The two long free-response questions on the AP Biology exam carry just over half of the FRQ section's raw points (18 of 34 in 2025), which is roughly a quarter of the total score. They're where the biggest single-question point swings happen. Get both long FRQs into full marks and you can absorb a mediocre performance on the multiple choice; miss half the points on both and it's very hard to recover a 5.
This guide focuses on the long FRQs specifically. They're 8 to 10 points each (9 each in 2025), with about 25 minutes suggested for each, and both are built around interpreting and evaluating experimental results, with the second also requiring a graph. The rubric moves are distinct, and students who reliably score full marks share a small set of habits worth breaking down.
What the long FRQs really are
Section II has six FRQs in 90 minutes. Two long (Questions 1 and 2), worth 8 to 10 points each. Four short, worth 4 points each.
The two long FRQs follow a fixed pattern. Question 1 is Interpreting and Evaluating Experimental Results; Question 2 is Interpreting and Evaluating Experimental Results with Graphing, which includes points for constructing a graph from data. Both are set in a biological system (signal transduction, cellular respiration, natural selection, an ecological interaction) and ask you to explain the mechanism and predict outcomes when a variable changes.
Both types share a rubric structure: multiple sub-parts, each awarding one or two points, each scored against specific accepted responses. The rubric is additive; there's no penalty for wrong extras as long as they don't contradict your correct answer.
The long FRQ rubric decoded
Each sub-part is scored against a specific list of accepted responses. Get the task verb right, hit the required concept in the right level of detail, and you earn the point. The rubric doesn't reward general biological knowledge; it rewards specific concepts matched to specific task words.
| Task verb | What the point requires |
|---|---|
| Identify / State | A single correct answer, no explanation needed. |
| Describe | What happens, in the right order, without reasoning. |
| Explain | What happens AND why (the mechanism). Missing the mechanism when the prompt says explain is one of the most common ways to lose a point. |
| Predict | A specific outcome based on the scenario in the prompt. |
| Justify | Your prediction PLUS the biological reasoning that supports it. |
| Calculate | The correct number, with units where the question asks for them. Show your setup so you can check your work; calculation points are usually awarded for the correct answer, so don't count on partial credit. |
| Construct a graph | The right graph type for the data, accurately plotted points (and error bars if data are given), and labeled axes with units. In 2025 these were three separate points. |
| Design an experiment | Independent variable, dependent variable, controls, replicates or sample size, and predicted results. Missing any of these usually costs a point. |
Step 1: Read the whole question first
Every long FRQ is a connected scenario. You can't answer part c well without knowing what's in the stem and part a. Before writing, read the entire question including all sub-parts, and skim any accompanying data.
Underline every task verb. Circle the specific biology being asked about. Note any numbers you'll need.
Then sketch a one-line answer plan next to each sub-part. Not full sentences, just the key concept. This takes ninety seconds and prevents the most common cause of lost points: running out of time on the last sub-part, or missing that sub-part d builds on your answer to sub-part b.
Step 2: For experimental design questions, hit all five criteria
Experimental design is the most rubric-mechanical of the long FRQ types. A full-marks response to "design an experiment to test whether X affects Y" almost always needs to name five things: the independent variable (what you're changing), the dependent variable (what you're measuring), the controls (what stays the same and any control group), the sample size or number of replicates, and the predicted results.
Students lose points here by skipping the boring parts. Naming the independent and dependent variables is easy; describing your controls (a control group treated identically except for the independent variable, temperature held constant, same age of organism) is what separates 3-point responses from 4-point ones. Same for replicates: "repeat the experiment with at least ten plants per condition" earns the point where "repeat the experiment" doesn't.
The predicted results line does two things at once: it forces you to think about what the data would look like if your hypothesis is correct, and it demonstrates that you understand what the experiment is testing. "If X causes an increase in Y, we expect to see higher Y values in the treated group than the control group" is a full-credit predicted-results sentence.
Design-an-experiment questions reward specificity. "Grow bacteria in a nutrient medium" is vague. "Grow E. coli in LB broth at 37 degrees C" is specific. Named organisms, named media, and specific temperatures or timings make it clear you've controlled the right variables.
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Step 3: Explain the mechanism behind the data
Both long FRQs are set inside a biological system: a signaling pathway, a metabolic pathway, a homeostatic loop, or an evolutionary scenario. These questions test whether you can explain how a process works and predict what happens when you change a variable.
The rubric scans for specific mechanism vocabulary. Writing "the cell membrane responds" earns nothing when the accepted response is "the receptor tyrosine kinase autophosphorylates, initiating the intracellular signaling cascade." You don't need to hit exactly the rubric's words, but you need to name the specific molecule, structure, or process the mechanism runs on.
When the question asks you to predict what happens if a variable changes (a receptor is blocked, a substrate is removed, an enzyme is mutated), your answer should trace the mechanism forward: "If receptor X is blocked, the downstream cascade won't be initiated, so the target gene won't be transcribed, so the cell won't proliferate." Each step is potentially worth a point.
Draw diagrams if they help you think, but the rubric points come from the labeled biology, not from the drawing quality. A labeled arrow with the correct molecule name earns the point; a beautiful drawing without labels doesn't.
Step 4: Timing across the two long questions
College Board's exam instructions suggest about 25 minutes on each long question and about 10 minutes on each short one, which uses the full 90 minutes. If you want a few minutes at the end to check work, trim a couple of minutes from each long question.
Inside a long question, budget your time by sub-part weight, not by sub-part count. If sub-parts a and b are worth one point each and sub-parts c and d are worth two points each, spend less time on a and b even if they look harder. The rubric doesn't reward heroic answers to low-weight sub-parts; it rewards clearing the ones with more points on offer.
If you're stuck on a sub-part, skip it and come back. Every sub-part is scored independently, so getting stuck on b doesn't stop you earning marks on c and d. What costs the most points is spending fifteen minutes on one sub-part while the rest of the paper stays blank.
If time is running out on the last sub-part of a long question, write your answer as labeled bullet points instead of prose. The rubric scans for concepts; a bullet naming the correct mechanism earns the point even if you didn't have time to write the full explanation.
Common mistakes that cost points
Answering the wrong task verb. Explaining when the question asks you to describe adds material that doesn't score. Describing when the question asks you to explain misses the mechanism point.
Being too vague. "The cell membrane is affected" scores zero when the accepted response is "the phospholipid bilayer becomes more fluid." Named organelles, named molecules, named processes are what the rubric scans for.
Skipping the controls on a design question. The controls line is where design responses go from 2 points to 3 or 4. It's the easiest point to leave on the table.
Not showing setup on calculations. Writing out the equation with numbers substituted helps you catch arithmetic slips before they cost you the point, and makes your reasoning clear where a question asks you to support your answer.
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