Orientation - Cracking the AP Biology Exam

Cracking the AP Biology Exam




So you’ve just spent the better part of a year in an advanced placement biology course. And what have you learned? Biology, sure. But what kind of biology?

In theory, you’re midway through the equivalent of a college-level biology course. However, high school courses vary, to say the least. Sometimes you get a great teacher, sometimes … you don’t. The Advanced Placement Biology Exam is a way to determine if the course you’ve taken is up to par: Have you really learned a year’s worth of college-level biology?

That’s what the AP test is intended to measure. You take it so that colleges can determine if you’ve mastered the material that the average college freshman learns in his or her introductory biology course. If so, you’ll be eligible for college credit, advanced standing, or both, depending on the college. Different colleges have different policies, so make sure you find out from the colleges you intend to apply to exactly what their policies are.

What if you’re not enrolled in an AP course? Provided you’ve seen the same topics as those who are enrolled in such a course, there’s no reason why you shouldn’t consider taking the AP Biology Exam. However, before you sign up, check with your biology teacher. He or she is in a much better position to determine if you’ve actually done college-level science this past year.


The AP Biology Exam is written by ETS, the Educational Testing Service. These are the same folks who bring you all your standardized tests, from the PSAT and the SAT to the rest of your AP subject tests. How do they go about it?

A committee of university and high school teachers, along with ETS, determines the content and format of the AP exam. Why should you care about ETS? Well, you shouldn’t. But you should care about how they write the test, which is extremely important when it comes to our approach.


There are basically two ways to prepare for the AP Biology Exam:

  • Know absolutely everything about everything. This is ETS’s way. Bad idea.
  • Review only what you need to know, and tackle the test strategically. This is The Princeton Review’s way—and the best way to improve your score.

Rather than trying to teach you everything there is to know about biology, we at The Princeton Review focus on test-taking strategies. Naturally, we’ll review some hard science as well. But rather than getting bogged down in the details, we’ll focus on the biology you need to know for the test, explaining and highlighting key concepts along the way. But who are we and how do we know so much about what’s important for the AP Biology Exam?

The Princeton Review is the nation’s fastest growing test preparation company. We’ve been at it for more than 25 years, preparing students for standardized tests by showing them how to beat ETS at its own game. Our insight into the AP Biology Exam is the fruit of intensive analysis of heaps of AP exams. For you, this translates into a relatively painless, sure-fire approach to beefing up your AP score.

In this book, we’ll show you how best to take the AP Biology Exam because we know exactly how it’s put together. By understanding how the test is written, we’ll be able to help you outfox the test writers in three ways:

  • by reviewing only the biology you need to know for the test
  • by giving you simple, straightforward strategies for answering multiple-choice questions and for writing essays
  • by focusing on the recurring themes for the AP Biology Exam

By the time you finish this book, you’ll have both the science and the strategies you’ll need to beat the AP Biology Exam.


Fortunately, we’ve already done the groundwork for you. We know exactly what ETS likes to test and how it tests it. The College Board, which administers the test, has put together a list of the topics covered on the AP Biology Exam, as well as a breakdown of the frequency with which they appear on the test.

The AP Biology Exam covers three major areas:

  • Molecules and Cells
  • Heredity and Evolution
  • Organisms and Populations

These three areas are further subdivided into major topics. By the way, the percentages given below will give you a rough idea of the percentage of questions from each category that will appear on the test. For instance, since 10 percent of the test concerns cells (see below), you can expect that about 10 percent of the multiple-choice questions—10 questions altogether—will deal with cells.

Here, then, is the breakdown:

1. Molecules and Cells (25%)

A. Chemistry of Life (7%)

• Organic molecules in organisms

• Water

• Free-energy changes

• Enzymes

B. Cells (10%)

• Prokaryotic and eukaryotic cells

• Membranes

• Subcellular organization

• Cell cycle and its regulation

C. Cellular Energetics (8%)

• Coupled reactions

• Fermentation and cellular respiration

• Photosynthesis

2. Heredity and Evolution (25%)

A. Heredity (8%)

• Meiosis and gametogenesis

• Eukaryotic chromosomes

• Inheritance patterns

B. Molecular Genetics (9%)

• RNA and DNA structure and function

• Gene regulation

• Mutation

• Viral structure and replication

• Nucleic acid technology and applications

C. Evolutionary Biology (8%)

• Early evolution of life

• Evidence for evolution

• Mechanism of evolution

3. Organisms and Populations (50%)

A. Diversity of Organisms (8%)

• Evolutionary patterns

• Survey of the diversity of life

• Phylogenetic classification

• Evolutionary relationships

B. Structure and Function of Plants and Animals (32%)

• Reproduction, growth, and development

• Structural, physiological, and behavioral adaptation

• Response to the environment

C. Ecology (10%)

• Population dynamics

• Communities and ecosystems

• Global issues

In addition to the outline above, we have recently seen a few minor content-related adjustments to the examination. Although we have already included the following content in our comprehensive subject review, it has not previously been seen in questions on the AP Biology Exam. You may now see questions requiring familiarity with representative organisms from the three domains: Bacteria, Archaea, and Eukarya. In addition, more emphasis may be placed on identifying the distinguishing characteristics of each group of phylogenetic classification (domains, kingdoms, and the major phyla and divisions of animals and plants). Other than these minor updates to material tested, there are no major changes in the overall concepts. Furthermore, the distribution of questions relating to each of the topics taught in the course also remains unaffected.

This might seem like an awful lot of information. But for each topic, there are just a few key facts you’ll need to know. Your biology textbooks may go into far greater detail about some of these topics than we do. That’s because they’re trying to teach you “correct science,” whereas we’re aiming to improve your scores. Our science is perfectly sound, it’s just cut down to size. We’ve focused on crucial details and given you only what’s important. Moreover, as you’ll soon see, our treatment of these topics is far easier to handle.


The AP Biology Exam is three hours long and is divided into two sections: Section I (multiple-choice questions) and Section II (free-response questions).

Section I consists of 100 multiple-choice questions. These are further broken down into three parts: (1) regular multiple-choice questions, (2) matching questions, and (3) questions dealing with experiments or data. ETS gives you 80 minutes to answer all 100 of these questions.

Section II involves free-response questions. You’ll be presented with four free-response questions touching upon key issues in biology. You’re given a 10-minute reading period followed by 90 minutes to answer all four free-response questions.

If you’re thinking that this sounds like a heap of work to try to finish in three hours, you’re absolutely right. Here’s how it breaks down: You have roughly 45 seconds per multiple-choice question and 22 minutes per free-response question. Gulp. How can you possibly tackle so much science in so little time?

Fortunately, there’s absolutely no need to. As you’ll soon see, we’re going to ask you to leave a small chunk of the test blank. Which part? The parts you don’t like. This selective approach to the test, which we call “pacing,” is probably the most important part of our overall strategy. But before we talk strategy, let’s look at the different types of questions in the first section of the test.


There are basically three parts to the first section:

  • Part 1—contains regular multiple-choice questions
  • Part 2—is made up of matching questions
  • Part 3—consists of multiple-choice questions dealing with an experiment or a set of data

Part 1

Part 1 of the AP Biology Exam consists of about 58 run-of-the-mill multiple-choice questions. These questions test your grasp of the fundamentals of biology (or so ETS likes to think). Here’s an example:

22. If a segment of DNA reads 5´-ATG-CCA-GCT-3´, the mRNA strand that results from the transcription of this segment will be

(A) 3´-TAC-GGT-CGA-5´

(B) 3´-UAC-AGT-CAA-5´

(C) 3´-TAA-GGU-CGA-5´

(D) 3´-TAC-GGT-CTA-5´

(E) 3´-UAC-GGU-CGA-5´

Don’t worry about the answer to this question for now. By the end of this book, it will be a piece of cake. The majority of the questions in part 1 are presented in this format. A few questions may include a figure, a diagram, or a chart.

Part 2

The second part is slightly different. In part 2, you are asked to match lettered portions of a diagram or a list to numbered statements. This “matching” exercise usually tests your knowledge of different structures. Let’s look at an example:

Questions 63–66

(A) Thyroid

(B) Parathyroid

(C) Hypothalamus

(D) Pancreas

(E) Adrenal cortex

63. Secretes hormones that regulate plasma glucose levels

64. Secretes aldosterone

65. Regulates the basal metabolic rate in the body

66. Secretes gonadotrophic releasing and inhibiting factors

Again, don’t worry if you don’t know the answers yet. We just want to show you what the questions look like. You’re asked to match the numbered questions to the lettered organs above. Sometimes you’ll be given a group of questions, all of which refer back to a diagram or an illustration. You’ll see six to seven of these groupings on the test.

Part 3

The last part of the first section also consists of multiple-choice questions, yet here you’re asked to think logically about different biological experiments or data. Here’s a typical example:

Questions 99 and 100 refer to the following diagram and information.

To understand the workings of neurons, an experiment was conducted to study the neural pathway of a reflex arc in frogs. A diagram of a reflex arc is given below.

99. Which of the following represents the correct pathway taken by a nerve impulse as it travels from the spinal cord to effector cells?

(A) 1-2-3-4

(B) 6-5-4-3

(C) 2-3-4-5

(D) 4-5-6-7

(E) 7-6-5-4

100. The brain of the frog is destroyed. A piece of acid-soaked paper is applied to the frog’s skin. Every time the piece of paper is placed on its skin, one leg moves upward. Which of the following conclusions is best supported by the experiment?

(A) Reflex actions are not automatic.

(B) Some reflex actions can be inhibited or facilitated.

(C) All behaviors in frogs are primarily reflex responses.

(D) This reflex action bypasses the central nervous system.

(E) Reflex responses account for a large part of the total behavior in frogs.

You’ll notice that these particular questions refer to an experiment. In part 3, the experiments, like this one, usually require a little more than just the basics of biology. ETS claims that the questions in part 3 test your ability to integrate information, interpret data, and draw conclusions from the results. More often than not, common sense and logical deduction are a lot more effective here than is “strict science.”


This section of the test consists of four free-response questions—the essays. The questions are usually divided into parts and vary in difficulty. In this section, the test writers are testing your grasp of the major concepts and themes in biology rather than your ability to memorize facts.

Remember the three major areas we said ETS likes to test? Well, one question will come from area 1, Molecules and Cells, another question will come from area 2, Heredity and Evolution, and two questions will come from area 3, Organisms and Populations. The trend on the AP test is to focus on themes that crop up time and again in a typical AP biology course.

Take a look at the themes put together by the AP Biology Development Committee:

  • Science as a Process
  • Evolution
  • Energy Transfer
  • Continuity and Change
  • Relationship of Structure to Function
  • Regulation
  • Interdependence in Nature
  • Science, Technology, and Society

Now let’s look at a sample free-response or essay question:

1. Enzymes are biological catalysts.

a. Relate the chemical structure of an enzyme to its catalytic activity and specificity.

b. Design an experiment that investigates the influence of temperature, substrate concentration, or pH on the activity of an enzyme.

c. Describe what information concerning enzyme structure could be inferred from the experiment you have designed.

Notice that this question has three parts. Part a tests one of the themes from the list: the relationship between structure and function. Part b asks you to design an experiment based on your knowledge of enzymes. Part c refers back to your experimental design and asks you to interpret your results and draw inferences from it. This section tests not only your knowledge of biology but also your organizational and writing skills.

Now that we’ve had a peek at the science you’ll need to know and the structure of the test, let’s look at the strategies that will help you ace the AP Biology Exam.


We mentioned earlier that our approach is strategy-based. As you’re about to see, many of these strategies are based on common sense—for example, using mnemonics like “ROY G. BIV.” (Remember that one? It’s the mnemonic for red, orange, yellow, green, blue, indigo, violet—the colors of the spectrum.) Others are not so common-sensical. In fact, we’re going to ask you to throw out much of what you’ve been taught when it comes to taking standardized tests.

There are eight strategies that we’ll ask you to apply come test time:

  • Strategy 1: Pace Yourself
  • Strategy 2: The Three-Pass System
  • Strategy 3: Process of Elimination
  • Strategy 4: Aggressive Guessing
  • Strategy 5: Word Associations
  • Strategy 6: Mnemonics
  • Strategy 7: Identify EXCEPT Questions
  • Strategy 8: The Art of the ETS Essay

Let’s take a look at the Princeton Review approach.


When you take a test in school, how many questions do you answer? Naturally, you try to answer all of them. You do this for two reasons: (1) Your teacher told you to, and (2) if you left a question blank, your teacher would mark it wrong. However, that’s not the case when it comes to the AP Biology Exam. In fact, finishing the test is the worst thing you can do. Before we explain why, let’s talk about timing.

One of the main reasons that taking the AP Biology Exam is so stressful is the time constraint we discussed above—45 seconds per multiple-choice question and 22 minutes per essay. If you had all day, you would probably do much better. We can’t give you all day, but we can do the next best thing: We can give you more time for each question. How? By having you slow down and answer fewer questions.

Slowing down, and doing well on the questions you do answer, is the best way to improve your score on the AP Biology Exam. Rushing through questions in order to finish, on the other hand, will always hurt your score. When you rush, you’re far more likely to make careless errors, misread, and fall into traps. Keep in mind that for every wrong answer choice you pick in Section I, you lose one-quarter of a point. Blank answers, on the other hand, are not counted against you.

By now you’re asking yourself, “How do they know this works?” Don’t take our word for it. We’ll walk you through an example to prove our point. But before we do so, let’s take a look at how the AP Biology Exam is scored.

The AP Translation Game

The maximum number of points you can earn on the AP Biology Exam is 100 points for the multiple-choice questions in Section I and 40 points for the four essay questions in Section II. These “raw scores” are translated to “composite scores.” ETS has set up the test so that Section I, with its 100 questions, counts for 60 percent of your overall grade, while Section II, with its four essays, counts for only 40 percent of your grade. These composite scores are then further translated to numbered grades ranging from 1 to 5. Here’s how it’s done.

(Raw score for Section I) = (Number answered correctly)

Next, ETS takes that raw score and converts it to a composite score by multiplying it by 0.75:

(Composite score for Section I) = 0.75 × (Raw score for Section I)

If you got every question right on this portion of the test, you would have a raw score of 100. The highest composite score, therefore, is 75 (i.e., 100 × 0.75 = 75).

For Section II, you can earn up to 10 points for each essay question for a total of 40 points:

(Raw score for Section II) = (Points for Essay 1) + (Points for Essay 2) + (Points for Essay 3) + (Points for Essay 4)

Your raw score is then multiplied by 1.5 to yield a composite score:

(Composite score for Section II) = 1.5 × (Raw score for Section II)

If you wrote perfect essays, you would get the perfect raw score of 40. The highest number of points you can get, therefore, would be 60 (i.e., 40 × 1.5 = 60).

Remember that on Section I, our maximum was 75 points. Combined with the maximum total of 60 for Section II, we get a combined maximum of 135 points. ETS adds up the total composite scores for both sections and converts their sum into a simple, single-digit grade:

Seems terribly complicated, doesn’t it? Fortunately, you don’t need to memorize how ETS computes your score. You only need to know how to apply these conversions when determining your score on the practice test.

What’s a decent score? Naturally, you’d like to get a 3 or better. Some schools will accept a score of 3 or above as equivalent to a year of college biology. However, the top colleges only accept a 4 or 5. According to past exams, roughly two-thirds of the students who take the AP Biology Exam receive a grade of 3 or above. This means that in order to “pass” this test, you need to be somewhere in that top two-thirds. What do you need to do in order to get there?

Ms. C. Darwin takes an AP test

Suppose that a random student—we’ll call her C. Darwin—took the AP Biology Exam and left about half of Section I blank. That means she did 57 questions and left out 43 questions. Let’s say that out of the 57 she did, she missed 20. That gives Ms. Darwin 37 raw points.

This may not sound like a great performance. A score of 37 points out of 100 is not the kind of grade to report to colleges. Let’s see what happens here.

Her raw score for Section I would have been a 37. We multiply this raw score by 0.75 to get a composite score:

0.75 × 37 = 27.75

For Section II, let’s assume she answered all four essays and got 5 points for each question—once again, that’s only half the total potential! Altogether, that gives us a total of 20 points for Section II.

To obtain the composite score for Section II, we multiply the raw score by 1.5:

1.5 × 20 = 30

Taking the two composite scores, we can figure out Ms. Darwin’s total composite score:

We can round this up to a 58. Using the table on this page, you can see that a total composite score of 58 translates to a grade of 3 on the AP Biology Exam. Take a look back. Ms. Darwin got a 3, a passing grade, even though she blew off half of Section I and received only half credit on the essays! Not bad!

What All This Means for You

The bottom line is this: You should not be discouraged if you can’t answer every question on the test, even if you’re shooting for a score higher than a 3. This is particularly true of Section I, though we’ll soon see how the same thinking applies to Section II. It may be surprising to think of test taking in this way, but it really works. By the way, the conversions we’ve provided are based on ETS’s own calculations, the same ones they provide in their materials. Why don’t they let you know that you can skip half the test and still get a decent grade? Hmmm…

But what if you’re shooting for something higher than a 3? To reach that goal, you have to answer more questions. But even if you’re aiming for a 4 or a 5, you can leave some questions blank. Simply slow down so that you can do better on the questions with which you’re comfortable. Which ones are those? Obviously, the ones you know!

Let’s take a look at precisely how many questions you need to answer to get the score you desire:

But what if you don’t nail every question in your range? Don’t sweat it. We’ve already figured your mistakes into the pacing chart. We’ve assumed that, being human, you’ll miss a few questions on Section I and probably miss some of the essay points on Section II.

Use your time wisely. Go for the questions you know and skip the ones you don’t.

Even if you are aiming for a 5, you can leave a few questions blank. Remember that the 5 range, the highest score on the exam, starts at a composite of about 82. This is only 60 percent of the total possible score of 135. Hardly what you’d think of as a “perfect” grade.

For us, this means that there’s no reason to get bogged down with extremely difficult problems. If you come across a question that completely stumps you, skip it! You don’t need it anyway, not even to get a perfect score. Furthermore, if you spend lots of time on very tough problems, you’re less likely to have time for the problems you do know and consequently less likely to get the score you desire.

Taking an Actual Test

If you have not already taken a practice test, take one now. It will give you a much clearer idea of where you are in terms of pacing. It’s a good idea to take your first practice test the “regular” way, that is, without the pacing chart. This will give you an idea of what it’s like to try to do 100 multiple-choice questions and four essays in only three hours. After you’ve completed our book, go back and take a second practice test, applying the new techniques and biology review you’ve gained from this book.

We’ve provided you with two practice tests in the back of the book. We also recommend that you purchase an AP Biology Exam from ETS. You can purchase it at The College Board’s website: www.apcentral.collegeboard.com. You can do these tests in any order you like. If you do not have an ETS test, you might want to start with ours and do the ETS test once you’ve acquired it.

After you’ve scored your first test using the guidelines spelled out above, you’ll know how many questions you’ll need to answer to reach your goal. Pace yourself wisely, and you’re already on the path to higher scores.


According to the pacing chart, even those who want a perfect score do not have to answer all the questions on the test. The rest of us have even more leeway: We can leave up to half the test blank and get a 3. But which questions should we skip? The answer is pretty simple:

Skip the most difficult questions.

The AP Biology Exam covers a broad range of topics. There’s no way, even with our extensive review, that you will know everything about every topic in biology. So what should you do?

Do the Easiest Questions First

The best way to rack up points is to focus on the easiest questions first. Many of the questions asked on the test will be straightforward and require little effort. If you know the answer, nail it and move on. Others, however, will not be presented in such a clear, simple way. As you read each question, decide if it’s easy, medium, or hard. During a first pass, do all the easy questions. If you come across a problem that seems time‑consuming or completely incomprehensible, skip it. Remember:

Easier questions count just as much as harder ones, so your time is better spent on shorter, easier questions.

Save the medium questions for the second pass. These questions are either time‑consuming or require that you analyze all the answer choices (i.e., the correct answer doesn’t pop off the page). If you come across a question that makes no sense from the outset, save it for the last pass. You’re far more likely to fall into a trap or settle on a silly answer.

Watch Out for Those Bubbles!

Since you’re skipping problems, you need to keep careful track of the bubbles on your answer sheet. One way to accomplish this is by answering all the questions on a page and then transferring your choices to the answer sheet. If you prefer to enter them one by one, make sure you double-check the number beside the ovals before filling them in. We’d hate to see you lose points because you forgot to skip a bubble!

So then, what about the questions you don’t skip?


On most tests, you need to know your material backward and forward to get the right answer. In other words, if you don’t know the answer beforehand, you probably won’t answer the question correctly. This is particularly true of fill-in-the-blank and essay questions. We’re taught to think that the only way to get a question right is by knowing the answer. However, that’s not the case on Section I of the AP Biology Exam. You can get a perfect score on this portion of the test without knowing a single right answer … provided you know all the wrong answers!

What are we talking about? This is perhaps the single most important technique in terms of the Multiple-Choice section of the exam. Let’s take a look at an example on the next page.

1. The structures that act as the sites of gas exchange in a woody stem are the

(A) lungs

(B) gills

(C) lenticels

(D) ganglia

(E) lentil beans

Now if this were a fill-in-the-blank-style question, you might be in a heap of trouble. But let’s take a look at what we’ve got. You see “woody stem” in the question, which leads you to conclude that we’re talking about plants. Right away, you know the answer is not (A), (B), or (D) because plants don’t have lungs, gills, or ganglia. Now we’ve got it down to (C) and (E). Notice that (C) and (E) are very similar. Obviously, one of them is a trap. At this point, if you don’t know what “lentil beans” are, you have to guess. However, even if we don’t know precisely what they are, it’s safe to say that most of us know that lentil beans have nothing to do with plant respiration. Therefore, the correct answer is (C), lenticels.

Although our example is a little goofy and doesn’t look exactly like the questions you’ll be seeing on the test, it illustrates an important point:

Process of Elimination is the best way to approach the multiple-choice questions.

This is true of all three portions of Section I. Even when you don’t know the answer right off the bat, you’ll surely know that two or three of the answer choices are not correct. What then?


ETS tells you that random guessing will not affect your score. This is true. In other words, if you guess on five problems, odds are you’ll get one right. For the correct answer you’ll receive one point, while for the four wrong answers, you’ll lose one point (4 × [–1/4 point for each wrong answer] = –1 point). Net gain? Nothing!

However, the moment you’ve eliminated a couple of answer choices, your odds of getting the question right, even if you guess, are far greater. If you can eliminate as many as two answer choices, your odds improve enough that it’s in your best interest to guess. How so? Let’s look at an example.

Imagine that you’ve got three problems. On each problem, you’ve managed to eliminate two answer choices. If you guess on these three problems, you’re bound to get one right, statistically speaking. For the correct answer you receive one point, while for the two wrong answers, you lose one-half a point (2 × [–1/4 point for each wrong answer] = –1/2 point). Net gain? One-half a point.

This may not seem like much, but if you do it aggressively throughout the Multiple‑Choice section of the test, it could add as many as 10 to 15 points to your overall score. The difference between a decent test taker and an ace test taker is just this kind of aggressive approach.


Another way to rack up the points on the AP Biology Exam is by using word associations in tandem with your POE skills. Make sure that you memorize the words in the Key Words lists throughout this book. Know them backward and forward. As you learn them, make sure you group them by association, since ETS is bound to ask about them on the AP Biology Exam. What do we mean by “word associations”? Let’s take the example of mitosis and meiosis.

You’ll soon see from our review that there are several terms associated with mitosis and meiosis. Synapsis, crossing-over, and tetrads, for example, are words associated with meiosis but not mitosis. We’ll explain what these words mean in Chapter 7, in which we discuss reproduction. For now, just take a look:

2. Which of the following typifies cytokinesis during mitosis?

(A) Crossing-over

(B) Formation of the spindle

(C) Formation of tetrads

(D) Synapsis

(E) Division of the cytoplasm

This might seem like a difficult problem. But let’s think about the associations we just discussed. The question asks us about mitosis. However, answer choices (A), (C), and (D) all mention events that we’ve associated with meiosis. Therefore, they are out. Without even racking your brain, you’ve managed to get this down to two answer choices. Not bad! For the record, the correct answer would then be (E), division of the cytoplasm.

Once again, don’t worry about the science for now. We’ll review it later. What is important to recognize is that by combining the associations we’ll offer throughout this book and your aggressive POE techniques, you’ll be able to rack up points on problems that might have seemed difficult at first.


One of the big keys to simplifying biology is the organization of terms into a handful of easily remembered packages. The best way to accomplish this is by using mnemonics. Biology is all about names: the names of chemical structures, processes, theories, etc. How are you going to keep them all straight? A mnemonic, as you may already know, is a convenient device for remembering something.

For example, one important issue in biology is taxonomy, that is, the classification of life forms, or organisms. Organisms are classified in a descending system of similarity, leading from kingdoms (the broadest level) to species (the most specific level). The complete order runs: domain, kingdom, phylum, class, order, family, genus, and species. Don’t freak out yet. Look how easy it becomes with a mnemonic:

King Philip of Germany decided to walk to America. What do you think happened?

















Learn the mnemonic and you’ll never forget the science!

Mnemonics can be as goofy as you like, so long as they help you remember. Throughout this book, we’ll give you mnemonics for many of the complicated terms we’ll be seeing. Use ours, if you like them, or feel free to invent your own. Be creative! Remember: The important thing is that you remember the information, not how you remember it.


About 10 percent of the multiple-choice questions in Section I are EXCEPT/NOT/LEAST questions. With this type of question, you must remember that you’re looking for the wrong (or the least correct) answer. The best way to go about these is by using POE.

More often than not, the correct answer is a true statement, but is wrong in the context of the question. However, the other four tend to be pretty straightforward. Cross off the four that apply and you’re left with the one that does not. Here’s a sample question:

17. All of the following are true statements about gametes EXCEPT:

(A) They are haploid cells.

(B) They are produced only in the reproductive structures.

(C) They bring about genetic variation among offspring.

(D) They develop from polar bodies.

(E) They combine to produce cells with the diploid number of chromosomes.

If you don’t remember anything about gametes and gametogenesis, or the production of gametes, this might be a particularly difficult problem. We’ll see these again later on, but for now, remember that gametes are the “sex cells” of sexually reproducing organisms. As such, we know that they are haploid and are produced in the sexual organs. We also know that they come together to create offspring.

From this very basic review, we know immediately that (A), (B), and (E) are not our answers. All three of these are accurate statements, so we eliminate them. That leaves us with (C) and (D). If you have no idea what (D) means, focus on (C). In sexual reproduction, each parent contributes one gamete, or half the genetic complement of the offspring. This definitely helps vary the genetic makeup of the offspring. Answer choice (C) is a true statement, so it can be eliminated. The correct answer is (D).

Don’t sweat it if you don’t recall the biology. We’ll be reviewing it in detail soon enough. For now, remember that the best way to answer these types of questions is: Spot all the right statements and cross them off. You’ll wind up with the wrong statement, which happens to be the correct answer.


You are given four essay questions to answer in 90 minutes. As we said already, that’s only 22 minutes per question! The best way to rack up points on this section is to give the essay readers what they’re looking for. Fortunately, we know precisely what that is.

The ETS essay reviewers have a checklist of key terms and concepts that they use to assign points. We like to call these “hot button” terms. Quite simply put, for each hot button that you include in your essay, you will receive a predetermined number of points. For example, if the essay question deals with the function of enzymes, the ETS graders are instructed to give 2 points for a mention of the “lock-and-key theory of enzyme specificity.”

Naturally, you can’t just compose a “laundry list” of scientific terms. Otherwise, it wouldn’t be an essay. What you can do, however, is organize your essay around a handful of these key, or hot button, points. The most effective and efficient way to do this is by using the 10-minute reading period to brainstorm and come up with the scientific terms. Then outline your essay before you begin to write, using your hot buttons as your guide.

Recurring Themes

In the AP Biology Exam, you will need to make connections between eight recurring themes and concepts covered in your AP biology course. The major themes are:

1. Science as a Process

2. Evolution

3. Energy Transfer

4. Continuity and Change

5. Relationship of Structure to Function

6. Regulation

7. Interdependence in Nature

8. Science, Technology, and Society

These themes are particularly helpful to remember for the essay portion of the test. One of the favorite themes (that is often an essay question on the AP test) is the relationship between structure and function. Several topics are perfectly suited to this theme, such as the structure of mitochondria, neurons, chloroplasts, or bones of birds. In each case, you have to explain in detail how the structure of the item relates to its function. For example, the structure of a mitochondrion (its outer membrane, the folding of the inner membrane, and the intermembrane space) relates to the process of cellular respiration. The eight themes above will give you a framework for understanding biology and help you connect topics together and write a great essay.

Brainstorm and Outline

During the 10-minute preview, read each question twice and brainstorm the terms and concepts you want to cover with regard to each question. Once you’ve jotted down as many as you can, draft an outline that will help you organize them into some logical order.

Although the ETS graders do not grade you on your overall organization, a poorly organized essay tends to be less convincing than a well-organized one. The best way to avoid any problems with organization is to draw up a clear, simple outline. This can be done during the 10-minute reading period.

On average, you need to write one or two paragraphs for each part of the question. If the question asks for two examples, give just that—two examples. If you present more than two examples, the reviewers may not even count them toward your score. Make sure you read carefully and give them what they want!

Label Diagrams and Figures

Sometimes it’s easier to present a diagram or figure as part of your essay. If you choose to do this, make sure you label your diagram or figure properly and reference it in your essay. Otherwise, the ETS graders will give you no more than partial credit for your work.

Review Laboratory Experiments Covered in Your AP Course

At least one of the four questions will be experimentally based. Sometimes questions will refer back to a laboratory experiment conducted in your AP class. Consequently, the laboratory component of your course is an integral part of this exam. Don’t forget that. In Chapter 15, we’ll review some of the laboratory experiments (including equipment) that you’re responsible for on the AP test.

Sample Essays

Chapter 14 goes into far greater detail about the free-response questions. Take a look at it after you’ve reviewed the biology in the first part of this book.

There are sample essays as well as a checklist just like the one the ETS essay graders use when correcting your essay. Use them as guidelines when writing your own free‑response essays for the practice test.

Correcting the essays isn’t as clear-cut as correcting the multiple-choice questions. Nevertheless, by following our instructions, you’ll be able to give yourself a rough idea of how you perform on this portion of the test.


Along the way, we’ll highlight what’s important in each area, from cell structure to genetics to evolution. By helping you at each step, we take all the guesswork out of preparing for the test. In addition, as you’ll soon see, we don’t need to be dull and long‑faced when it comes to biology. We can have some fun learning. Given the many advances that are being made in genetics, cell biology, and immunology, all this stuff is actually very interesting if it’s looked at the right way. You may not believe it now, but by the end of this book, we’re certain that you’ll agree. (Especially when you see your test scores!)

We’ve done our work: We’ve taken the AP Biology Exam apart, pulled out the pieces you need to know, and presented them in an easy, accessible format. Now it’s time for you to do your share. Follow along closely and answer all the questions at the end of each chapter. Answers to the quizzes and explanations for all the questions are found in Chapter 16 in the back of the book. If you learn the material on these pages, you’re sure to improve your score.

Before we get started, let’s look at a quick summary of the strategies you need to remember for the test:

  • Pacing: Know your pacing chart! Spend more time answering fewer questions.
  • The Three-Pass System: Focus your energy on the easy questions first—save the rest for later.
  • Process of Elimination: Use POE to answer questions. Remember you don’t need to know the right answers to get the questions right.
  • Aggressive Guessing: Guess after you’ve eliminated two or more answer choices—it’s in your best interest.
  • Word Associations: Learn the lists at the end of each chapter. Know which words should be grouped together.
  • Mnemonics: Use ours or make your own.
  • Identifying Question Types: Look out for EXCEPT questions.
  • The Art of the ETS Essay: Brainstorm, outline, write—and make sure you brush up on those “hot button” terms and recurring themes.

If you’re comfortable with these strategies come test day, your score is bound to improve. Before we get there, however, we need to review the biology you’ll see on the test. Without any further ado, let’s get moving!