---- Sample Outline provided to students ------
Text to speech and speech to text are great features in Google docs, and students will be encouraged to take notes in this outline or in other formats that can be shared amongst their peers
Nucleotide base pairing outline
The way that DNA bases (the letters of the DNA alphabet) pair with one another is an important feature to the structure and function of DNA. Build upon this information provided here, and include links and resources you find useful during the course of this unit. I will keep backups of these periodically, and remember that your productive collaboration on these outlines is graded. With that in mind, let’s begin!
In this image, we see how Adenine (A) forms two (2) hydrogen bonds with Thymine (T). Below it, we see how Guanine (G) forms three (3) hydrogen bonds with Cytosine (C). Question: Why is it important that A-T bonds are different in configuration than C-G bonds?
Answer here:
- Answer discussed in class/ensured students reach, and that they include in here in their own words: By having a unique molecular “handshake,” DNA ensures that the message carried on the two strands is read in one and only one way. This is because A can only bond with T (or Uracil in RNA, more on that later), meaning that the transcript/copy will always preserve the correct location and identity of that A in the DNA strand.
As we explore the various models in class, think of other reasons why these hydrogen bonds are important.
List some of these below:
- Key points here: Hydrogen bonds are stable but can be “unzipped” to allow the DNA strands to be read, Hydrogen bonds do not permanently alter the component parts, provide some degree of strength to DNA molecule, etc
Links and Resources
Here is a Khan Academy video about the structure of DNA, one I find useful in exploring some of the basic features of DNA.
Notes:
This LearnGenetics model can help you visualize how growing DNA strands are built - notice how the number and configuration of hydrogen bonds are key to building a stable DNA molecule!
Notes:
Check out this JSmol view of an interactive DNA molecule. We will go over this one in class, as it can be tricky to use the software
Question: See if you can find where the phosphate backbone, ribose components, and nucleotide bases are in the molecule. Bonus points for identifying the bases correctly based on structure!
Notes:
Recall the handshake pairing exercise we did in class - practice with your partners and see how quickly you can match handshakes!
Question: See if you can come up with other models (hands, toys, drawings) that illustrate how complementary base pairing works
Notes:
- Model discussed in class - Left hand shakes represent AT pairs, Right hands represent GC. In either case, A and G are represented by a closed grip, and C and T represented by an outstretched thumbs. Right hands can only shake with right hands, left only with left. When modeled correctly, shows how nucleotide bases can only pair with complementary base
Assignment
Working with at least 2 partners, explore the links above. Explain the key features of nucleotide base pairing within the DNA, and end with a short reflection on which resources was most helpful and why. This can take the form of the following:
- a) a 500 word document in Google Docs, including at least 2 diagrams
- a 5 minute podcast with you and your peers
- a short video clip of you and your partners exploring a software/physical model of how DNA base pairs
- Another format - come to me with ideas!
If the above resources are confusing to you, discuss with me and we will explore new resources that might help you more.