This 30 minute lesson is my favorite way to start our unit on DNA. The film clip and the conversations we have around it introduce DNA as an intriguing phenomenon in science. It seems mysterious and almost magical to students, which inspires their curiosity and desire to learn more. That makes it fun and easy to teach!
The purpose of this lesson is to begin to engage students’ minds on the topic of DNA.
I hope these ideas help and save you some valuable time and stress! In this blog post I share ideas for an introduction lesson to DNA:
- Background knowledge
- DNA: What do we know? (~5 min)
- Think-Write-Pair-Share (~10 min)
- Twin Study Film Clip (~11 min)
- Film Questions and Discussion (~10 min or more!)
- How this Lesson Makes DNA Relatable to Students
- What’s Next in Learning About DNA?
Background Knowledge
Before learning about the molecule DNA, we studied Macromolecules. We learned that macromolecules are polymers made up of smaller units called monomers. Carbohydrates, Lipids, Proteins, and Nucleic Acids are macromolecules that are the building blocks of life.
All living things are made from these molecules: plants, humans, animals. We get most of them from food, except for nucleic acids (DNA & RNA) which we get from our parents. We don’t need to replenish our DNA the way we need to eat carbs, proteins, and fats to replenish them in our bodies to use for different reasons (like they all give us calories for energy, for example).
You can even use the above as a Teacher Script introduction speech to students. It reminds them of what they learned about macromolecules and how it connects to the new unit: DNA.
DNA: What Do We Know?
A great way to introduce DNA is to discuss how DNA influences the way we look and behave.
Activating prior knowledge is a best practice in teaching. Great teachers access what students already know and bring it to the front of their minds so they can make connections and build on that knowledge.
Before the video, students think about what they already know about DNA, and we discuss each question as a class by doing a Think-Write-Pair-Share:
- How do genes (DNA) affect the way you look and act?
- What traits did you get from each of your parents? (the sperm and egg that made you)
- Do you think who you are is more dependent on your DNA or your environment (where you grew up)?
With DNA, many students know that we share traits with family members. We get our genes from our parents, and we may have inherited certain traits like height, hair color, eye color, skin tone, and even a sense of humor from one parent or another. We learn about inheritance, traits, and genes later on in Genetics, but I like to start DNA like this because it piques their interest and they know more about it than they are probably aware of.
Think-Write-Pair-Share
I give students silent time to think about the questions and write down their answers individually. I go around the room and read their papers to get an idea of what they are thinking.
After a few minutes of thinking and writing time, students Pair-Share their answers. I let them know that I will call on students to share their answers with the class, so if they couldn’t think of anything before, now is the time to get some ideas from their partner to write down and possibly share out.
Starting with Question 1, Partner A reads their answer to Partner B. When A finishes, Partner B reads their answer to Partner A.
When it sounds like everyone has shared, I signal to the class for their attention and I call on 3 students to read/share their thoughts. I write their ideas under the document camera for everyone to see, and students add new information and details to their notes.
We move on to Questions 2 and 3 in the same way, alternating which Partner shares first.
Think-Write-Pair-Share is another teaching strategy. It fosters participation. It is also a form of collaborative learning, and is even useful for differentiation. There are different ways of doing Think-Write-Pair-Share, like having students share out what their partner said, or agreeing or disagreeing with their partner’s thinking. This is just an example of one way to use it here.
DNA Twin Study Film Clip
I love to show this short TED Talk about twin studies; Twins: A Window Into Human Nature. In the video, the presenter Nancy Segal discusses cases of twins separated at birth, and raised without knowledge of one another.
What we learn in the video is that despite differences in their environments, there are some striking similarities in the twins’ appearances, preferences, and behaviors. For instance how they wear their jewelry, hold their drinks, and even coincidences in the names of their spouses!
Students usually find it really interesting, and ask awesome questions. Especially about the process of making identical twins vs. fraternal twins. It’s even more exciting when we have an identical or fraternal twin in the class!
Film Questions and Discussion
After the video students usually have a lot of thoughts and questions. Some classes get really into this topic and we have longer discussions, so I recommend you have some flexibility with the rest of your time and lesson plan for the day!
We go over each question together. I call on volunteers, or explain and write notes under the document camera for students to copy.
Questions to discuss and answer together after the video:
- What are twins?
- What are fraternal twins? What are identical twins?
- What did the twin study tell us about genetics?
Twins are babies that are born from the same pregnancy. Fraternal twins do not have identical DNA. They are made from a separate egg and sperm cell. The mom just happens to release 2 eggs that cycle instead of 1, and each one is fertilized by a different sperm. Fraternal twins are as genetically similar as regular siblings.
Identical twins have identical DNA made from the same egg and sperm. The fertilized cell divides in two, and they develop into 2 identical babies.
The twin study shows us that genetics and DNA seem to determine more than just physical traits. Such as likes, dislikes, personality traits. Even phobias, addictions, and illnesses.
How This Lesson Makes DNA Relatable to Students
DNA and Genetics are some of my favorite topics to teach in science. Every year my students are really interested and have so many questions. They spark great discussions, like in this lesson, that make class fun and memorable.
DNA is fun to teach because it is so relatable for students. We all have unique DNA and combinations of genes that make us special as individuals. And yet, the molecule DNA is made of nucleotides that are simple to explain and learn about. Despite our differences in looks, likes, dislikes, and behaviors, we are very similar at the molecular level of DNA. As humans we are united in that way.
DNA could be overwhelming and intimidating to students if approached in a different way. For instance if we dove straight into what a nucleotide is, or genes, or the genetic code! That’s what makes this such a great lesson and starting point for teaching DNA. It feels like the dots really connect for students, which I can’t say for every topic I teach!
What’s Next in Learning About DNA?
After this introduction, we start our DNA Notes in the same block period. The notes are a general overview about the components of DNA, the structure, nucleotides, complementary bases, and the sequence of base pairs which is the “genetic code.”
After DNA Notes, we go deeper into the structure of DNA by doing lots of modeling. We draw and label a diagram of 8 nucleotides, create a paper class model of DNA, make DNA keychain models, and more! DNA is fun to teach and learn about because there are lots of hands-on lessons and activities that students enjoy doing. Check out my blog posts How She Teaches DNA Model Keychains and DNA Model Keychains: An Engaging Hands-on Lesson and Fun Activity Before Holiday Break! to read more about one of my all-time favorite lessons to teach .
Let me know if you have any questions by leaving a comment. I would love to hear from you! To read more about me and my classroom, check out the blog posts below!
https://howsheteaches.com/2022/11/26/how-she-teaches-what-is-a-system
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