Jelly Bean Heredity

Last year when I was looking for a lab activity to help my students understand the basics of Mendelian Genetics I came across the hands-on activity, Heredity Mix and Match on teachengineering.org.

In my Advanced Life Science class last week we made jelly bean babies. In this lab investigation we're working on distinguishing genotypes from phenotypes and how they are interconnected. We also had discussions about being homozygous and heterozygous for a trait, and even squeezed in a few Punnet squares with a review of dominant and recessive genes. All the students enjoy naming their newly created baby and parents-even the ones I would have never guess would get into it.

I reformatted the Heredity Mix and Match from teachengineering.org into a Google Doc with a just a few minor changes.

Restriction Enzymes and Washi Tape

We're going to do the gel electrophoresis lab in AP Biology this coming week. I love for students to have a visual of what is happening when we get DNA ready for electrophoresis. This visual also helps them as we discuss why some pieces of DNA move faster than others and therefore give us distinct bands.

For our pre-lab conceptual practice we use toilet paper to represent DNA, washi tape to represent the location of specific palindromic restriction sites, and scissors labeled with specific washi tape to represent the restriction enzymes. Students take turns using the restriction enzymes to cut the DNA and then we determine the number and placement of bands on a gel using the number of toilet paper squares that are in each cut piece of DNA. The idea for this came this video on Vimeo.

 

For students to represent their electrophoresis gels, I made a template in Google Slides that I can project onto the whiteboard in the classroom.  Students can mark where they think the toilet paper DNA will migrate to.  Then I switch to the second slide that will reveal the banding pattern of the "criminal".  I like to wait to show that until last, otherwise they figure out who the criminal is before they finish getting all the bands up.  This way, the suspense lasts until all the bands are drawn on the board.

The template in Google Slides also includes the sketch of locations of each of the restriction sites.

Genetic Advances and Ethics

As we are finishing up our unit on molecular genetics, our ethics project is coming up. Last year I had them write a position paper on GMOs, but there are so many genetic advances, I didn't want to limit them. Several advances have been making the news from CRISPER-Cas 9 to the three parent baby (mitochondrial transfer).

Going along with the seminar our school just had on making assignments relevant to students and teaching them skills that they will have even after they have forgotten the content of the class, I decided to change the assignment. Now they will have more choice. Students may chose what genetic advance they want to talk about and may also chose how they will present their views. It won't be an informational report, but a report on what they think about these advances, what issues these advances bring up, and what role they can play in making their voice heard about those issues. As these "nearly adults" are about to be launched into the world, I hope they will feel empowered to make the world a better place.

Here's the project document for the students.

Revising Transcription and Translation for AP Biology

I just finished the Transcription/Translation Lab from Kim Foglia with my AP Bio class.  Last year when we did it, we decided that there was too much cutting and taping involved and not enough time being able to keep our eyes on the concepts.  This year, I gave lab groups only half of the DNA strip and then we put our DNA strands together.  This was a huge time saver.  It also helped that I laminated and cut out all of the RNA nucleotides, so the students didn't have to do it (and ideally, I won't have to do it again either). We completed the translation process together.  Then the students went back into their groups and worked through each of the mutation sections.  But I still felt like it took far too long. Next year, I'll assign a different mutation to each group and then have them explain/demonstrate the effects to the rest of the class.

For extra practice going through the process of transcription and translation, we'll add a little competition and have transcription/translation races.  The "proteins" built will be sayings, with words substituted in for the amino acids. The idea came from doing the Foglia lab and seeing a pin on Pinterest of a product by AwesomeScience. I googled 5 word sayings and found several interesting ones at http://www.lifestalker.com/21-simple-yet-powerful-five-word-quotes/ and http://hubpages.com/education/5-word-quotes.  At first I though I'd make my own tRNA molecules so everything would be typed.  As much as I love Google Drawings, a few minutes in, I decided instead to use Foglia's blank tRNA molecules and write the words and anti-codons in myself. I laminated them in hopes that I wouldn't have to do it again.

The tRNA molecules are placed on a table at the front of the room, and as students finish transcription and are in the process of translation, they come up and chose one tRNA molecule at a time that complements the mRNA strand they've made. Students actually have a full sheet of paper to write in their transcription and translation and also answer a few questions to highlight some of the important, but often forgotten nuances of transcription and translation.

Here is the link to the modified Kim Foglia Transcription and Translation Lab. And here is the link to the Transcription Translation Races. For this document, the answer key is first and then each of the following pages is for each of the 7 different sayings. I think I caught all of my typos in the DNA strands, but if I missed one, let me know.

DNA Replication "Like a Pirate"

Last year as I was looking for ideas to help my students understand the process of DNA replication, I found a blog post by Chi Klein titled Trouble with Lagging Strands. Chi had used two long pieces of butcher paper with traced footsteps to make a larger than life model of an opened stretch of DNA.  I loved the idea and found some butcher paper and made my own.  It took a long time to make, so I decided to laminate the sheets to help them last longer.  Unfortunately, the paper was a few inches wider than our school's laminator.  Out came the clear contact paper. I've used at least 4 rolls and it isn't completely covered, but it's pretty close.

I just got the book, Teach Like a Pirate by David Burgess and decided to give teaching like a pirate a try for this lesson. I made these signs to post outside my classroom to generate some curiosity and get them prepared for "walking" through DNA replication.

Chubby Checkers (The Twist) was playing in the classroom and they had a time limit to be ready to go (and a treat for accomplishing it).  Students had to be creative about finding a place to sit since the desks had to be pushed together to make room for our DNA.

Each student received an enzymatic role to play in the process of DNA replication.  We emphasized the anti-parallel nature of DNA and only building in the 5' to 3' direction, which led to discussions of the lagging strand and Okasaki fragments.  Now we'll see how the quizzes that they take tonight go.

One other bonus...I have these twisted silver earrings that make me think of DNA every time I wear them.  I donned the earrings this morning, as well as a sweater with a twisted knit pattern on the front. Near the end of class, one of my students commented that my earrings looked like DNA. I had forgotten to mention it, but then pointed out my "DNA" sweater as well for some chuckles.

Unit 7 Reading Guides--Evolution

Since I've finished planning out our Molecular Genetics unit, it's time to start working on the Evolution Unit.  Here are the guided reading questions for the chapters in this unit.

Chapter 22-Descent with Modification
Chapter 23-The Evolution of Populations
Chapter 24-The Origin of Species
Chapter 25-The History of Life on Earth
Chapter 26-Phylogeny and the Tree of Life
Chapter 27-Bacteria and Archaea