3 Major Themes of Biochem

     The 3 major themes which seemed to connect all of Biochem are: structure, reactivity, and regulation.

Structure
     I've long heard in various science classes that "structure determines function." Yet, never before was this mantra more evident than throughout the various topics of Biochem. "Structure" was important in every topic covered, such as proteins (with 4 types of structure), nucleic acids, carbohydrates, lipids, and allosteric enzymes, to name just a few. The functionality of each of these types of molecules was dictated by their respective structures. Though I knew, for example, that the double-helix structure of DNA was crucial in its replication, Biochem introduced a new level of understanding. This is true for all the structures covered. Structure is the difference between a saturated and an unsaturated fat. Structure determines the action of allosteric enzymes. Structure was everywhere, and gaining a new level of understanding about structures facilitated comprehension of the function and reactivity of each respective molecule.

Reactivity
     The reactivity of molecules was a consistent theme, determined by the previously highlighted theme of "structure." The conformation of an allosteric enzyme, for instance, dictates whether it can catalyze a reaction or not. The reactivity of DNA Polymerase during replication is dependent on a free 3' hydroxyl group. The reactions of protein synthesis depend on the availability of each necessary component. So while it is easy to identify the key players in various reactions, understanding how, why, and when they actually are able to react with one another, was a key theme in Biochem. Some of these determining factors were known beforehand, but again Biochem illustrated these properties in new detail. I used to know DNA replication required an RNA primer, but now I know why. I used to know that enzymes can react under certain conditions and not others, and now I have a better understanding of why this is for many catalysts. The differences in reactivity of various molecules proved to be essential mechanisms of control for the numerous processes essential to life.

Regulation
     Combining the knowledge of various reactivities determined by structure, leads to the important theme of regulation. Sure certain molecules have certain properties which allow for specific reactions, but obviously the body does not want all of these reactions occurring at all times, uncontrolled. Regulation of biological functions is critical in terms of efficiency and necessity. DNA replication, transcription, translation, metabolism, etc. are all regulated processes, and they are regulated at multiple control points. I knew long before this class that most processes in the body were regulated, but this class taught me how, and why. I learned, for example, how one regulatory molecule may turn on a certain process, and how a different molecule may turn that same process off. I also learned how the same molecule can turn on some processes, while turning off others.

     The new found understanding of structure, reactivity, and regulation are all interconnected. These three themes were central to all the material we covered, and they served as yet another way to connect these complicated and diverse topics.