DNA

 For whatever reason, kiddos feel as though they are doing science when they make DNA models.  Why?  I have no idea.  But, let’s capitalize on their interest.  Before you buy a model, let me share a few hands-on activities. Does your library have a 3D printer?  Do you have loads of time?  Look at the Folding DNA Model Kit at Thingaverse.

1.  Extract DNA. Use split peas.  Be sure to have fresh meat tenderizer.  Otherwise any detergent or variety of alcohol seem to work.  The Strawberry DNA Extraction does not require meat tenderizer—just expensive strawberries.

2. DNA Keychains and DNA Bead Necklace can appeal to your crafter.  Use can use pipe cleaners and beads, too.

3. Fold Your Own DNA, Make a DNA Model with construction paper and toothpicks.

4. HHMI Interactive Model, Modeling the Structure of DNA, the student hand-out, and copy of nucleotides is a mini-course in DNA.

5.  DNA Pop Beads, Modeling DNA with Pop Beads, or Building DNA with Beads all use pop beads.

6. Candy DNA (gum drops), Edible DNA (marshmallows), and Make a DNA Model with Gummy Bears and Candy.  Save this model for last.

7. DNA Paper Model is cheap to make.  This cardboard model is quite elegant.

You can always just buy a model.  This one was about $9.  I just had to know what quality of kit I could get to use as a demo.  

Below are some more commercial kits.

Teach DNA and RNA

DNA is an abstract topic to teach.  I like to start with a lab.  The Apologia textbooks have DNA extractions in Module 6 (third edition) and Module 7 (first and second edition).  Here are instructions for extracting DNA from anything.  I use split peas—because they are cheap.  Extract DNA so the kids have something tangible to wrap their heads around.  I think Carolina Biological had the original idea for DNA Necklaces.  Here are free instructions. Personally, I’m not wild about wearing something I made in lab around my neck.  Hey, your teen might like the idea.  

Get started making models.  Start with Edible DNA.  Next create a Paper Model of DNA.  Color the nucleotides adenine, guanine, thymine, and cytosine and make a key.  Next I do DNA replication with paper clips.  Note the colors of the paper clips.  I recommend using those colors for the paper DNA model, too.  The paper clip replication takes some time, especially to answer the questions.  Go back to paper for Transcription and Translation or Protein Synthesis.  Note the links for all of the patterns.  These models require an investment of time.  After each activity, stop and process.  This slideshow has basic information about DNA, nucleotides, replication, transcription, and translation.  Use the textbook, too.  Take it slowly, make loads of models, read the textbook, and invest some time processing.  What is DNA?  How does it copy itself?  What is DNA to RNA replication?  How does RNA transcribe the message and translate it into proteins.  Amazon has the DNA model kit featured below, which I believe I assembled upside down.  Deep breath!  You can do this!

Apologia Biology: DNA Nucleotides Complete

Where are we now?  We are in the throes of tax season and Co-op.  Now that it is April, we've been trying to complete DNA before Botany and the dissection.  After Genetics, we went back to finish DNA.  

First, we built amino acids and nucleotides with the Lab Aid Biomolecules Kits.  The kids also build DNA and Transcription with Lab Aid Models of DNA and Transcription.  (The carbons in the kit tend to break during Replication.  I sent copies of my purchase order and photos of broken carbons to Lab Aids.  They sent back several dozen replacements.  The Biomolecule kits are much sturdier.  I've used my older kit for years without breakage.)  The kits come with excellent worksheets.  The instructions have the kids build the molecules and answer questions.  

Homework included a transcription translation coloring sheet.  Next, the kids do this DNA puzzle piece activity using these templates.  Make loads of copies of each of the three templates.  The first step is to use the DNA pieces (four or five) to demonstrate DNA replication.  Next, one uses both DNA and RNA pieces to model transcription.  Finally, the same RNA sequence (mRNA) is copied to tRNA.  The idea is to understand A-T or A-U and G-C (Nucleotide base pairs)  This takes awhile.  Once the kids have these models, they use a DNA strand to make a double helix, mRNA, and tRNA with pipe cleaners (chenille sticks) and pony beads.

This transcription translation worksheet is my final quiz.  I used the DNA strand for the bead activity.  Lastly, the kids write paragraphs explaining the differences between DNA and RNA, describe Replication, Transcription, and Translation, including the location.  (I emphasize that DNA Replication occurs in the nucleus during mitosis as part of the cell cycle.  Transcription also occurs in the nucleus.  Translation is in the cytoplasm at the ribosome.)  The kids also explain codons and anticodons.  Whew!  Next week we start plants.  See below our photos.

Apologia Biology: DNA Extraction Lab

Update: The last photo has a decent shot of the DNA.  It is white threads which float into the alcohol.

Update:  This week (after Thanksgiving) we're doing the DNA lab.  Yesterday's class went as expected.  The girls extracted mounds of DNA; the boys all need to try again.  See pix below.
Tomorrow, we're doing the DNA extraction lab with split peas--the instructions are in the Apologia textbooks.  (The first edition uses onions instead of split peas.  The link has directions for extracting DNA from just about anything.)  The key is to use fresh meat tenderizer.  My class is doing the lab as an inquiry project.  I bought three types of alcohol: denatured ethanol, and two different percentages of isopropyl or rubbing alcohol.  I also bought salt with and without iodine.  My materials include two brands of dish detergent, shampoo, and hand soap (clear).  The students will hypothesize which factor produces the most DNA.  (Remember, it's fresh meat tenderizer.)  The kids are going to test the different types of alcohol, salt, and detergent.  So, they'll do a number of trials.  I expect to take two class periods to do the lab; the kids will write another formal written lab report.  Here is my plan.

1.  Explain how to extract DNA and distribute lab instructions.  Our class will use 50 grams of split peas, 100 mL of cold water, two grams of salt, 15 mL of soap or detergent, and one gram of meat tenderizer.  The kids may need to adjust these measures.  I want the kids to weigh with a digital scale and measure volume with graduated cylinders instead of using cups and teaspoons, which are cooking measures.

2.  The next step is for each lab group to form a two-part hypothesis.  Here is an example.
    Null Hypothesis:  The type of detergent will have no effect on the amount of DNA produced.
    Alternative Hypothesis: Dawn dish soap will produce more DNA than Gain dish soap.

3.  Each group must identify controls and take note of the materials the group uses.

4.  Each group will perform at least three trials with different independent variables.  The groups chose which variable to test: alcohol, soap, or salt.


When I first did DNA extraction labs, I used expensive kits, chilled the alcohols,  used only ethanol, and timed each step precisely.  The kids may compare chilled alcohols to room-temperature alcohol.  This lab is usually a favorite.  I'll post pix this week.

Cheap and Easy DNA Models

 By all means, make a DNA model. My Biology classes make several models.  It really helps kids understand the components in DNA.   Here are step by step instructions to make a DNA model with construction paper and toothpicks.  My kids make Licorice and Marshmallow DNA Models, Origami DNA Models, Paper Models, and work through the Lab-aids DNA & Nucleotide Modeling activity.  (This kit is not cheap.  I invested in a set because I teach Biology regularly.) you will not be short changing your teen if you only do one or two paper models.  Be sure to color them! I completely forgot we made  DNA models with beads and pipe cleaners until I ran across the photo.  The photos below are examples of the DNA models. The first model I bought from Amazon, currently priced at $9, is flimsy.  Just make your own.

Apologia Biology: DNA

The kids took their test.  The good news is that no one cheated.  We're retesting on Tuesday.  After the test, we worked on DNA replication.  We used two set of the Lab Aids DNA and Replication kits.  (The ribose molecules broke off easily.  I sent photos to Lab Aids to see if I can get replacement parts.  I'll let you know.)  (You may recall I used Lab Aids Modeling Molecules of Life earlier for Biochemistry.)  We worked through building the DNA molecules and DNA replication.  Next, we're building nucleotides and amino acids before tackling transcription and translation.  These molecule kits are pricey--I hope to teach Biology again and will use these models again.  Teach Genetics has a hands-on activity for transcription and translation.  I've used this paper clip activity for DNA replication, transcription, and translation.  The kids are going to work through this activity using these DNA and RNA templates.

Below are photos of the DNA models and DNA replication.  Next week, I'll post pix of the amino acids and proteins--and possibly the four nucleotides.

On a Quest!

 The Bio class is tackling DNA replication, transcription, and translation, Module 7 in Apologia Biology.  DNA codes for proteins.  The processes of replication, transcription, and translation or protein synthesis are very confusing.  So, I’m on a quest for models.  The kids are completing DNA models, paper models, and DNA templates.  You can make models with pipe cleaners: Make a DNA Model, Bio Bracelets, and How to Make a Model of DNA…, How about DNA Replication with Paper Clips?  I’ve used this activity with four colors of paper clips; the kids were confused.  Teens find the bead models less confusing.  Here is a top for hands-on models.  Ask the kids to explain the model.  What does the red bead represent?  Which nucleotide is A?  Differentiate between nucleic acids and nucleotides.  Explain in words how DNA replicates or copies itself.  How are DNA and RNA different?  Remember, the model is teaching a process.

DNA Sentences

 We’re just starting DNA.  But, last year I tried DNA sentences.  Wow!  They helped enormously!  Kids struggle with the difference between replicated DNA, transcribing DNA to RNA, coding into amino acids.  The kids decode words and create sentences.  Here is the one I’m using first.  There are many, many DNA sentence activities: Say it with DNA, Protein Synthesis Sentence Activity, or Spell Your Name in DNA.  Once kids have the process, then go back and instruct in the specifics for replication, transcription, and translation.  I know this sounds backwards.  But, if they have the overall concept, the rest is just details.

Apologia Biology: DNA Transcription and Translation Module 7

I'm a stickler for kids to understand the process of DNA transcription and translation.  Actually, we already extracted DNA and did some preliminary genetics.  I like to wait to review transcription and translation.  First, they made a paper DNA model. (Here are photos.) Once they finished the models, we reviewed the process, labeled nucleotides, purines, pyridimines, codon, anticodons, and peptide chains.  The girls took turn orally reviewing the process and finally wrote a summary paragraph as an assessment.  I used this DNA replication site to explain leading and lagging strands, etc., but didn't require them to memorize Okazaki fragments.  Yes, this takes time.  Almost six hours! As the kids write their paragraphs, I have them elaborate and differentiate between the DNA and RNA molecules.  Details matter!

Update!  Check out these DNA bracelets!  You can code your name in a DNA bracelet!

DNA Activities

 This post has more DNA activities.  Once the kids make the Twizzler DNA models and complete the DNA Lab-aids models, they are doing RNA Transcription with these templates from Nancy Clark’s DNA Collection of activities.  I’ll post pix next week.  Keep in mind the kids are doing DNA and RNA transcription several ways, including DNA Sentences.  DNA replication, transcription, and protein synthesis are tough topics.  Start with models-lots of them!

DNA Extraction

Update:  We had the best results using 90% isopropyl alcohol, Dawn detergent, and iodized salt.  BTW, I keep my DNA supplies in a kit.  The meat tenderizer is supposed to be good for a year.  I’ll check next year when I teach Bio again.

Today, the Bio class is extracting DNA.  Here are instructions to extract DNA from just about anything.  The key is to use fresh meat tenderizer.  We use split peas.  Additionally, this lab is more inquiry-based.  I have two types of dish soap and different percentages of alcohol.  When I have a large group I add ionized salt vs sea salt, rubbing alcohol vs ethyl alcohol, and chilled vs room-temperature alcohol.  The kids can form a hypothesis.  For example, one group might hypothesize that sea salt will produce more DNA than iodized salt or chilled ethanol may produce more DNA than room-temperature ethanol.  My kids are using this lab for their third, formal lab report since they need to write at least four for several online schools to receive lab credit.  This lab might take two class periods to complete because kids need to perform two tests for each trial.  The white threads on top of the pea solution are DNA.