the onion.
(Don’t break the bag)

mash it really well.

Once it is essentially salty, soapy, onion/strawberry soup, hold the bag up so the liquid runs to the bottom of the bag in 1 corner.

Cut the top corner off (leave a small enough hole so that the big stuff is kept in the bag and the soupy mixture can leave)

pour the mixture through the coffee filter or paper towel and into the cup.

Take the alcohol out of the freezer

very, very, very carefully and very, very, very slowly pour the alcohol slowly down the side of the cup and try to get it to float on top of the mixture. There should be the mixture on the bottom and alcohol floating on the top. Just to give an idea, you can add about as much alcohol as water. You can get away with less, but you do need enough of a layer of alcohol on top so that there is a region for the DNA to move into so you can see it.

Let it sit for a few minutes.

Slowly the DNA will be released from the cells and will go up into the alcohol.

The DNA will be stringy white stuff. You can’t miss it.

admin answers:

Http://www.mnsu.edu/emuseum/information/biography/abcde/crick_francis.html

There is the whole story.
X-ray diffraction.

admin answers:

Styrofoam balls ARE handy to use since you can put toothpicks in them, but I can see your point that everybody else already uses them.

There are lot of websites how to build DNA models from e.g. Candy or beads, but those models obviously won’t be able to reach 3 feet high, nor stand by themselves. So you got to use something relatively big, sturdy, yet something you can stick toothpicks or skewers in…
Here are some pictures of examples, you can still vary a lot with styrofoam:

http://www.elysciencecenter.com/biology_i_honors/biology_pre-ap_mini-project_dna

Here is a website that explains how to make it from cardboard. It might not sound too exiting, but it will give you a very accurate model, which might please the teacher…. You can color the parts and still make it look creative.

Http://www.starsandseas.com/SAS%20Cells/DNA%20Replication/dnarepli_modelprt.htm

If you have a little brother or sister (or neighbor) you could also build it from Duplo (big Lego) blocks. Will be pretty sturdy and colorful, but you will need a lot of blocks to reach 1 feet, so you might need to borrow blocks from the whole street…

This website tells you about how to build a DNA model from Lego Technic blocks:

http://www.ehow.com/how_6217810_build-3d-lego-dna-model.html

Good luck!

admin answers:

Pretzels and gum drops, in different colors.

admin answers:

This time of year you might be able to find chocolate covered candy sticks, but they won’t be as thin as a toothpick. If you want to keep it edible you can try using uncooked spaghetti or pretzel sticks (not rods). You can even cover the sticks in chocolate!