What is DNA?

DNA is an abbreviation for deoxyribonucleic acid, and it’s present in all living organisms. If you isolate DNA from a cell and stretch it out, it looks like a twisted ladder. DNA is one of the main constituents of chromosomes in organisms, and it’s also the carrier of genetic information. Now you may be wondering, what does DNA do? DNA does multiple things from giving instructions to make proteins, to giving you your genetics which have been handed down from your predecessors (parents, grandparents, etc.). DNA has a variety of different bases – A, C, G and T. Depending on the sequence of these bases, that is how your genetic code is made. A always binds with T, and vice versa, and G always binds with C, and vice versa (A+T/T+A. C+G/G+C). Other than making our genetic code, these sequences determine the instructions for producing molecules inside our body. Everybody has 23 chromosomes from their father and 23 chromosomes from their mother. 46 in total. These can vary from eye colour, hair colour, height, baldness, heritable diseases/mental illnesses, etc. DNA also copies itself. How? Well, DNA replication has three stages – initiation, elongation and termination. During the initiation phase, enzymes called helicases unwind the double helix of DNA, by breaking hydrogen bonds. To prepare for the next step, the cell creates sequences of RNA called primers. With the primer as a starting point, a new DNA strand begins to rebuild, base by base. The existing strand is like a template for the new one! After elongation is complete, there is two new double helixes which will replace the original one. During termination, enzymes take off a telomere at the end of every replication. That leads to shorter strands after every new cycle. At the end, enzymes called nucleases go over the new DNA/double helix structures and remove any bases that were paired incorrectly. DNA polymerase then fills in any gaps that were left by removed bases, and boom! Replication.

For the edible DNA lab, my partner and I had to make a double helix (DNA) with correctly paired bases using marshmallows and twizzlers. The colors of marshmallows represented the bases such as A, T, G and C.