DNA: The Double Helix (Structure & Function Coloring Activity)

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Objective

Students will become more familiar with the way that DNA and RNA nucleotides are built (sugar, phosphate, and nitrogenous base) and how they relate to each other.

Big Idea

DNA and RNA are complex macromolecules whose structure begets their function.

Learner Goals

Note: I recommend that you first check out this resource in order to get the most out of this lesson!

In high school I took several drafting classes and, for a while, I had hoped to become an architect. With respect to planning instruction and teaching, I feel that I can still live out the detailed approach to building something intricate and complex even though the product is a lesson rather than a certain "built environment".

The lesson-planning document that I uploaded to this section is a comprehensive overview of how I approach lesson planning. This template includes the "Big Three" aspects of the NGSS standards: Disciplinary Core Ideas, Crosscutting Concepts, and Science Practices. Of course, there are many other worthy learning goals, skills, instructional strategies, and assessments that can be integrated into a class session. I don't feel compelled to check every box but, rather, use it as a guide to consider various options and tailor the lesson in light of these.

With regard to this particular lesson students will be able to say...

1. I can explain that all cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells. (Emphasis) HS-LS-1 & LS3-1
2. I can recognize the abbreviations of both forms of nucleic acid.
3. I can describe how DNA & RNA nucleotides (including mRNA, tRNA, and rRNA) are built.
4. I can compare and contrast DNA and RNA (show similarities and differences).
5. I can explain the relationship between monomers and polymers of the DNA and RNA polymers.

I hope you get some value from my work!

Anticipatory Set ("Hook")

5 minutes

Teaching Challenge: How can I develop my students' ability to apply unifying ideas to make connections across science content?

The idea (cross-cutting concept) of structure & function unifies all of the sciences, from the built environments created by engineers to the natural world of atoms, cells, and the universe beyond. According to the authors of A Framework for K-12 Science Education, "Form and function are complementary aspects of objects, organisms, and systems in the natural and designed world... Understanding of form and function applies to different levels of organization." (p. 96)

The authors state further that, "As students develop their understanding of the relationships between structure and function, they should begin to apply this knowledge when investigating phenomena that are unfamiliar to them. They recognize that often the first step in deciphering how a system works is to examine in detail what it is made of and the shapes of its parts." (p. 98)

Teaching Challenge: How do I support my students develop and use scientific models?

 So in this vein, I want students to recognize the form of closely related genetic molecules (with an eye for similarities and differences) as well as visualizing them as a model, albeit not a 3-D physical model. Truth be told, models come in various forms!

Once students have grappled with the complex nature of the DNA (and RNA) molecule, the emergent properties embodied in the Central Dogma are more easily understood.

Self-assessment I:

As for the progression of the Anticipatory Set, I direct students to refer to their Unit 4 Map and as we read through the lesson's goals, to self-assess their initial understanding of them according to the A-B-C strategy outlined here.

 

Instructional Input/Student Activities

45 minutes

DNA: The Double Helix student packet

Text Passage:

Depending on your emphasis and time, this activity could be expanded into a more formal strategy for enhancing reading skills. Science Practice #8 addresses "Obtaining, evaluating, and communicating information". In essence, students should be able to read a scientific text, including diagrams and explain the key ideas being communicated. In this lesson, I wanted to focus more on the visual structures of both DNA and RNA with a more minor emphasis on the reading task.

In light of this, students are prompted to read the first two pages and use this information to answer questions on page 3. Reading is still a focus but only in a more informal sense.

Color-coding nucleic acids (DNA & RNA):

The aforementioned reading passage also indicates the color-coding scheme to be used to color the structures of DNA and its close “cousin” RNA on the remaining pages. I require a higher standard of quality and completeness for this assignment since this portion of the task is more time-consuming and involved. My criteria for meeting standard include use of proper colors, attention to neatness, and completion of all structures/diagrams.

Students quickly notice how complicated the structures are as well as the similarities shared among and between the nucleic acids. Yes, the coloring can be tedious but the time flies past as students are interacting with each other. "Art" days are a lot of fun since it is more social and it can seem like a "break" from the typical science task.

I, for one, love art and try to incorporate it as much as possible! My class theme of "Investigate-Communicate-Create" is fully ALIVE! Muwahahahahaaa! (attempt at pseudo-nefarious mad scientist)

Here are a few samples of what the finished product might look like: Nucleic Acid Drawing and Nucleotide Drawing

 

Closure: What did we learn? Where do we go from here?

5 minutes

Self-assessment II: Either at the close of class today (time available) or at the start of the next class, I will revisit the learning goals for this activity to determine whether (and to what extent) student understanding has improved.

Every story has a beginning, a middle, and an end. Have students been given the time and tools to understand today's story?

I try to be consistent each day to properly "land the plane" and allow for an intentional closure to class (in the midst of students' eagerness to pack up and head out). I resist this natural urge and, on occasion, have kept classes after the bell if they haven't given me their focus and attention to do this. Think about it this way, how well would we be nourished if the food just consumed wasn't properly digested and dispersed to all of our cells?

In a way, isn't this similar for the brain and the interaction between short-term and long-term memory?

Lesson Extension & Follow-Up Activities

If students did not finish the activity in class, then they have homework! Oh yeah!!!!