100 Days of science #89, 90, & 91- DNA Experiments

We studied quite a bit about DNA this year and I could not believe it when I realized that we had totally forgotten to do these fun DNA experiments I had picked out!  I decided there was not time like the present and gathered all the materials we needed. 



Before starting any of the experiments I did ask the boys to tell me everything they could remember about DNA and I was pleasantly surprised at all that they had retained from our readings.  We quickly moved onto the experiments. 


First we did a strawberry DNA extraction.   

Using a strawberry, some rubbing alcohol, water, and dish soap we were able to extract (a few!) DNA strands from the strawberry.  


We put our rubbing alcohol in the freezer for about 20 minutes; it needs to be cold to work properly.

Meanwhile in a small glass we combined 6 Tablespoons of tap water with 2 tsp. of dish soap and just a pinch of salt.



With our solution all ready to go we set it aside and began working on smooshing up our strawberry.  We put it in a Ziploc bag and used our fingers to  break it into fine pieces; making sure to keep most of the strawberry at the bottom of the bag.


We added our soap/water solution to the bag and mixed it around a bit.



Using an empty glass we rubber-banded a piece of paper towel over the opening and made a well in the center to catch all our strawberry mess. Any sort of mesh strainer would work too.  You just want to collect some of the strawberry juices in the bottom of the glass.


To that juice you'll add a bit of the cold alcohol.  Since we were using a small glass I poured enough alcohol to reach mid-way up the glass but you're really just looking for long strands to separate from the juices and float up into the alcohol--- those strands are your DNA!


We use a toothpick to scoop some up... they look a bit like pink boogers (not gonna lie that is what all three of my boys compared them to and they're right!).


We scooped up a second batch of DNA and added it to a test tube of alcohol we had prepared; just to watch it float around and see what it would do.



Second, we took a strand of DNA and put it on a microscope slide.  We tried looked at our strand of DNA under the microscope.  Now we knew we would never see the double helix that all the books show since you need a very, very powerful microscope to do that but we still wanted to see what it would look like anyway!




We hypothesized that the circles are where the soap bubbles were and all the lines around it are most likely DNA strands. 


Finally, we used gumdrops, toothpicks, and twizzles to make our own model DNA strand. 

First we separated our gumdrops by color and I had each boy pick 4 colors they were going to use on the whole strand.  


Then I had them assign each color to one of the DNA bases: Thymine, Adenine, Guanine, and Cytosine. (which they all labeled as T, A, G, C).

We talked about how the T&A always pair together and the G&C always pair together but that using just these two pairings there are infinite numbers of ways that DNA strands are combined... Then I let them go to work and make their own.




Their finished products were quite colorful and the only thing I made sure of was that the color pairing always matched up.






They had lots of fun eating the Twizzlers and sampling all the gumdrops too.


Others in this series:
58.  Exploding Snow and Water Baggies 
59.  Exploring Properties of Minerals
60.  Visiting the Hartford Science Museum
61- 63.  3 Difference Bridge Challenges
64.  Making Models of the Earth's Layers 
65.  Graham Cracker Plate Tectonics 
66.  Homemade Lava Lamps
67.  Movies We're Watching for Science
68.  Index Card Tower Challenge 
69.  Learning Botany at the Botanical Gardens
70.  Board Games for Science
71.  Homemade Frozen Yogurt Pops
72.  Starburst Rock Cycle 
73.  & 74.  Making Marshmallows Sink and Grow
75. Jumping Conversation Hearts
76-78.  Making Paper Airplanes 3 Different Ways 
79.  Learning About Hummingbirds
80.  Planting an Herb Garden
81.  Mushroom Spores
82.-84.  Penny Saturation Experiment
85.  Sink or Float?
86.  Disappearing and Re-Appearing Ink
87.  Sediment Layer Jars 
88.  Tie Dye Science 

Comments

  1. Nothing like candy to heighten a guy's interest in science!

    ReplyDelete
    Replies
    1. Exactly! I know if it involves food my boys are all for it.

      Delete
  2. What great experiments! My little scientist will love doing these as well.

    ReplyDelete
    Replies
    1. You just can't go wrong with hands on science experiments and if there's an edible component that makes them even better.

      Delete
  3. Haha! You certainly can't go wrong with a fun science experiment that involves food!

    My son is now pursing his masters in microbiology and he said it was because of fun experiments we did like this that piqued his interest.

    ReplyDelete

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