Ready to kick off your genetics unit? I prefer starting with DNA and then moving onto Punnett squares and inheritance patterns. For me, it makes more sense to teach DNA first and explain what a gene actually is. If you start with inheritance and use the word “gene” or “allele,” students won’t have the background knowledge needed to understand what the terms actually mean. Here is a list of resources to get you started!
DNA Structure
1. LESSON: What is the structure of DNA? I use a powerpoint lesson to introduce the topic with my students. You can find it on my website or on TpT.
2. MODELS: It’s fun to have students build some sort of model. Here is a template that I use to have students build models out of paper.
Students go nuts for candy, so if you are willing to spend a little money on supplies, you can have students build candy models instead.
3. VIDEO: How was the structure of DNA discovered? I LOVE this HHMI Biointeractive video that walks you through teams Watson and Crick vs Franklin and Wilkins. It is 17 minutes long, and definitely worth showing. If you want to make sure students are watching, have them write a summary at the end about the contributions of each scientist.
4. EXTRACTION LAB: Does every living organism have DNA? Yes! Get students excited by completing a DNA extraction lab. Here are some free step by step procedures to extract DNA from the following:
(Pictured is a the DNA from a cheek cell extraction. You can see the white stringy DNA collecting at the top of the test tube. Cheek cells don’t produce as large a sample as strawberries or wheat germ, but it’s free!)
DNA Replication
Students have mastered the structure, now how does it replicate?
1. LESSON: How does DNA make an identical copy of itself? What does the term “semi-conservative” mean? Check out this powerpoint lesson and foldable on my website or on TpT.
2. MODELS: My school purchased these DNA replication model kids from Wards. They are easy to put together and really help students see how the molecule splits down the middle.
Need a cheaper option? Grab some plastic pony beads from the dollar store and have students make these replication bracelets.
3. VIDEO: HHMI has done it again! Check out this short video clip that shows the process of replication in real time.
4. MUTATIONS GAME: Why is it so important for DNA to be replicated properly? What happens if mistakes are made? To simulate the process of genetic mutations, play the childhood game of telephone. Place ~10 students in a line, and hand a small slip of paper to the first student. On the paper should be a set of instructions like: The last student should clap their hands and then yell “A skunk sat on a stump and thunk the stump stunk.” The first student will whisper the phrase in the ear of the next student in line, and continue this process until the last student is reached. Have the last student follow the instructions they hear. How did they do? Talk about how when mistakes are made, it changes the instructions. When the same process happens in our bodies, instructions on what our cells should do get changed (circle back to this after protein synthesis). Here is a mutations worksheet from Flinn that you can do as well.
After exploring DNA structure and replication, I move on to chromosomes next. If you need ideas for teaching karyotypes, check out this blog post!
Rock on,
