The AP Biology test is one of the most popular AP science tests taken annually, if not one of the top 5 AP tests overall. And it isn’t hard to see why that would be the case! Biology is an approachable subject that is less mathematically intensive than its other core science brethren (physics and chemistry). For many students, biology is the science that simply makes the most sense. Because of this, some students even opt to self-study for this AP exam (whether this is the right option for you will be discussed later in this guide). 

This guide is dedicated to the fundamental concepts behind the AP Biology exam, including the core concepts required to successfully navigate the exam and a discussion of whether the exam is suitable for you. This guide is not a comprehensive review of content, though there will be a succinct list of concepts and some tips on how to approach studying for the AP Biology exam.


The AP Biology exam is designed to be the equivalent of the first semester of college-level biology. As someone who majored in biology in college, I can attest that this test truly covers a brunt of a freshmen introductory biology course (though not as deeply). Because of this, the AP Biology exam focuses on core fundamentals of biological science. Like every AP science exam, it is going to test both content mastery and understanding of the scientific process, including data interpretation and model analysis. 





% of Total Score

Section 1: Multiple Choice

1 hr 30min

60 questions

50% of score

Section 2: Free Response

1 hr 30min 

6 questions

50% of score

There is a small 10-minute break between the two sections. I would advise to quickly use the restroom, sharpen your pencils, or whatever else you need during this time. Time can be rather tight during the AP Biology exam, especially during the free-response portion. Use this time wisely.


If you look at College Board’s breakdown of the AP Biology exam, they claim that it tests 6 core skills: Concept Explanation, Visual Representation, Questions and Methods, Representing and Describing Data, Statistical Tests and Data Analysis, Argumentation. These are fancy names dedicated to some basic tenets of science. Below, I have simplified them into 3 basic groups.


In any science, there are ways for scientists to reenact/explain natural phenomena. The AP Biology exam seeks to test your understanding of the scientific processes that the models seek to display. This can be anything from a science experiment set up to a visual representation of cells in specific situations.

A good example of this would be an ELISA model: This is a common biological protocol that uses antibody-antigen bindings to detect a desired molecule or identify an unknown agent. When provided with such a model, you may be presented with a series of wells along with information regarding the well-wall coating, the primary antibody, and the presence of an unknown substance. Given this information, it would be necessary for you to identify what type of ELISA must be performed and what the next steps would be. You would also want to ask yourself: “What more can I deduce from the information given?” 


The data analysis questions are probably one of the most important aspects of AP Biology. This is what truly signifies you understand the inherent interdisciplinary nature of biology. What I mean by this is that these sections are where your knowledge of algebra or chemistry will be most useful.

Take, for example, a question which presents to you a table showing 2 enzyme kinetics properties, Km and Vmax, with and without the presence of an inhibitor. Your first instinct in such an example should be to recall the Michaelis-Menten equation. It also requires you to understand from a chemical standpoint why a Vmax exists (why an enzyme reaction would not continue to speed up?) 

In analyzing data, it is necessary for us to be able to deduce relevant information. In our example above, you should be asking questions such as “What form of inhibition am I seeing?” and “How would this be depicted graphically?”


This segment is your basic understanding of science, particularly regarding the important of hypothesis, corroboration, and conclusion. For most attempting the AP Biology exam, a strong background in scientific inquiry is fairly commonplace, so I will not delve too deeply into this section. 

However, I will note here that there is some tricky mathematics in the AP Biology exam. Notably, biology requires you to know how to perform chi-square tests (a statistical technique useful for comparing 2 variables with multiple possible values; check the link for an in-depth explanation).



There are 9 units of content to the AP Biology exam. Below, I have listed the categories and their percentage breakdown in the current rendition of the exam as specified by College Board. Note that not all units are equal. However, this does not mean that any section can be ignored or that you can have “weak subjects” for the exam.


Questions derived from this unit focus on the fundamental biochemistry of biology. The role of water is particularly emphasized as it is an important part of many biological processes. It is also important to have a grasp of the 4 macromolecules which constitute all life on Earth: proteins, carbohydrates, lipids, and nucleic acids. In general, you should know the chemical structures and interactions macromolecules are capable of (i.e. proteins are bonded together by peptide bonds) and the properties that each display (i.e. lipids tend to be hydrophobic, which directly plays into their important role of membrane compartmentalization).


If you are reviewing for the AP Biology exam, that the cell is important to biology should probably be a given. Safe to say that College Board agrees. This unit contains many different components. Firstly, you must be aware of the cell organelles, including features unique to animals or plants. You should also have a rough idea of how prokaryotes are structured and why they are different from eukaryote cells. 

This section also tests your understanding of how cells regulate its internal homeostasis. Once again, our universal solvent (water) becomes important, as it is the key player in osmosis and tonicity. Furthermore, you should know that cell membranes are semi-permeable, and understand how they can “pump” materials in and out of the cell.


In my opinion, this is one of the first units that many students may struggle with. Usually, students can understand enzyme kinetics relatively easily, as it uses elementary chemical knowledge to help elucidate how enzymes boost metabolic efficiency. However, when it comes to convoluted processes such as photosynthesis and cellular respiration, the overwhelming number of steps can often daze the student. In their stress, I noticed many students try to memorize every step of cellular respiration, memorizing the enzymes like phosphofructokinase without taking the time to understand why each step is important. 

For this unit, I would heavily recommend taking the time to appreciate the pure biochemical marvels that are central to all life. Grasping why each step is important and seeing the pattern in its naming system will facilitate much of the memorization and make it much more bearable. If you plan on majoring in biology for college, I promise that this technique will save you much time in the future.


Eukaryotes, by their nature of being multi-cellular, must often specialize into various cellular forms. In the human body, we have an astounding diversity of cell types: myocytes, astrocytes, B cells, T cells, neurons, epithelial (and the list goes on). So, the question is: how do these cells signal to other cells what the body needs?

This unit focuses on the idea of cell communication mediated through cell signaling. In this section, you must be able to explain how hormones can be sent from one cell to another, how the receiving cell responds to this signal, how the original cell is alerted that homeostasis has been reached (biofeedback loops). This overall concept is summarized by the notion of signal transduction. 

This concept will be useful in also understanding how the cells regulate their cell cycle, and in doing so continue the loop of replication necessary to reproduce somatic cells (mitosis).

UNIT 5: HEREDITY (8-11%)

As a direct continuation of the discussion on mitosis, this unit will discuss meiosis. In this unit, you will have to understand the cellular basis for why DNA recombination occurs during gamete formation. You will also be responsible for understanding both Mendelian and non-Mendelian inheritance, which is key to a comprehensive genetics background. 


If cellular energetics is the unit that most students struggle with, this unit is the one I see most students feel confident in but make many crucial mistakes. And with a unit like this, mistakes can be costly. In this unit, you must understand the structural basis for DNA/RNA, how the double helix formation was discovered, why it is crucial to coding of our genetic blueprint, and how the structure contributes to the Central Dogma. You should be able to list the steps from DNA to protein, including key accessory enzymes. 

Furthermore, you will need to explain how genes can be regulated in the body in response to biological changes. This is associated, of course, with how the DNA blueprint itself can be changed and by what factors (mutations and mutagenic causes). 


Despite its rather high exam content percentage, I personally think this section is rather easy. You need to be able to discern the various types of selection and be able to explain phenomena regarding the Hardy-Weinberg. This section also deals with concepts related to evolution and how populations can change over time; how these divergences have led to the current diversity of life on Earth today. 

UNIT 8: ECOLOGY (10-15%)

This section is related mostly to how energy flows within ecosystems. Thankfully, we do not need to apply advanced thermodynamics to this understanding of biologically energy. However, it is important to understand the cyclical nature that is at the core of ecological balance and synergy. For example, there should be an understanding of the logarithmic relationship between predator and prey populations (why might that be?). 



One of the major reasons why any student would consider taking any AP exam is the potential for it to count as college credit. Certainly, AP Biology is no exception to this rule. The AP exams are usually the most well-accepted form of college credit (the IB system often works as well and community college acceptances differ school by school). 

However, important to note is that if you are planning on majoring in biology or any biologically related field, you are likely not going to be able to use the AP Biology exam as a substitute to skip introductory biology courses (this was the case at my alma mater). If this is the only reason you are pursuing the AP Biology exam, I would not recommend taking the AP Biology exam (there are better ways to spend the weekend).


Even though AP Biology may not necessarily translate to a college credit for you, it does denote to colleges that you are serious about your academics. AP exams are recognized as difficult tests and they are used as a form of benchmark for college application reviewers. A lot of the skills tested in these exams are relevant in college and reviewers understand that AP test takers have higher chances of doing well academically in college as well. 


As I mentioned earlier, the AP Biology exam does a swell job at covering core concepts covered in first-year college courses, albeit slightly truncated and less in-depth. This is a major reason why many seeking science degrees in college will still take AP Biology exam. 

If you’re looking into the pre-med path, this test also utilizes a lot of the same test-taking skills relevant for your MCAT, though I wouldn’t use that knowledge as the basis for taking this test.


As I noted in the introduction, the AP Biology exam is by far one of the most popular AP tests, particularly due to the popularity of the subject in general. However, I would caution students from thinking that this means the test is easy. Despite the 260,000 students who took the test in 2019, only 18,800 (or 7.2%) received a score of 5 and only an additional 22% received a 4. A 30% chance of getting a 4 or 5 is not horrible, but it is a testament to the preparedness that this test requires and should not be taken lightly! 

However, the AP Biology exam is extremely fair and consistent. It is easy to know what to expect because the contents of the exam are so darn consistent. In fact, each free-response question has distinct categories of skills they are seeking to test. Because of this, AP Biology is one of the exams that can be prepared for with guided, planned studying. As such, I believe that the AP Biology exam can be rated as an average difficulty exam.


AP Biology exam is collectively around 3 hours and 30 minutes including the breaks, and introduction/ending readings by the proctor. 

Section 1A: Multiple Choice (text only) 

1 hour 30 minutes | 60 questions | 50% of score

This section contains multiple choice questions that are not linked to any passages and are standalone questions. They test key chemical concepts and usually have easier math to be able to solve questions quickly. This section is tremendously helped by the process of elimination. This is because usually they are some bad answers that can often be immediately crossed out. 

Section 2A: Free Response Written

1 hour and 30 minutes | 6 questions | 50% of score

There are 6 questions to the AP Biology exam: 2 are longer questions worth 8-10 points and 4 are worth 4 points each. Listed below are going to be the 6 questions types that will be tested in the AP Biology exam as outlined by College Board. With every question, it is critical that students justify their answers with biological explanations of their reasoning. 


This question is looking to see if a student understands the biological concept, understand what the data is demonstrating, and from it make reasonable conclusions to validate or invalidate the hypothesis. They may have graphs in question but will not require students to make graphs themselves. Usually, these questions have expositional passages to help provide further details to answer the question.


This problem is largely the same as the first one. The major difference is that it will require students to make a chart or graph of some sort, and thus can be more difficult to answer. 


This question is specifically related to a biological experiment protocol. It will test the student’s knowledge of specific protocols and how to perform them. 


Conceptual analysis questions are usually the most straight forward, asking about specific biological processes. These questions are usually the ones students have the least trouble with.


This question will have some form of visual aid from which the student must extract information out of. A standard example that College Board might use is a pedigree chart. In this case, it would be necessary to determine if the hereditary trait is recessive/dominant and autosomal/sex-linked.


While this question also uses visual aids much like the previous question, the importance of this question is that it tests specifically what individual data points mean. This question will want you to make conclusions about the results of an experiment/data sample using your biological knowledge



As far as we can tell (meaning as far as College Board has announced for the upcoming year), the test will remain consistent to its previous years. This is good news as we will have standards from the previous year to compare to!

Do not fret. If any changes do occur, we will make sure to update this guide as soon as we can.


One of the most common things I used to hear from students is around April, they will express a desire to take the AP Biology test. They will buy a prep book, hoping they have enough time to cram in all the info they need. And in fairness, some indeed do succeed in this venture. However, for the vast majority, this strategy will end in disaster.

I want to emphasize that it is so much safer and more consistent to slowly build up your biological knowledge over the course of many months. Yet, if you must insist on efficiency and had only crammed for all your tests thus far, I will heavily recommend you start studying at least 2 months before the exam. 

Also, study smart and work less. If you have a clear game plan with a schedule for content review and practice tests, you will flourish. The AP Biology exam, as with any AP test or really any standardized test, can be prepped for with practice. Prioritize early review of concepts which you feel you are weak in, then go on from there.


  1. Check your mastery: Quickly skim through a diagnostic test or some online source of “practice problems” and see what concepts are giving you a difficult time. If you are struggling with something, identify whether it is something that can be quickly fixed or needs more work
  2. Work on your weaknesses: Just one missed FRQ can potentially spell disaster for your chance of getting a 5 in the AP Biology exam. It is impossible to guess what questions will be asked on the test, and if you concede on weak points, you will set yourself up for failure. Instead, fix your weaknesses and turn them into strengths. Mastering difficult subjects (such as buffers or radioactivity) can really distinguish your score from the median. 
  3. Focus initially on content review: This is a tip that is unique to biology. Even with history, I rarely recommend you focus too much on reviewing details, but biology is all about the details. In fact, there are a lot of things in Biology that simply must be memorized when learning from an introductory level. Things like STOP codons and taxonomic phyla are non-intuitive and should be given the time to sink into long-term memory (Long-term potentiation is very important to biology!) 
  4. Know general ideas: While it may be important to know the STOP codons simply due to their critical importance in protein-production regulation, I heavily doubt the AP test will expect you to memorize the whole codon table. I didn’t have to do it in college so neither should you really. Rather, what the AP Biology exam is looking to test is your ability to identify and speak on core fundamentals of biological processes. If you are able to explain how codons work within the context of ribosomes, tRNA, and mRNA, then you are in good shape.
  5. Practice problems: this cannot be emphasized more. It is the single most important part of succeeding. Practice, practice, practice!
  6. Look at old exam questions: very important to also see what the answers are, and note important parts of the answers that you are missing. See how you can succinctly justify your answers in the free-response to save you as much time as possible


I am a tutor for TutorNerd, so I may lean towards pro-tutor. Even then, I will tell you that this question is difficult to answer for biology. Unlike chemistry or physics, biology is not something that can be easily learned if a tutor helps guide you through the process. Instead, biology is a cumulative science, inherently interdisciplinary. It requires the student to continue working outside of class to build their knowledge base and reinforce it. A tutor cannot fix that. 

Here is what a tutor can help with though. Tutors help the student understand how to apply their knowledge to questions. Many students will have no problem reciting their memorized knowledge, but the first question which tests their depth of comprehension and their knowledge falls apart. Contrary to the biology haters, biology is not a science of memorization alone: it is an applied science. 

What I am getting at is that tutors guide the student with their understanding of what the AP exam is looking for. They know how to guide students so that they do not waste their time studying low yield concepts and focusing the student’s time on the most critical concepts. Tutors can help their students understand how to structure their answers in free responses to maximize their chances of obtaining points. 

So, if you need help with the application aspects of biology, then a tutor really has some potential to help. If it’s simply for content review, even the best tutors will be meaningless unless you are willing to review and reinforce.


A good question. My answer would roughly be “yes (?)” What I mean by this not-so-confident answer is that this depends on a wide gamut of factors. The most important questions to ask yourself are the following:

  • Can you stay on track without a course or grade motivating you?
  • Do you have a strong enough background in biology to grasp difficult concepts?
  • Are you experienced enough with AP tests to be able to handle FRQs without the help of a teacher?

If your answer was no to any of these, then I would consider taking the course at school. If your only no answer was to the third question, then you might be an ideal candidate for a tutor! You can get the assistance you need with the format of the test from the tutors and save yourself a lot of time. 

In the end though, I have found that a good chunk of students does not have the background in studying or biology to challenge the test alone. So, if you’re on the fence about it and do not have absolute confidence in yourself, take the course.


Each section of the AP Biology exam is worth 50% of the overall test points. There are 60 multiple choice questions, which constitutes ½ of the test. This means that each question is worth approximately .83 points on the overall score. There are also 2 long-responses and 4 short-responses in the free response sections. Long-responses are 8-10 points each, short-responses are 4 points each. This means we will have 32-36 points in the free-response section. Those ~35 points are weighted to equal half the overall exam points.  

In order to receive a score of 5, you will need ~70 overall points and around ~60 to earn a 4. Note that you should always, 100%, absolutely aim for at least a 4. A 3 or below is not accepted as college credit. 


The 2021 AP Biology exam is scheduled for May 14, 2021 at 8:00 AM local time.

Students with conflicts or emergencies can request an exception testing window in June. A request must be made through the College Board for emergencies such as exam and class conflicts, athletic events, or illness. Alternate forms of the test are developed for late testing students. See here for more about AP exam dates.


AP exam fees are payable directly to your school, and are generally $94 per exam for domestic exams in the U.S, U.S territories, or Canada. For exams taken outside the United States through the College Board, the exam fee is $124 with the exception of DoDDS schools. There is a College Board fee reduction program of $32 dollars per exam if a student is eligible. To be eligible, a student or family must be receiving benefits from a federally subsidized program such as food stamps, subsidized housing, or other types of benefits. A student who is homeless or an orphan also qualifies for a reduction. Students in programs such as the schools CEP program or with family incomes below the 185% poverty level are also eligible. If a student qualifies for a fee reduction, the school will also forfeit the $9 dollars rebate per exam, setting the final reduced fee at $53 per exam. See here for more about AP fees.


If you are attending a high school that offers AP classes and exams, you must register through your school. Online registration is not permitted for AP exams. There are usually no prerequisites to sign up for this exam, but often schools require you to take introductory high school biology prior to taking its AP course.

For information about the AP exam you can talk to your biology teacher or the designated AP coordinator at your school. Every school administering AP tests has a special coordinator responsible for ordering the exams and collecting the fees—check with your counselor or your school's "College and Career Center".

If you are homeschooled, or attending a school which does not offer AP classes or tests, you can arrange to take the test at another school.  To go this route, you must contact the AP program yourself no later than March 1st of the year that you are planning to take the exam. You will receive the names of local participating schools willing to test outside students and the names of their AP test coordinators. 

The contact information for the AP program is:

AP Services 888-225-5427

International callers 212- 632-1780

Fax 610- 290- 8979


I think that the AP Biology exam has a lot to offer. For those wanting to get a head start in how to approach college-level studying, the AP Biology might be the best example. But, remember that the AP Biology is popular for a deceptive reason: it is not the easiest science exam. You must be disciplined and work hard, just as you would for the AP Physics C or AP Chemistry exams.  

If you are serious about challenging the test, then follow the game plan listed above. And if you need the extra help, TutorNerd has got your back. Good luck, students! May you receive the 5 you deserve.