Biochemistry Revisited

I thought I would spend a bit of an essay discussing the nuts and bolts of Biochemistry. This class is usually taken along with Gross Anatomy and thus it can be a problem for some students.

My prevaling theme in all medical school classes is to keep up with the material. I cannot emphasize this more because good medical students find themselves failing because something (illness, family illness, emergency) interferes with their studies and they fall far enough behind and are unable to catch up or keep up. Biochemistry can be one of the most “unforgiving” courses if you fall behind. This class ranks right up there with Gross Anatomy in terms of volume of subject matter. It is vitally important that you do everything that you can, not to fall behind. If you do fall behind, you must catch up the very next weekend. Again, weekends are catch up days so don’t use weekdays to catch up. Go immediately to where the class is and keep moving until Saturday.

Biochemisty is the “chemistry ” of large molecules. These molecules are proteins, lipids, carbohydrates and nucleic acids. Since you are dealing with chemistry, you have to remember the subject matter of chemistry. This includes polar versus nonpolar, molecular shape, molecular funtion and chemical reactions. Most of the biomolecules are composed of carbon, hydrogen, oxygen and nitrogen and thus you need to be fairly familiar with the chemistry and characteristics of these elements. You also need to be familiar with the effects of water, pH and electronegativity. Throw in some enzyme kinetics and some equilibrium chemistry and you have the basis of biochemistry. The rest is application of the above characteristics and principles.

Biochemistry is NOT organic chemistry though we are a “carbon-based” life form. You need to understand carbon in terms of its covalent bonding and simularity in electronegativity when it is hooked to hydrogen but get rid of sp3, sp2 and sp1 bonding, free radicals and all of those synthetic schemes that you memorized in organic chemistry. In biochemistry, you are studying how reactions take place not why these reactions take place. They are already there but you have to put them together. Most of the reaction pathways in biochemistry involve hydrolysis, dehydration, hydration, oxidataion and reduction. You also need to know enzyme catalysis and you will be largely set.

Carbohydrates are polyhydroxy (poly alcohol) aldehydes and ketones. Amino acids have the amino and carboxyl characteristics (weak acid and base) and nucleic acids are based on their sequences, formation and degration. Lipids are non-polar and thus have the simpliest chemistry and function. That’s the essence of the biomolecules.

Now all of these biomolecules have pathways, locations and functions. You can sit down and rote memorize the pathways but it is far more effective to ask yourself, “What are the substrates of these pathways?” “Where is the pathway located?” “Why does the body need this pathway?” and finally “What are the products of this pathway?” From that lauching pad, you can look at the individual reactions and enzyme characteristices (oxidation, reduction, hydrolysis, hydration, dehydration) and figure out where the regulation points are found. “Is the body building up a macromolecule?” or “Is the body tearing down a macromolecule for storage, ATP production or production of reducing equivalents?”.

Other subjects of biochemistry are signal transduction pathways, hormones and functional characteristics of important molecules like hemoglobin, collagen and elastin. You will also study post translational modifications of proteins and how these relate to their function. Always remember to link structure with function when you are studying macromolecules. Think about glycogen and its function as a storage form of glucose. Glycogen is made up of multiple molecules of glucose and thus the pathway for its formation and degradation is going to involve glucose molecules. You need to know where other sugars feed into this pathway (where they feed into glucose metabolism), etc. You need to know where glycogen is stored (muscle and liver) and what the regulatory points of glycogen synthesis and degradation are. After that, you can look at the individual reactions of glycogen synthesis and glycogen storage in relation to the regulatory points of each pathway.

Bottom line for biochemistry is that you need to see the “big” picture and fill in the details. Never lose complete sight of the ultimate reason why you are studying the details. This is why my method of scanning the syllabus at the beginning of the semester (gives you an overview of how the course is organized), pre-viewing the next days lecture and reviewing the previous day’s lecture before you study and learn the present lecture is very important. Again, you have to organize the material so that you can learn it efficiently.

Finally, a good review book like Harvy & Champe’s Biochemistry is good to have but it cannot be the major source of your study. The best use of this book (also known commonly as Lippincott’s Biochemistry) can help you summarize things or put things together but cannot substitute for your class notes or text book. Review books do reviews and you cannot “review” what you have not “learned ” in the first place. Don’t make a major mistake of believing that you can memorize a review book and that is what you will need to do well in your coursework. Review books can be good adjuncts to study but cannot replace your text, syllabus and notes. You can use your review book as a means of pre-viewing your lecture but your syllabus and the objectives that it contains are you guides in mastery of the material.

There are loads of new terms that will be introduced to you in your medical biochemistry course. You do not need to have taken undergraduate or graduate biochemistry before medical school. If you have throughly mastered your undergraduate pre-med chemistry coursework (that is general chemistry and organic chemistry), you have more than enough tools to master medical biochemistry. Do not fall into the trap of taking an undergraduate biochemistry or graduate biochemistry course unless you have plenty of time to master these courses or a passionate interest in the subject matter. If your medical school requires undergraduate/graduate biochemistry, then you have to take the course to meet a pre-req but most medical students are able to do well and pass this course without a previous biochemistry course. Also, most organic chemistry texts contain a very nice introduction to biochemistry that will get you on your way.

Do not fear Biochemistry because like the rest of medical school, its mastery depends more on organization and diligent mastery. In that first week (as soon as you get the syllabus in hand), start making out your study schedule. Never go to class unprepared (you can at least skim the syllabus) meaning that you know what the important points of the lecture will be and you know what is in the book so you are not trying to listen to the lecture cold. Don’t forget to review the previous lecture (you have already studied and learned it at this point) before you tackle study and learning of the present lecture. A review book is an adjunct to your lecture material and not a substitute. Use a review book to review and supplement your class lectures if you like.

First Year of Medical School

A short while back, some of my pre-med students asked me about memories of medical school. I thought it might be fun to write about some of those here as well as residency experience so here goes from the beginning…

My medical school had a classical curriculum with problem-based-learning intergrated. We had the typical first-year, second-year types of classes. Lectures went from 0800h to 1600h daily. We had some Tuesdays or Thursdays when we would be able to get out earlier but we spent loads of time in class (way more than students currently attending). Some of my classes had computer-based-learning exercises and some had laboratory projects that had to be completed. In short, school was the equivalent of a full-time job with much time spent on weekends reviewing and keeping up with the pace. The best thing was that all of my classes were very interesting.

My first lecture of medical school was in Biochemistry. The professor essentially covered an entire Organic Chemistry course in a 50-minute lecture. The material was extremely detailed and presented in volumes. This particular professor had a reputation for “rocket” lecture delivery and he got the job done. The great thing was that I understood everything well and could see that this was the basis of the next 50-minute lecture which started off with lipid biochemistry.

My next class was the first part of Gross Anatomy. Our lecture was on surface anatomy and types of neurons. Each lecture was 50 minutes followed by a 10-minute break. I think those 50-minute lectures were the beginning of my 50-minute attention span. After lunch, Gross Anatomy lab started with a brief introduction and then a long laboratory on the vertebral column. We were all given bone boxes (containing human bones) to take home for further study. Every bone was present except the skull bones. Needless to say, we were required to learn every bone and every part of every bone.

By the time the day was done, I had received the equivalent of about 3 weeks worth of undergraduate lectures on one day. Since I had my syllabi, I knew what would be covered in lecture and I knew what readings and material would have to be previewed for the next days lecture. After each lecture was completed, I would quickly fill in any gaps in my notes and briefly scan through my notes for completeness. Over lunch, I would start to memorize as much of my morning lecture as possible too. We had an hour for lunch so I would grab something quick and then spend the rest of the time pouring over my notes.

On the way home, I would study some more or just watch people. I took public transportation because I didn’t want to worry about driving. My commute time was my time to relax and think about the day or plan my evening. When I got home, I would grab my gym bag so that I could get a quick swim in before dinner. I would dine with my fiance and then hit the books for a couple of hours. By that time, it would be around 8pm so I would go to bed. I would wake up at 2am and study until 6 am. I would then take a shower and get off to school.

When I was studying, I would finish studying the material that had been presented that day. I would then review the lectures for the day before and preview the materials for the next day’s lecture. On the weekend, I would review the entire week’s lectures in addition to reviewing an entire week’s dissection in the Gross Anatomy lab.

I made study tapes to drill structures and notes so that I could listen to them while I was walking or running. I would also make concept maps and fill them in on large sheets of paper as I went through biochemistry. I always wanted to keep the “big” picture in mind as I studied.

We had an exam week about every five weeks during the semester. There would be two “reading” days (read catch up) and then exams would begin. For Gross Anatomy, we would have the lecture exam in the morning and the laboratory practical exam in the afternoon. Between the exams, I would go to the art museum and get completely away from campus. I couldn’t stand to be around people who were so stressed about the exams.

In addition to Anatomy and Biochemistry, we had lectures in Psychiatry and Introduction to the Practice of Medicine. The Psychiatry lectures were always interesting and covered topics like development, personality disorders, sexuality, psychiatric drugs and the roles of various types of psychiatrists. Lectures in the practice of medicine covered topics like law and medicine, types of practices, alternative and complimentary medicine, history of medicine and medical education models. Psychiatry and Introduction to Medicine provided a bit of relief from the rigor of Biochemistry and Gross Anatomy but we were tested on these subjects so they required our attention too.

Our first semester ran from the middle of August to the second week of December. I can promise that the time goes by very quickly and soon Christmas vacation upon us. At the end of the first semester, we were done with Gross Anatomy and Biochemistry but still had more lectures in Psychiatry and Practice of Medicine. In addition, we had Histology, Microbiology/Immunology and Neuroscience lectures too. Second semester had a bit more material and more lectures. In addition, we had to dissect brains and spinal cords in Neuroanatomy. We were also given slide boxes with every type of tissue for histology. We would learn to recognize tissues and electron micrographs of every type of cell.

By the time second semester is over, we had learned a huge amount of material. Most people were happy to get exams done and get home for the summer. I was selected to become an instructor for the students who would be coming into our pre-matriculation program. I would be teaching Biochemistry primarily in addition to Gross Anatomy and Immunology. It was an honor to be asked to instruct in this program and I knew that I would enjoy working with these students.

The students who participated in the prematriculation program were medical and dental students with a conditional acceptance into medical or dental school. By successfully completing this program, these students are offered a seat in the school that they were conditionally admitted to. During this rigorous summer, we gave study tips, extensive reviews and got to know some very determined folks. In addition, these students have a huge head start when the actual courses start because they have been exposed to the material. It is a great program and I enjoyed the summer. In addition, we, the instructors are paid very nicely and can get some research done at the same time.

I finished my first year strong with honors and a much stronger interest in medicine than before I started school. When I looked back on all that I had learned, I was amazed. Little did I know that second year had even more to learn and would build upon my foundation of first year.