The MCAT Chemistry and Physics section is often feared by test-takers. Throughout its 59 questions, students are asked to utilize knowledge from intro-level biology, organic and inorganic chemistry, physics, biochemistry, molecular biology, and much more. As intimidating as this sounds, going over high-quality MCAT Chemistry questions as part of your MCAT study schedule can significantly help build your confidence on this challenging section. Moreover, chemistry in many forms appears throughout the MCAT, so building your confidence is key to improving your total score as well. This blog is the ultimate guide to understanding what is assessed in the first section of the MCAT and how to successfully prepare for it. We also take a look at several MCAT chemistry and physics sample questions and provide expert breakdown of the answers.
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Sample MCAT Chemistry and Physics Questions
Start your prep with some MCAT chemistry practice passages. Below you will find several Chemical and Physical Foundations of Biological Systems sample questions to test your skills for this section of the MCAT:
Passage
The heme enzyme indoleamine 2,3 dioxygenase (IDO) catalyzes Reaction 1, the first and rate-determining step of L-tryptophan (Compound 1) metabolism and is an important enzyme of the human immune system.
The IDO-catalyzed oxidation of Compound 1 by H2O2 does not occur. However, researchers have recently discovered that IDO-catalyzed oxidation of indole (Compound 3) by H2O2 (Reaction 2) does occur.
Under the conditions employed, the number of catalytic turnovers appeared to stop at roughly 100, on average. A plot of the concentration of Compound 3 that was oxidized versus the concentration of H2O2 employed, at two different initial concentrations of IDO, gave the results shown in Figure 1.
Aerobic oxidation of Compound 3 in the presence of 18O-labeled H218O2 resulted in the formation of 18O-labeled oxidation products (Table 1).
The formation of Compound 6 does not appear to be the result of a sequential oxidation process. Isotopically labeled Compound 4 does not exchange 18O for 16O in water over 3 hours, but Compound 6 completely loses its 18O label in unlabeled water over the same time period.
Adapted from: Kuo HH, Mauk AG. Indole peroxygenase activity of indoleamine 2,3-dioxygenase. Proceedings of the National Academy of Sciences of the United States of America. 2012;109(35):13966–71.
Looking for more on what the chemistry and physics section looks like? Check this out:
Sample Questions:
1. The progress of Reaction 2 can be monitored by observing what change to the IR spectrum of the product mixture?
A) Appearance of a broad peak at 3400 cm–1
B) Disappearance of a broad peak at 3400 cm–1
C) Appearance of a sharp peak at 1700–1750 cm–1
D) Disappearance of a sharp peak at 1700–1750 cm–1
2. The following kinetic parameters were obtained for the IDO-catalyzed oxidation of Compound 3 by H2O2 in the presence of L-Trp.
Based on this data, what effect does L-Trp have on the reaction?
A) L-Trp oxidizes Compound 3 directly.
B) L-Trp is oxidized instead of Compound 3.
C) L-Trp does not interact with the enzyme.
D) L-Trp inhibits the enzyme.
3. Which experiment can be used to show that Compound 6 is not formed sequentially from either Compound 4 or Compound 5?
A) Conduct the reaction of Compound 4 with Compound 5, and identify the products.
B) Oxidize Compound 4 and Compound 5 with IDO/H2O2, and identify the products.
C) Reduce pure Compound 6 without added catalyst, and identify the products.
D) Conduct the reaction of Compound 2 with H2O2 without added catalyst, and identify the products.
4. In Michaelis-Menten enzyme kinetics, what is the velocity of the reaction when the substrate concentration is equal to KM?
A) ¼Vmax
B) ½Vmax
C) Vmax
D) 2Vmax
5. The radius of the aorta is about 1.0 cm and blood passes through it at a velocity of 30 cm/s. A typical capillary has a radius of about 4 × 10–4 cm with blood passing through at a velocity of 5 × 10–2 cm/s. Using this data, what is the approximate number of capillaries in a human body?
A) 1 × 104
B) 2 × 107
C) 4 × 109
D) 7 × 1012
6. A test for proteins in urine involves precipitation but is often complicated by precipitation of calcium phosphate. Which procedure prevents precipitation of the salt?
A) Addition of buffer to maintain high pH
B) Addition of buffer to maintain neutral pH
C) Addition of calcium hydroxide
D) Addition of sodium phosphate
7. Four different solutions of a single amino acid were titrated, and the pK values of the solute were determined.
Which solution contains an amino acid that would be most likely to stabilize an anionic substrate in an enzyme pocket at physiological pH?
A) Solution 1
B) Solution 2
C) Solution 3
D) Solution 4
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Answers to Sample Questions
1. The progress of Reaction 2 can be monitored by observing what change to the IR spectrum of the product mixture?
A) Appearance of a broad peak at 3400 cm–1
B) Disappearance of a broad peak at 3400 cm–1
C) Appearance of a sharp peak at 1700–1750 cm–1
D) Disappearance of a sharp peak at 1700–1750 cm–1
2. The following kinetic parameters were obtained for the IDO-catalyzed oxidation of Compound 3 by H2O2 in the presence of L-Trp.
Based on this data, what effect does L-Trp have on the reaction?
A) L-Trp oxidizes Compound 3 directly.
B) L-Trp is oxidized instead of Compound 3.
C) L-Trp does not interact with the enzyme.
D) L-Trp inhibits the enzyme.
3. Which experiment can be used to show that Compound 6 is not formed sequentially from either Compound 4 or Compound 5?
A) Conduct the reaction of Compound 4 with Compound 5, and identify the products.
B) Oxidize Compound 4 and Compound 5 with IDO/H2O2, and identify the products.
C) Reduce pure Compound 6 without added catalyst, and identify the products.
D) Conduct the reaction of Compound 2 with H2O2 without added catalyst, and identify the products.
4. In Michaelis-Menten enzyme kinetics, what is the velocity of the reaction when the substrate concentration is equal to KM?
A) ¼Vmax
B) ½Vmax
C) Vmax
D) 2Vmax
5. The radius of the aorta is about 1.0 cm and blood passes through it at a velocity of 30 cm/s. A typical capillary has a radius of about 4 × 10–4 cm with blood passing through at a velocity of 5 × 10–2 cm/s. Using this data, what is the approximate number of capillaries in a human body?
A) 1 × 104
B) 2 × 107
C) 4 × 109
D) 7 × 1012
6. A test for proteins in urine involves precipitation but is often complicated by precipitation of calcium phosphate. Which procedure prevents precipitation of the salt?
A) Addition of buffer to maintain high pH
B) Addition of buffer to maintain neutral pH
C) Addition of calcium hydroxide
D) Addition of sodium phosphate
7. Four different solutions of a single amino acid were titrated, and the pK values of the solute were determined.
Which solution contains an amino acid that would be most likely to stabilize an anionic substrate in an enzyme pocket at physiological pH?
A) Solution 1
B) Solution 2
C) Solution 3
D) Solution 4
Check out this infographic for help with the MCAT Chemistry section:
What is Tested on the MCAT Chemistry and Physics section?
The breadth and volume of material covered on the MCAT, not to mention how long it is, are major challenges in preparing for and doing well on this important exam. The MCAT encompasses information from several of your introductory pre-med courses, as well as the critical thinking and reasoning skills that you have been cultivating throughout your academic career. While the MCAT will undoubtedly be a tough exam, an important first step of MCAT prep is understanding what will be covered in each section.
So, what academic disciplines are covered in the Chemical and Physical Foundations of Biological Systems section—sometimes referred to simply as the “chemistry and physics” section—of the MCAT? Questions included in this section breakdown as follows:
The concepts are combined with scientific inquiry and reasoning skills. The CPBS section incorporates concepts taught in your introductory level chemistry courses and relates these concepts back to biology and physiology.
The chemistry and physics section covers the following foundational concepts:
- Complex living organisms transport materials, sense their environment, process signals, and respond to changes using processes understood in terms of physical principles
- The principles that govern chemical interactions and reactions form the basis for a broader understanding of the molecular dynamics of living systems
The AAMC’s overview of what’s on the MCAT offers a detailed list of the subtopics included within each foundational concept of the Chemical and Physical Foundations of Biological Systems section of the MCAT. The CPBS section’s main subtopics include:
How to Prepare for the MCAT Chemistry and Physics Section
When to start studying for the MCAT will depend on how much knowledge you have retained from your introductory university classes. You will need a solid knowledge base in each of the content areas listed above to excel in the CPBS section. However, this section is about much more than just memorization. Memorization may be step one, but understanding is the crucial second step to contextualizing and making this information usable come exam day.
Knowing how to use chemistry and physics information to solve new problems is the key to a great score on the CPBS section. It asks you to solve problems by combining your knowledge of foundational concepts with your scientific inquiry and reasoning skills. Additionally, you will need to do some basic math without the help of a calculator. Beyond testing your content knowledge, the MCAT will also test your ability to pull relevant information from each passage you read, as well as your understanding of the mechanisms behind the facts you have learned. For example, many students spend days of valuable study time memorizing organic chemistry reactions, when they should really be focusing on understanding the principles behind organic chemistry. True understanding developed through your MCAT reading comprehension will allow you to apply these principles to new problems on the MCAT.
Phase 1: Diagnostic Testing and Review
Before you can design your MCAT chemistry guide, you will need to understand your baseline. To do this, you need to take a full-length MCAT diagnostic test. Don’t worry about trying to ace your diagnostic exam, the goal is just to understand exactly where you stand as you embark on your MCAT preparations.
For your diagnostic, we recommend using the AAMC’s full-length exam. Complete this practice exam in one sitting and, ideally, in an environment that mimics test-day conditions, including timing yourself. Using a diagnostic MCAT will help to ensure that the study schedule you create will effectively address your weaknesses and areas that need improvement. Use your diagnostic test results to guide your MCAT preparations by determining which areas you will need to focus on and approximate how much time you’ll need to prepare for these areas. Only after this is planned out can you determine when you should take the MCAT.
To get started with your chemistry review, create an outline that breaks down each foundational concept that you will need to study. Rather than just writing “study chemistry” on your to-do list, first break each content area into manageable subjects. Use the AAMC’s list of subtopics as a guide to ensure that there are no gaps in your preparation. For example, for the foundational concept regarding how the principles that govern chemical interactions and reactions form the basis for molecular dynamics in living systems, start by focusing one study session on a specific content category, such as the unique nature of water or types of intermolecular interactions. Investigate how each subtopic relates to the bigger picture of its foundational concept. After covering each subtopic by reading your textbook or by reviewing coursework, check your progress by asking yourself the following questions:
Continue reviewing chemistry and physics content until you are confident in each of the main foundational concepts. At the midpoint in your overall study plan, take another full-length MCAT practice test to assess your new baseline. Then it’s time for Phase 2.
Phase 2: Specialized Studying and MCAT Prep Questions
Following this period of review and study, you’ll want to begin working through the MCAT Chemistry questions in this article, MCAT chemistry equations, MCAT physics equations. You may also want to develop an MCAT CARS strategy—practice with MCAT CARS passages and challenging reading to improve your reading and comprehension skills. In our 6-month MCAT study schedule, we recommend reading approximately 1 non-MCAT/-science book each week to strengthen your ability to analyze and extrapolate from new material.
Additionally, if you do well with guidance or simply feel overwhelmed by the road ahead, it may benefit you to enlist the help of an MCAT tutor to help you. Having an expert provide individualized feedback and offer more informed feedback on your performance can be extremely helpful in making sure you don’t overlook your blind spots, which is frankly hard to avoid when you’re working completely alone.
As this phase of your studying progresses, increase both the duration of your study sessions and the ratio of questions to review. We recommend spending at least 70% of your time doing practice question, which will likely involve the use of a question bank like UWorld. Utilize any explanations or performance tracking your chosen question bank offers and be sure to vary your time between timed questions and slower, self-paced sessions, as well as subject-specific and randomized sessions. The more adaptable you are come exam day, the more confident you’ll be when you hit a speed bump.
Remember, the Chemical and Physical Foundations of Biological Systems section of the MCAT is the first section you will face on the test day, and this can be intimidating! While it is true that you will not have to worry about burning out for this MCAT section, your nerves may kick in at this point. You may even experience test anxiety. Practice will ensure that you have the confidence needed to immediately focus and get to work on this first section of the MCAT. Importantly, adequate performance and confidence in this first section will also help to ensure success in later sections. You want to avoid feeling discouraged after the chemistry and physics section, as this can hinder your performance for the remainder of the test day. Confidence and practice are your best friends!
Take a look at our tips for mastering the chemistry and physics section of the MCAT:
Tips for the Chemistry and Physics Section of the MCAT
Tip #1: Understand the Skills Being Tested
When answering MCAT questions, it can be helpful to first identify the question type or the skills being tested. The AAMC has defined four skills that are tested in each of the four MCAT sections:
Tip #2: Prep for Chemistry and Physics Data and Experiments
The AAMC typically tests students with chemistry and physics experiments. This means that you cannot just practice vocabulary and memorize equations. You must be able to apply your knowledge to experiment-style questions. Take some time to learn how to read MCAT graphs, as well, since this section of the MCAT will make liberal use of them and you want to be ready to tackle them quickly. Reading the name of the x-axis and y-axis for graphs, as well as the title and legends for each figure or graph, will help you understand the information being conveyed. Practice identifying independent and dependent variables, as well as controls for an experiment. For every figure or graph that you encounter while preparing for the MCAT, take the time to review them fully to understand all information presented. This practice will ensure efficiency when the test day rolls around. Lastly, if you are working on an MCAT question and you feel that you are missing pertinent information, remember that the missing information will be hidden within the passage and possibly even within the data presented—it’s just a matter of reading between the lines and analyzing the data.
Tip #3: Mimic Test Day Conditions and Brush Up on Your Math Skills
You won’t have access to a calculator on exam day, so as you prepare for the MCAT it’s important that you complete practice questions in conditions that will mimic those of the test day. This means that since you will not have a calculator during the MCAT, don’t practice with a calculator! Solving most chemistry problems requires knowledge of math and a strong understanding of units like m/s, mmol/L, µL., and common prefixes like mono-, hexa-, deci-, centi- and so on. Brush up on math skills involving exponents, scientific notation, and multiplication and division of complex numbers. You will not have a calculator, but you will have access to the periodic table of elements, so be sure you know how to use it. Practice with the version of the periodic table that you will have on the test day, which provides the abbreviated name, atomic mass, and atomic number of each element.
Tip #4: Know Your Units and Equations
Knowing your standard SI units and how to perform unit conversions seems basic, but they are foundational to understanding the context of MCAT questions. When feeling the exam approaching, you can easily start to panic if the answer you get is not among the answer choices. However, a simple unit conversion or a switch to scientific notation may reveal the correct answer. This is why it is important to be able to convert between units and different representations of numbers with ease. Chemistry is all about units, so don’t let these basics trip you up! Similarly, you will need to know many foundational physics equations for the MCAT, including speed (s=d/t), acceleration (a=Δv/Δt), and force (F=m*a) among many others. Be sure to start memorizing and understanding these equations early in your MCAT preparation to ensure that you have ample time to complete this task.
Conclusion
Because the chemistry and physics section are the first section of the MCAT, it is important to know what you are up against and how to build confidence for this first hurdle on the test day. We have outlined the key foundational concepts tested on the chemistry and physics section of the MCAT, what this section will look like, and our top tips for how to start preparing. Use the sample questions and answers within this blog to get an idea of the question format and difficulty that you will face during the MCAT, or to test your skills once you have finished reviewing your coursework. Remember that you need to dedicate a good amount of time to prepare for the chemistry and physics section of the MCAT and that we will always be here to support you in your MCAT journey! You’ve got this, and we’ve got your back!
FAQs
1. What is a good score on the chemistry and physics section of the MCAT? How will I know I am ready to take the MCAT?
Asking this question means you are focusing on an ineffective MCAT study strategy. Focusing on a “good” score that will just get you into medical school is not advised. Instead, aim for the best score that you can achieve on each MCAT section to maximize your medical school options. Getting ready for the MCAT is no small task and it can take months to adequately prepare. How can you gauge if you are ready to take the MCAT? The chemistry and physics section of the MCAT, like each of the four sections, is scored on a scale of 118-132, with the median score set at 125. Take a look at your diagnostic MCAT score and the scores you have been getting on your full-length practice exams. Are you still improving, or have your scores plateaued? Continue to study as long as your MCAT scores continue to improve. If your MCAT score stabilizes, it is a good idea to take the exam, as long as your score range is acceptable to you. When you consistently score within your desired score range at least 3 times in a row, you are ready to take the MCAT!
2. What was the mean score for the chemistry and physics section of the MCAT last cycle?
Last cycle’s matriculating medical school students earned a mean score of 127.8 on the Chemical and Physical Foundations of Biological Systems section of the MCAT, which translates to a percentile rank in the 85th percentile. Therefore, on average, matriculating students earned a score on this section that was the same, or better, than 85% of all students. For a look at mean scores and percentile ranks for the other MCAT sections, take a look at our blog "How Hard is the MCAT?" After you take the MCAT, determine the median MCAT scores for previous admissions cycles at your schools of interest; look at individual section scores as well as the median total score. As you build your school list, included several programs where your MCAT scores give you a reasonable chance of acceptance.
3. My score on the chemistry and physics section of the MCAT is much lower than my scores for the other three sections. Is this ok?
Medical schools interpret your MCAT scores at their discretion. Some may put an emphasis on one section over the others, for example, CARS scores are often prioritized by medical schools. However, generally, a balanced score is better than an imbalanced score. Therefore, it is important to aim to do equally well in all four sections. Consistency across every section shows your ability to think critically and to reason in many different content areas, which is a crucial skill for future physicians. You want to demonstrate that you can apply your reasoning skills to chemistry and physics content, not just biology or psychology. It is also helpful to remember that each section makes up ¼ of your overall MCAT score, so each section is equally important! If you are really struggling, you can look into getting an MCAT tutor to help strengthen your score on this section of the MCAT.
4. Is there specific coursework that I should take to prepare for the chemistry and physics section of the MCAT?
All of the content on the MCAT is covered in introductory courses at most universities. It is important to take these introductory courses to help build your knowledge base and confidence in these areas before taking the MCAT. If you are a non-traditional medical school applicant that did not have the opportunity to take these typical medical school prerequisites, consider taking additional university courses or pursuing a post-baccalaureate program or a special master’s program designed to get you up to speed with the knowledge base you will need for the MCAT. Regardless of your academic path, be sure to leave yourself enough time to thoroughly review each content area on the MCAT. This will be a time-consuming task, but one that is definitely within reach!
5. What are some techniques for memorizing the physics equations I will need on test day?
As you study for the MCAT, you may find that the traditional methods for memorizing equations, such as making flashcards, are not working for you. What else can you try? Here are some additional techniques to consider working into your MCAT preparation: write the equation down several times on a piece of paper until you can recite it out loud without referencing your study materials, complete several practice problems that require the use of the equation, try grouping several equations together by topic to see similarities between equations that you are struggling with and the ones that you have already mastered, ask a friend if they have developed any catchy mnemonic devices to remember equations. Remember, truly understanding an equation will be key in remembering it. For any equations that you are struggling with, go into depth for each part of the equation and work to understand how each part works together. You can also try going back in your notes and reviewing any equations relating to foundational concepts that you learned previously. Knowledge gaps in topics that you have already covered may be hindering your ability to learn new equations.
6. Can I use a calculator during the chemistry and physics section of the MCAT?
You will not be able to use a calculator for this section of the MCAT, which means that it is important that you do not complete sample questions or practice MCAT exams with a calculator. It is important that you set yourself up for success by completing your MCAT preparations under conditions that will mimic those of test day. Use the months leading up to your MCAT to build up your efficiency in doing mental calculations and in doing math by hand.
7. What is a good way to remember formulas?
Make flash cards and focus on units - if you can get the correct units in your answer, you can probably figure out the correct formula.
8. Will I need to know how to draw molecules for the MCAT?
The MCAT is a multiple-choice test and does not contain any free-response questions where your knowledge of how to draw molecules will be tested. The MCAT focuses more on the foundational concepts of chemistry and organic chemistry. That being said, a basic knowledge of molecular structure, and how to draw molecules, will likely come in handy for understanding diagrams provided within the MCAT and in solving multiple-choice questions related to bonding, intermolecular attractions, etc. Similarly, you will need to know how to draw free body diagrams to do force calculations for physics questions, but your diagrams themselves will not be scored.
9. How can I use process of elimination to help me during the MCAT?
The majority of questions that you will face within the MCAT will be passage-based questions. This means that the correct answer must be supported by ideas, or information, within the passage. Use this to your advantage! After reading a passage, identify the central thesis or the author’s main idea. When using process of elimination, look at each answer choice and ask yourself if there is anything within the answer that obviously contradicts what you read in the passage. Eliminate those answer choices. In addition, the correct answer must be supported by the passage, so watch out for answer choices that are beyond the scope of the passage.
10. When should I take the MCAT?
Only take the test when you are ready! More specifically, you want to score in the 90th percentile and do so consistently during your practice tests before you take the real exam.
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