Mendelian Genetics with Fastplants, Corn on the Cob, and Sickle Cell Anemia

We've been increasing our repertoire of labs that students can do as we're talking about Mendelian and non-Mendelian genetics.

One of the labs that we've done for two years now is with Fastplants. This is another lab I use from Lee Ferguson and is on her website here under the Mendelian genetics link. Since I have small classes, I only buy one set of F2 seeds and all of the lab groups germinate the same type of seeds. Then we pool all of our data to analyze it. Last year, we used the F2 crosses of purple vs. green stems, and green vs. yellow leaves. We had a terrible time distinguishing the color of leaves since purple stems make the yellow leaves look greener, and green stems make the green leaves look lighter. Although we had great germination rates, our ratios were not even close to the expected. In our class discussion of our results, we decided it was due to the difficulty in distinguishing leaf color.

This year, I decided to go with green vs. purple stem and dwarf vs. normal height. My students were pretty excited about how well the seeds germinated and how as they sorted them by phenotype how close the numbers were to the expected values. They were pretty stoked about how small their chi-squared value was for our class data. I love it when they get excited about this kind of stuff! I think part of it is that they often complete labs with fairly high percent errors, and it's actually satisfying for results to go so well. They all agreed that this was a great variety of seeds to analyze. I'll be ordering this variety again next year.

Another lab that allows us to look at the ratio of phenotypes in a dihybrid cross involves looking at ears of corn. I went to an APSI this summer and one of the labs that I won was a class set of ears of corn from a dihybrid cross involving yellow vs. purple and smooth vs. wrinkled.

The lab we use to analyze the ears is from Biologycorner.com and you can find it here.

Another activity that I've added to our genetics unit is from HHMI Biointeractive. We do the activity titled Mendelian Genetics, Probability, Pedigree, and Chi-Square Statistics and the teacher and student materials can be found here. We watch the short film first, that is also found on that page, and move onto the questions. I like the introduction to sickle cell anemia since we'll revisit it when we get to the natural selection unit. 

Question Stacks in Precalculus

This year, I returned to teaching full time as I took on a Precalculus class. I have loved being back in the math classroom. I still teach AP and Honors Biology, but am excited to be doing some math as well.

Since I hadn't taught Precalculus in 21 years, I found a pre-made curriculum that was highly rated and to my delight, my school purchased the curriculum from All Things Algebra on Teachers Pay Teachers. I have been busy making activities to go along with the class, but I often use the questions from Gina's curriculum so that the activities fit well with the pre-made notes and homework that the students have. Alas, I can't share those activities with copyrighted information.

One of the activities that I have students do are question stacks. I love that they are self checking. I had read about them at the Math Equals Love blog here. Sarah provides a blank master copy to make them that work with printable business cards. I have loved using the business cards because I can just print, pop them out, and they are ready to go, no cutting needed.

So that I could share something, I went ahead and made a question stack for expanding and condensing logarithmic expressions using questions that weren't part of the curriculum. You can find the question stack here. Although it is in Word format, you should be able to open it as a google doc and it should work fine...at least it does for me.

Onion Mitosis Lab

One of the labs that I've come to enjoy while we are studying the cell cycle in AP Biology is the Onion Mitosis lab. I love this version of the lab because it requires very little prep time on my part, and within a week, my students have some real data to analyze. The lab I use with my students was modified from Lee Ferguson and can be found on her website, The Biology Space, here under the cell structure and function resources. 

It's hard to see, but we usually hold the onions up in the beakers by rubber banding them around a straw that sticks lower than the ends of the onions. That way the root bases aren't pushed against the bottom of the beaker.

I really only modified the materials that I provide the students to experiment with and how the results will be presented--since my students do a mini poster presentation of their results. The modified lab document can be found here.

The Gymnema Taste Lab and the Signal Transduction Pathway

When it comes to understanding cell communication and the signal transduction pathway, the Gymnema Tea Taste lab has become a class favorite. Of course, I first heard about this lab through my favorite source of ideas, the National AP Biology Teachers facebook group. You can find the write up for the lab at the Biology Corner here.

Last year, the lab happened to land on Grandparents' Day at our school. On that day, I not only had my students, but also many of their grandparents. I modified the lab to shorten it to the basics so I could hand the grandparents a one sheet lab that allowed them to also participate. This lab handout is here. The grandparents LOVED it! After the tasting, I handed students chalk markers to sketch out the signal transduction pathway on their tables with their grandparents.

I do think what tea you buy is important. The fist tea I bought did not work, but I've had great success with Buddha teas. I think part of the reason for success is having 100% gymnema sylvestra tea vs. just 48% gymnema.

This worked great for me, consistent results every time.

This did not work for me, even when I concentrated it.

One year, I had an exceptionally adventurous class. After they tried all of the foods I had provided in the lab, they went to their lunchboxes and tried bananas, strawberries and raspberries just to see what it would do with natural (unprocessed sugars). They were pleased to see that it really did work on fruits too. We also counted papillae after dying their tongues blue. As you can see in the picture, they were good sports about everything!