I’m not going to lie; before this year I really didn’t know all that much about DNA. People would always talk about the A’s and T’s and the double helix and I’d nod along pretending that I knew everything they were talking about when I had absolutely no idea. I mean, it all sounded overrated. It seemed like a science topic that everybody was an expert on so I felt like there was no point in really exploring it further.
What I found out was this: Most people who talk about DNA really have no idea what the heck they’re saying and were running off the same principle of pretending to know about it because everyone else seemed to as I was. DNA is actually a really interesting group of molecules that is just as every bit chemistry as it is biology.
So what is DNA? It’s a thing called a polynucleotide. That just means it’s a string of nucleotides, or a string of nitrogenous bases, phosphate groups, and a sugar called deoxyribose (hence DNA or deoxyribonucleic acid). You may have heard of RNA as well which is basically the same molecular make up as DNA but contains ribose instead of deoxyribose.
What’s the function of DNA? DNA contains bases. These bases, A, T, G, and C for short, occur in sequence that code for certain genes – and eventually codes for proteins and enzymes that allow you to live. These two guys named Watson and Crick, two people credited with unlocking the many mysteries of DNA, found that different bases will only bind to one another. A binds with T and G binds with C.
One other thing that Watson and Crick discovered is that DNA is a double helix, meaning it consists of two strips of DNA that are intertwined in what essentially looks like a spiral staircase. This lady named Rosalind Franklin was actually the one who originally suggested this kind of orientation of DNA that Watson and Crick are credited with, however she passed away before the Nobel Prize was awarded.
Interesting Fact: Watson and Crick never produced any original data themselves. They simply analyzed the data others had collected (using the term “simply” very loosely here”).
So what holds the double helix together? The base pairs (A, T, C, and G) are held to each other by hydrogen bonds. That’s right, the same property that makes water “stick” at the surface is also responsible for holding DNA together.
Why is DNA in a double helix and not a single strand? As you’ll find out if you ever go to school for engineering or any of the physical sciences, everything is thermodynamically driven. In other words, the double helix is the most energetically favorable make up that DNA can attain under normal conditions.
I’ll write a more in-depth DNA article soon. Sometimes it’s just nice to get an insight into a very broad topic, especially a topic that you always hear about but aren’t always sure what the basics are!