AP Biology FRQ Tips

How to turn what you know into points on the free-response questions.

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Free-response questions reward specific, complete answers that use the information given. Each point is earned separately, so a short answer to every part beats a long answer to one part. Write in complete sentences unless the question asks for a graph, a label or a calculation.

The ATP rule: Answer The Prompt. Do exactly what the bolded task verb asks. If it says identify, name it. If it says explain, give the how or why. Extra information does not earn extra points.

1. Read the command word first

The verb tells you how much to write. Answering a different verb is the most common way to lose a point.

Command word	What to write
Identify / State	Name it. No explanation needed.
Describe	Give the characteristics, parts or pattern: what you see or what happens.
Explain	Give the how or why. Connect a cause to an effect with a biological reason.
Justify / Support a claim	Make a claim, then back it with evidence (data or a fact) and the biological reasoning that links them.
Predict	Say what will happen, then give the reason. A prediction with no reason usually earns nothing.
Calculate	Show the setup, the numbers and the answer with units.
Construct a graph	Draw the graph yourself (see section 3).
Compare	Say how they are alike and/or different, using words like “whereas” or “both.”

2. Use the data: claim, evidence, reasoning

Claim: a one-sentence answer to the question.
Evidence: quote actual numbers or trends from the table or graph (“at 40 °C the rate was 12 units, compared with 5 units at 20 °C”).
Reasoning: the biology that explains why the evidence supports the claim (“higher temperature increases collisions between enzyme and substrate”).

Compare, don’t just name. “Rate is higher” is vague. “Rate is higher in the treatment than in the control” names what is being compared.

3. Graphing checklist

On a question that asks you to construct a graph, you are usually graded on several separate points. Check each one:

Axes are labeled with the variable and its units. The independent variable (what was changed) is on the x-axis and the dependent variable (what was measured) is on the y-axis.
The scale is even and uses most of the grid. A broken or uneven scale loses the point.
The graph type fits the data. Use a line graph for continuous data such as time or temperature. Use a bar graph for categories. The question may or may not tell you which to use, so decide from the data.
All points or bars are plotted accurately. Connect line-graph points with a line.
If error bars are given (for example, standard error of the mean), draw them at each point or bar using the values from the table.
Several data sets on one graph are distinguished with a key or labels.
You do not need a graph title. Graph titles are not scored, so spend that time on the axes and the points.

Interpreting error bars: if the error bars of two groups overlap a lot, the difference may not be meaningful. If they do not overlap, the difference is more likely to be real. Say this in the words the question uses (for example, “the difference is probably not statistically significant”), and do not claim certainty.

4. Calculation checklist

Write the formula (the formula sheet is in your exam booklet) and substitute the numbers.
Show your work. A wrong final answer can still earn points for a correct setup.
Include units and round the way the question tells you (for example, to the nearest tenth).
Reasonableness check: does the size and sign of the answer make sense? Water potential, for example, is often negative.

5. Designing or evaluating an experiment

Name these every time

Independent variable: the one thing you change.
Dependent variable: what you measure.
Controlled variables (constants): what you keep the same.
Control group: a comparison with no treatment, or the normal condition.
Replicates or a large sample: repeating trials makes the result more reliable.

Common follow-up questions

Why include a negative control? It shows the result is caused by the treatment and not by something else.
Identify a flaw: too few trials, more than one variable changed, or no control group.
Null hypothesis: there is no difference or effect.

6. Point-losing mistakes to avoid

Restating the question. Repeating it earns no point. Add new information.
Vague words: “it affects,” “it changes,” “it helps.” Say what changes and in which direction (increases or decreases).
Giving cells or molecules goals: “the cell wants” or “the enzyme tries.” Describe the mechanism instead.
Mixing up terms: transcription and translation, diffusion and osmosis, mitosis and meiosis. Define the term in your own words if you are unsure.
Correlation as cause. Data from one experiment support a claim. They do not prove it.
Contradicting yourself. If you cross out an answer, cross it out completely. Do not leave two different answers for one part.
Leaving a part blank. A reasonable attempt can earn credit. A blank cannot.

7. Pacing

Plan on about 2.5 minutes for each bolded task verb in a free-response question. A graph counts as about three task verbs, so give it roughly 7.5 minutes.
Spend a minute marking command words and underlining what each part asks for.
Answer in the space provided and label parts clearly: (a), (b), (c).
Short questions need only a sentence or two for each point. Do not write a paragraph for one point.
If you are stuck on one part, move on. Parts are usually scored separately.

Practice. Try the free-response questions in each unit’s Question Bank, or build a practice paper. Then score yourself part by part against this checklist.

These tips are general study advice for AP Biology free-response questions. Check the current AP Biology Course and Exam Description and the official scoring guidelines on AP Central for exact requirements.