What knowledge have you connected with past knowledge?

Ah, yes- your eyes are correct; your synapses are firing in the right directions; you are not mistaken:  You have read this question before- precisely two entries back!  Since this is a repeat question, I have chosen to approach my answer a bit differently this time:  I will begin my answer with a bit of an editorial angle before I label several specific connections that biochemistry has made for me with past studies.  However, before I do so, it is noteworthy to point out that this same question could be used for each week’s blog entry for this class, for biochemistry is full of connections to knowledge I have previously gained in past classes and explanations of "why and how".

On the Editorial Side: 

I simply love the Biochemical Connections boxes in our text:   As a student of medical and health sciences, these lovely little half-page snippets have become a lifeline for me, as they often connect complicated sequences of biochemical steps to the world I am working to enter into, through explanations of how these processes, or problems with the processes, cause various diseases or genetic differences.  Others explain the basic physiology of which I have previously studied in further detail and provide a thoughtful pause to make these connections of how chemistry basics are the fundamental basis behind what we are studying.  Taken together, each of these Biochemical Connections boxes is analogous to an island oasis in the midst of an ocean of protein abbreviations, nucleotide sequences and nucleophilic attacks!

Recent Connections:

In the most recent chapters of study, we have been immersed in the world of DNA.  Namely, the study of the biochemical processes of DNA replication, transcription and translation.  Thus, I felt it most appropriate to focus on a discussion of specific examples of connections I have made to past knowledge in these areas.

Connecting back to Microbiology:

In our recent study of DNA replication, we learned about the processes of proofreading and repair mechanisms in prokaryotic DNA.  In addition to errors made in replication to cause mutation, other mutagens can also have an effect on damaging DNA sequence and structure.  In this section I immediately connected back to my study of Microbiology when we learned about these various sources of mutagens, specifically UV light’s ability to cause thymine dimers; the formation of π electron bonds from the 5^th C and 6^th C of two adjacent thymine bases, which can alter the shape of the DNA molecule and cause errors in transcription and replication.  I understood this in my previous study, but only on a very high level.  Now, with my understanding of Organic Chemistry and Biochemistry, I can understand the nature of the bond that is formed and why this alteration in the three dimensional structure of the DNA molecule has such a drastic effect on the replication and transcription processes.  This connection also extends to the processes of repair mechanism and the need for recognition of the “correct strand”.  I distinctly remember learning in Microbiology about how prokaryotic DNA use methylation to flag the parent strand.  My understanding of this process stopped here at the time.  Now my understanding is much more complete, as I can connect back to Organic Chemistry and to Biochemistry and know that the adenine bases of the parent strands are methylated (meaning that -CH₃ is added) before replication, allowing enzymes to distinguish the parent strand (one without the mistake) from the newly synthesized stand (one with the mistake) and make the correction accordingly.

Connecting back to Anatomy & Physiology:

Another example I will give demonstrates connections between recently learned biochemistry concepts with those learned in Anatomy and Physiology.  This example involves the transcription factor cyclic-AMP-response-element-binding protein (CREB) which, in a neuron, activates genes associated with synapse-strengthening proteins that influence the development of long-term memories.  Reading about CREB and its role in the neuron provided a long overdue explanation for what those calcium ions were doing during depolarization when the calcium channels are opened:  They were activating enzyme pathways that ultimately activated CREB which activated the appropriate genes for the appropriate synapse-strengthening protiens!  I found this connection very interesting, as it provided a very specific example of the effect that transcription factors have on transcription and gene expression and connected with the broader level understanding of neurological function that I studied in Anatomy and Physiology.  In this sense (and, of course, many more examples that are like it) biochemistry has provided me with the explanation of "why and how" and the details that were missing in some of my prior studies.  This missing “why and how” have often times plagued me, as I have always thought it would be easier to understand the structure and function of the nervous system (and other biological systems) if I just had more detail to understand the underlying processes.