MCAT Biology : Everything You Need to Know

February 9, 2024

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The MCAT determines whether or not you are prepared for medical school. As a result, biology, living systems, and the human body make up a large portion of the MCAT. You cannot achieve a competitive score on the MCAT with a shaky background in these disciplines, especially biology.

While you should devote equal attention and preparation to all subjects included in the MCAT, biology is something that you should focus on. 

As you prepare for the MCAT, ensure that you employ the best strategies to master biology. 

If you are looking for a complete MCAT biology guide, that is exactly what this page is for. We will go through every single piece of information that you need to know about MCAT biology to be able to ace it. Please read on!

MCAT Biology: Everything You Need to Know

Biology is the study of life. Biologists generally investigate living organisms' composition, purpose, growth, origin, evolution, and dispersion. 

Biology is essential because it advances our knowledge of the various levels at which organisms interact and perform their functions.

Thanks to advancements in biology, scientists have produced more food to feed a growing human population. They have also created better pharmaceuticals and disease treatments by better understanding how people may react to environmental change.

Unsurprisingly, biology is heavily weighted on the MCAT. Only the Critical Analysis and Reasoning Skills (CARS) component of the MCAT will not test your biology knowledge.

Sixty-five (65) percent or a total of 39 (out of 59) questions in the MCAT Bio/Biochem section are biology-related.

  • Introductory biology - 65%
  • First-semester biochemistry - 25%
  • General chemistry - 5%
  • Organic chemistry - 5%

Additionally, 3 (out of 59) of the questions in the Chem/Phys Section, or 5%, are devoted to biology.

The Psych/Soc Section follows a similar pattern, with 5% of the questions relating to biology.

Despite the large amount of material to be covered in your biology review, remember that you do not need to be a biologist to succeed in these MCAT sections. 

To be well-prepared for the MCAT, we strongly advise you to study a range of biology subjects.

It can be a good idea to enroll in more than just introductory classes. Advanced courses will help increase critical thinking/scientific reasoning skills. Taking more biology courses in university will help you with your MCAT preparation.

Summary Table of Biology Distribution in the MCAT

MCAT Section

Biology Subject


Number of Questions 

(out of 59)

Biological and Biochemical Foundations of Living Systems

Introductory Biology



Chemical and Physical Foundations of Biological Systems

Introductory Biology



Psychological, Social, and Biological Foundations of Behavior

Introductory Biology



Total Number of MCAT Biology Questions: 45 

Biology Topics to Study for the MCAT

Premed students who did not major in biology or biological science generally fear biology and biochemistry. They worry that they will not succeed and that medical schools would question a student's ability to handle the rigorous academic requirements of medical school based on a subpar biology/biochemistry score.

Do not worry! What's important is knowing the topics that really matter. 

Below is the list of biology topics you must study and master for the MCAT.

8 Tips and Tricks to Ace MCAT Biology

The MCAT biology section can be difficult. However, getting every single biology question correct is achievable. 

A lot of test-takers have done it and so can you. The key is to apply the best and proven tips and tricks that have helped former test-takers achieve a strong MCAT score.

Start Early

Depending on the time you have available to study each day, we advise starting your preparation approximately three to six months before the MCAT test date. This gives you enough time to understand the material without giving you too much extra time to risk forgetting it.

However, ‘early’  may mean different things to some students, as the time you should start your MCAT preparation depends on other obligations and where you are in your MCAT preparation.

Improve Your Scientific Reasoning Skills

While tackling the biology passages on the MCAT, it should be very obvious that you are reading for a specific reason.

You will need to employ your scientific reasoning abilities along with your scientific inquiry talents. 

Apply the ideas you have learned to the appropriate context. The MCAT will require you to use your scientific skills on the day of the exam.

Make Your Own Flashcards

Another tactic to learn biology is to research subjects as soon as you realize you don't understand them. Make a flashcard for each part of the concept you don’t understand. Your weakest subject matter will eventually be organized into a stack of flashcards that you may continually drill into your memory.

If you find creating your own flashcards a little too tricky, you can also use pre-made ones. Most students use them and have benefited from them. In addition, you can choose from paper flashcards and digital flashcards.

To help students like you, we’ve compiled the following resources to help ace MCAT Biology:

Know and Master the Different Organ Systems 

In the biology section, you will be asked questions regarding several organ systems found in the human body. While it is not required to know every detail of each concept, you should be aware of the general purposes of each organ system and how it is organized to carry out those purposes.

You must be able to construct a diagram with full confidence. There are a lot of organ systems in the human body, and studying about 1-2 of them a day greatly helps.

Answer Practice Tests

Without a doubt, taking practice exams will help you improve your score for the MCAT. Not only do they familiarize you with how the MCAT is structured, but these tests also give you feedback on the areas in which you need improvement. 

There are a variety of third-party tests you may take, which are excellent to use when you first start studying. As the test date approaches, about a month in advance, take some AAMC practice exams. 

If your schedule allows, try taking all of the AAMC practice exams as these best represent the real MCAT exam.

Focus on High-Yield Topics

As you study regularly, focus on MCAT biology high-yield topics. Test preparation approaches like spaced repetition and frequent reinforcement are essential for memory retention for subjects like amino acids.

It is crucial to revisit these subjects frequently for long-term and quick recall/retention/memory for test day. 

Do not waste your time on biology topics that will not be tested on the MCAT. Not only are you saving time by being selective in your test prep, but you are also making more space in your memory for topics and concepts that matter.

Learn How to Read Actively

Active reading is genuinely grasping and internalizing the information offered to you instead of merely reading a text passively. When you actively read a passage, you will spend less time returning to it during the test and rediscovering the content.

Start by reading about topics that interest you, even if they are not biology and MCAT-related. 

As you develop the skill of active reading, slowly lean towards materials about health and medicine. This way, you will best prepare for passages you will encounter in the MCAT.

Acquire Reading and Analytical Skills for Graphs, Tables, and Charts

In addition to learning the content you will need for this subject, we advise improving your ability to comprehend graphs, figures, and tables. It is guaranteed that they will appear in any of its four sections on the MCAT

You will have more energy, time, and mental resources for the test's questions if you develop these skills since you can understand them easily and swiftly.

6 Test Days Tips for MCAT Biology 

Aside from the MCAT biology preparation tips we have above; you will want to ensure that the effort you have exerted does not go wasted. Make sure that you're able to tackle MCAT biology questions effectively and confidently. 

Here are some test day tips for the MCAT biology: 

Visualize As You Answer the Questions 

Being able to picture what you are reading about is necessary for understanding the content. In addition, drawing the information (quickly by sketching it) and using it with your outline will help you remember it better when answering biology questions. 

Do not be afraid to draw diagrams if you think it will help you arrive to the correct answer. However, do not spend too much time creating this diagram or you compromise not being able to answer other questions.

Keep the Big Picture in Mind

As you read, consider why the author includes particular details and how those particulars relate to the paragraph as a whole. You can also get a peek at this bigger picture by writing notes about pertinent ideas as you read. 

Apply your analytical and critical thinking skills. Often, you just need to put on your thinking hat to be able to comprehend the questions thoroughly.

Analyze Graphs and Figures 

Aside from long passages, there will be graphs, charts, and tables on the MCAT; that is a fact. These graphs and charts tend to support what the passages are trying to convey. 

Do not lose patience if it takes some time to understand the figures from one passage. 

There isn’t much new material that the AAMC can give you that you have not already seen once you have done this for every MCAT biology passage you have been given.

Read the Questions First 

If you are already acquainted with the subjects covered in the questions, you can read the material more quickly and effectively. 

Before working on the section, read the question stems from first to last (not the answer options), looking for and highlighting any words or phrases that refer to important passage content.

This technique also saves you time as you do not have to focus too much on sentences and paragraphs that do not relate to the questions being asked. You can also try the skimming and scanning technique.

Paraphrase, Translate, and Eliminate

Give the questions your own interpretation by rephrasing it in your own words. Then, return to the passage, locate, read, and paraphrase the essential information. Next, think about what the appropriate response will require while keeping the question in mind. 

As you look over the choices, use the elimination procedure. Do not linger too long on questions that you find really difficult. If you encounter an extremely challenging question, try to finish the other, more straight forward questions first.

Keep an Eye on the Time

On the MCAT, time management is crucial. The biology questions are difficult and might drag on for a while. In addition, some of the passages might be uninteresting, and you might find it challenging to focus on something you find boring. 

However, it is important to avoid concentrating too much on the subject. 

Remember that you only have 95 minutes to finish each MCAT section – except for the CARS section, where you have only 90 minutes.

MCAT Biology Preparation Resources

We advise you to use the various MCAT biology prep tools as you study for the exam. They will undoubtedly help you get a strong score for the MCAT. Here are a few examples:

Additional FAQs – MCAT Biology

How can I Improve My MCAT Bio/Biochem Score?

You can improve your MCAT bio/biochem score by solidly understanding amino acids. Questions about them will be present on the MCAT, for certain. Study and master the concept of amino acids, including their structure and properties. 
Another way to improve your MCAT bio/biochem score is to solidify your background knowledge about the different organ systems in the human body and how they function. Drawing concept/idea maps between topics can be beneficial to better understand how concepts are related.
As a future doctor, these concepts are essential, and you should be able to answer questions about them easily.

Is Biology Needed for the MCAT?

Yes, your biology knowledge and skills are required in the MCAT. You cannot ace the MCAT and get a solid score if your biology knowledge is subpar. 
Aside from chemistry, most questions in the MCAT will require your MCAT biology background. Therefore, make sure you spend adequate time and attention studying biology for the MCAT.

What Percentage of the MCAT is Biology?

Biology covers 20% of the MCAT
It means that out of the 230 questions, 45 questions are biology-related. 
There will be 39 biology questions in the Bio/Biochem section, 3 in the Chem/Phys section, and 3 in the Psych/Soc section.

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