DNA Structure is a sugar phosphate backbone that has nucleotides on it. These nucleotides have complimentary base pairings Adenine – Thymine, Thymine – Adenine, Guanine – Cytosine, Cytosine – Guanine. How ever these base pairs are on an anti-parallel strand that connects with hydrogen bonds. As you can see in the first photo it has the first backbone with the first set of Nucleotides on it. Then in the second photo when connected to the other backbone the nucleotides are complimentary base pairs. If read then this 2nd backbone would be read upside down because it is anti parallel.
This activity helps model the structure of DNA because the different colors of everything allow you to understand the different parts of DNA. Having the pink beads be phosphate with the blue being sugar helped me understand the Sugar-Phosphate backbone a lot more. I think to make this more useful bigger supplies could be used so that they could potentially be labeled to really make everything stick.
DNA replication occurs prior to cell division. The first step is the unzipping and unwinding of the DNA with the DNA Helicase. The second step is the base pairing where the DNA Polymerase will read the single strand and build a second one with complimentary base pairings, in this step the 5′ – 3′ strand is the leading as the polymerase works in the same direction is the helicase. Whereas the 3′-5′ strand is lagging as the polymerase works in the opposite direction of the helicase so it has to go back and get the next strand. The 3rd step is the Ligase gluing all of the lagging strands together to create a full DNA strand. These pictures show case this. With the first one being the helicase unwinding, the 2nd being the polymerase rebuilding the new DNA back bone and the 3rd being the ligase glueing the lagging strands
This activity was well suited to show the understanding of DNA replication. It helped me understand how the different enzymes work to unwind and rebuild. It wasn’t great to show the lagging and leading strands because of the way the pipecleaners were long and we were unable to cut them so we had to fold them. Overall this was a good way to learn about DNA replication
