Biochemistry Basics for Pre-Medical Students

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Biochemistry Basics

Table of Contents

What is Biochemistry?

Just like its name implies. Biochemistry is the science that looks at chemical processes in living organisms. Specifically, it tends to study processes related to energy and nitrogen production. 

Biochemistry can be a challenging course. You’re going to want to have some understanding of biology, organic chemistry, and chemistry before taking it. We’re not going to get into lipids, the urea cycle, or anything with plants here in Biochemistry basics, but prepared for that during your full course.

Biochemistry Reqs as a Pre-med

The Good News

  • As of now, the requirements for Biochemistry is just a single semester.
  • That one semester usually covers everything you need for MCAT + Medical school.
  • Even though chemistry, biology, and organic chemistry are required for the class, you typically won’t go into nearly as much detail into those subjects as you did during the core classes. 
  • Concepts you learned earlier – like enzyme kinematics, amino acid structure, protein formation, etc you’ll really learn in detail during Biochemistry.

The Bad News

  • Biochemistry is a challenging class, heavily focused on memorizing reaction sequences. 
  • The VAST majority of the biochemistry you’ll be learning will be focused on plants and fungi. So it won’t be very helpful in medical school.  
  • The MCAT LOVES Biochemistry. So you can’t just get through the class. You need to do well and understand what you’re studying. 
Now, let’s look at a just a few important concepts in Biochemistry!

Amino Acids, Proteins, and Mechanisms!

Notice your 20 key Amino Acids are the same ones you studied in Biology. 

You may have noticed certain similarities in their structures. For example, Alanine and Phenylalanine. You also may have noticed that we call certain Amino Acids essential. These two things are no coincidence! Your body has some incredible processes that turn one Amino Acid into another as needed. Your biochemistry class will review these mechanisms. Make sure you have a solid understanding of the key organic chemistry mechanisms!!

What we didn’t review, but will be in your exam is enzyme kinematics. These were probably first introduced to you during biology, but they become really important in Biochemistry as the focus shifts more to mechanisms and processes. 

Alanine can transform into Phenylalanine. 

Attaching phenyl rings like this is an organic chemists favorite thing in the universe. 

Protein and Protein Structures

In biology you’ll learn about proteins, carbohydrates, lipids, sugars, etc. Proteins become an especially important focus of your studies during Biochemistry. You’ll review all about how proteins fold based on primary, secondary, tertiary, and quaternary structures. Let’s review what that all means really fast.

  1. A protein’s primary structure is determined by the order of the amino acids that make up the protein.
    1. Remember they are connected from N-terminus to C-terminus.
  2. A protein’s secondary structure is determined by attractive and repulsive forces that cause the amino acid sequence to fold into sheets (alpha helixes, beta-sheets, turns)
  3. The tertiary structure is what forms when all of those sheets and helixes form on each other.
  4. The quaternary structure comes about when the forms of different tertiary structures interact with each other.
    1. This is VERY important. Hemoglobin is a classically studied example of or quaternary structure effects form and function of a protein.  

Glycolysis, Krebs, and the Electron Transport Chain

Another major focus of study in Biochemistry, one that directly builds off of the study of proteins is the study of metabolism. You’re going to learn this in biology, but there you’ll be spending your time focused on learning the steps and names. 

In Biochemistry be prepared to step it up a notch. You’ll be using your organic chemistry knowledge to literally follow the mechanisms and reaction of each molecule. Since so much depends on things you probably haven’t learned yet, let’s just review some classic metabolic processes instead. 

When you are studying these reactions and mechanisms you’ll want to pay special attention to which ones are reversible, which ones require energy, what substrates are needed, the key enzymes used, the net gain of energy, and where the reactions take place. All of these are key pieces of information you need to know to do well in the class.  

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