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Amino Acids on the MCAT

Amino acids are incredibly versatile in nature and, consequently, unsurprisingly comprise the foundation of multiple questions on the MCAT. Amino acids are prevalent in both the chemistry/physics section, or “Chemical and Physical Foundations of Biological Systems,” and the biology/biochemistry section, or “Biological and Biochemical Foundations of Living Systems.” (1) As a result, it is important to develop a great understanding of amino acids, including their specific properties and specific uses, for application to various passage topic types. Here is a quick introduction to what to know about amino acids and how to study them most efficiently to excel on these questions on the MCAT.

Amino acids are the building blocks, or monomers, of proteins. They are able to make up the primary structures of proteins. The binding of one amino acid to another is accomplished via a peptide bond performed via a dehydration reaction involving the loss of water. To break peptide bonds, a hydrolysis reaction is performed, involving the addition of water. There are several different types of amino acids, ranging from being hydrophilic or hydrophobic to polar and nonpolar.

Here is a specific table to assist you with memorization of amino acids!

It is crucial to be able to identify amino acid structures as well! Committing these structures to memory can be accomplished in various ways. This could be done by drawing out all structures until the structures begin to come to you more easily. However, learning these can be accomplished in different ways! Making your own set of flashcards on typical index cards or utilizing other resources with flashcard features such as Anki and Quizlet can be greatly beneficial in this regard! To find more information on amino acids, other resources such as Kaplan preparatory books or Blueprint live online courses may be helpful.

While the information provided in the table above and other information previously stated throughout this article is helpful, it is important to stress that rote memorization is not the key to conquering these questions on the MCAT. The MCAT emphasizes an ability to truly apply information to specific contexts. Consequently, with regard to amino acids, the MCAT may ask more passage-based questions, such as which amino acid would be best for forming disulfide bridges with a drug mentioned in the article or which amino acids would be most commonly found buried in lipid rafts within an identified cell membrane.

With this in mind, one of the best ways to practice applying your knowledge of amino acids is by completing practice questions and doing full-length practice exams. Specific practice questions may be accessed in various ways. One could find such practice questions by using resources such as UWorld and official AAMC material, including question banks and section banks.

The following are some discrete questions to test your knowledge of amino acids! If these questions are challenging to you, do not panic! Practice is the key to success, and you can only grow in knowledge.

1) Which of the following amino acids contains sulfur?

A. Methionine

B. Asparagine

C. Serine

D. Proline

2) Which of the following amino acids is not aromatic?

A. Tyrosine

B. Isoleucine

C. Tryptophan

D. Phenylalanine

3) Which of the following amino acids is the largest?

A. Histidine

B. Arginine

C. Tyrosine

D. Tryptophan

4) Which of the following amino acids is most likely to be found on the side of the cell membrane facing the outside of the human somatic cell?

A. Lysine

B. Aspartate

C. Valine

D. Methionine

5) Which of the following amino acids is the smallest?

A. Leucine

B. Glycine

C. Valine

D. Alanine

ANSWERS: 1A, 2B, 3D, 4B, 5B

For more clarifications on amino acids, watch this video!

I hope this was helpful! Happy studying- you can do this!

-Aprile Bertomo

Works Cited:

  1. “MCAT Sections: What's on the MCAT?” MCAT Sections: What's on the MCAT? | The Princeton Review,

  2. All amino acid pictures were taken from Wikipedia!

  3. Amino acid special properties:


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