It can’t be stressed enough how important MCAT Amino Acids are. Biochemistry has become a huge focus on the post-2015 MCAT and places a heavier emphasis on Amino Acids.
It is pretty much guaranteed that you will run into several questions on the MCAT that require you recall specific Amino Acids. And these aren’t questions you can infer from information in the passage, they require you simply know the characteristics of those Amino Acids.
Do yourself a favor and don’t miss freebies simply because you didn’t spend the time memorizing what you need to know about the MCAT Amino Acids. There are only 20 of them so it shouldn’t take too long!
What You Need To Know About Amino Acids For The MCAT
For all 20 Amino Acids the MCAT wants you to know the following information:
- Name
- Structure (Be able to draw it!)
- 3 letter abbreviation
- 1 letter abbreviation (Yup this is important too!)
- Polar, Non-Polar, or Neutral
- The basic and acidic Amino Acids
Really the most important thing you can do for the MCAT is to memorize how to draw each Amino Acid. When you know the structure by heart, you can fairly easily deduce if it’s polar/non-polar or one of the acidic/basic Amino Acids.
But don’t neglect the 3 and 1 letter abbreviations! The MCAT expects you to know these by heart.
Save Yourself on The Actual MCAT With This MCAT Amino Acid Tip
Here is an important MCAT tip that will help you make sure you don’t miss any Amino Acid questions on the MCAT.
When you are taking the actual MCAT, you will be given a 10 minute tutorial of the format of the exam. Obviously you have been taking MCAT practice tests that closely resemble the real deal so there is no reason to need this tutorial.
These 10 minutes are an opportunity to brain dump on the scratch paper you were given. The first thing you should do is draw and label all 10 Amino Acids.
Practice doing this before the actual MCAT. Time yourself to draw all 20 Amino Acids in less than 10 minutes. Make sure you are writing down the 3 and 1 letter codes, polar vs non-polar, and whether it is acidic vs basic.
Separating them by category is helpful so that retrieving that information later is no problem.
Now that you have all 20 Amino Acids on a piece of paper, simply keep that paper with you till the end and refer back to it as necessary. Trust me, having those Amino Acids right there helps tremendously. You don’t have to stop and think about the structure and category when you encounter an Amino Acid MCAT problem.
Time management is everything on the MCAT, this strategy will shave of minutes.
How are Amino Acid Synthesized
You will need to know how Amino Acids are synthesized. Specifically, the Strecker Synthesis and Gabriel Synthesis. Below is a quick 5-minute video from Khan Academy that will help you out if you are rusty on these reactions.
Further Reading: Is Khan Academy MCAT Prep a Waste of Time?
Peptide Bonds and Disulfide Bonds
Peptide and disulfide bonds for protein formation are also important to understand for the MCAT. You can look up videos in Khan Academy on the entire process but to keep it simple:
- Peptide bonds: The carboxyl group of one Amino Acid bonds with the amino group of another to form this bond. A water molecule is released during the process. These make up the primary structure of a protein.
- Disulfide bond: A covalent bond between the thiol groups of 2 cysteines. These bonds help form the tertiary and quaternary structures of proteins.
Calculating Charge and Isoelectric Point of An Amino Acid
The MCAT may ask you questions regarding calculating charge and isoelectric point for an Amino Acid or chain of Amino Acids. Leah4sci does a great job explaining how to solve these kinds of questions in this video below.
Of course, you can always look this up in your MCAT prep book or on Khan Academy.
What Makes Proline and Glycine Special
It’s important to know that Proline and Glycine are special Amino Acids.
Glycine is the only achiral Amino Acid due to the fact that instead of a side group it has an additional hydrogen atom attached to its alpha carbon.
Proline is special because its side chain connects to its own amino group. This gives proline a characteristic rigid structure.
What makes these 2 Amino Acids important is the way they affect secondary protein structures. Both Amino Acids, especially Proline, tend to disrupt the rigidity of the secondary structures. Proline, in particular, will create kinks (Or turns) in the protein structure.
Where Will You Find Polar vs Non-polar Amino Acids
For the MCAT it’s important that you know where you will find polar vs non-polar Amino Acids.
For instance, in a globular protein floating around cytoplasm, you will want the polar Amino Acids pointing outwards and the non-polar Amino Acids in the center.
MCAT Amino Acid Practice Questions
There are plenty of resources where you can find MCAT Amino Acid Practice Questions. I wrote an entire post with what I believe are the best resources for Biology and Biochemistry MCAT problems. It is here where you will find Amino Acid questions.
Although it is important to memorize these MCAT Amino Acids, it is also important that you practice questions involving Amino Acids.
Conclusion
Memorizing 20 different Amino Acids should not be difficult. If you make sure that you can draw and label all 20 on scratch paper in less than 10 minutes than you will be golden for the MCAT.
A lot of premed students find the synthesis and bonding characteristics of Amino Acids a little bit overwhelming. My suggestion to you is to not make it more complicated than it needs to be. The MCAT is not going to go into too much detail on these topics. Understand the key principles of these bonds/reactions and you will be fine.
Any questions? Have any other advice you can add? Please share in the comment section below!