1. Explain the structure of DNA. 

DNA’s structure is made up of sugars, phosphates and nucleotides. The sugars and phosphates form the antiparallel strands that nucleotides hold onto. There are 4 different nucleotides in DNA; adenine, guanine, cytosine and thymine. Adenine and guanine make up the group of purines which have a complimentary base pairing  with the pyrimidine group, consisting of thymine and guanine.

2. How does this activity help model the structure of DNA? What changes could we make to improve the accuracy of this model?

This activity was helpful in modeling the structure of DNA because of the fact that it was a 3D model for us to work with. Seeing the different nucleotides as different coloured beads was helpful for us to have a visual representation of what each base is like. In the future, it would be better if we could somehow see the splitting of the DNA in a more accurate way.

3. When does DNA replication occur?

DNA replication occurs when a cell needs to divide in order to repair or replace another cell.

4. Name and describe the 3 steps involved in DNA replication. Why does the process occur differently on the “leading” and “lagging” strands? 

The first step in DNA replication is unwinding and unzipping. This is done by the DNA helicase which unwinds the helix shape and unzips the complimentary base pairs. The second step is the complimentary base pairing. DNA polymerase facilitate the bases pairing up and forming an H-bond with each other. The final step of replication is that ligase joins the ajoining bases together. Joining the bases completes the 3 steps to replicate DNA and creates 2 daughter strands out of the 1 parent strand. The leading strand keeps going as the DNA unzips. Lagging strands start in the opposite direction and it is connected to the other strand by DNA ligase.

3. The model today wasn’t a great fit for the process we were exploring. What did you do to model the complimentary base pairing and joining of adjacent nucleotides steps of DNA replication. In what ways was this activity well suited to showing this process? In what ways was it inaccurate?

We used pipe cleaners and beads to demonstrate DNA replication. It was effective in showing what happens to the leading strand of DNA, however, it didn’t work in showing what happens to the lagging strand. We had to cover the strand with paper in order to represent the division process.

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