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AP Biology Free Response Questions (FRQ) – Past Prompts

34 min read • december 29, 2020

Dylan Black

We’ve compiled a list of a bunch of the AP Biology past prompts! The AP Bio FRQs are 60% of the exam including 2 long questions and 4 short questions. It’s important that you understand the rubrics and question styles going into the exam. Use this list to practice!

By practicing with previously released free-response questions (FRQs), you’ll build critical-thinking and analytical skills that will prepare you for the exam. These past prompts have been designed to help you connect concepts and ideas to each other while applying your knowledge to real-life scenarios. You’ll also learn how to tackle the exam in a better format, and you won’t be surprised come test day with certain questions.

All recredit to College Board.

👉 AP Bio 2019 FRQs

Long FRQ #1

Gene expression and regulation, ecology (gene expression and symbiosis).

Auxins are plant hormones that coordinate several aspects of root growth and development. Indole-3-acetic acid (IAA) is an auxin that is usually synthesized from the amino acid tryptophan (Figure 1). Gene Trp-T encodes an enzyme that converts tryptophan to indole-3-pyruvic acid (I3PA), which is then converted to IAA by an enzyme encoded by the gene YUC .

Circle ONE arrow that represents transcription on the template pathway. Identify the molecule that would be absent if enzyme YUC is nonfunctional.

Predict how the deletion of one base pair in the fourth codon of the coding region of gene Trp-T would most likely affect the production of IAA. Justify your prediction.

Explain one feedback mechanism by which a cell could prevent production of too much IAA without limiting I3PA production

Rhizobacteria are a group of bacteria that live in nodules on plant roots. Rhizobacteria can produce IAA and convert atmospheric nitrogen into forms that can be used by plants. Plants release carbon-containing molecules into the nodules. Based on this information, identify the most likely ecological relationship between plants and rhizobacteria. Describe ONE advantage to the bacteria of producing IAA.

A researcher removed a plant nodule and identified several “cheater” rhizobacteria that do not produce IAA or fix nitrogen. Describe the evolutionary advantage of being a bacterial cheater in a population composed predominantly of noncheater bacteria. Plants can adjust the amount of carbon-containing molecules released into nodules in response to the amount of nitrogen fixed in the nodule. Predict the change in the bacterial population that would cause the plant to reduce the amount of carbon-containing molecules provided to the nodule.

Long FRQ #2

Units 2 and 8 (competition and osmoregulation).

A student studying two different aquatic, plant-eating, unicellular protist species (species A and B) designed an experiment to investigate the ecological relationship between the two species (Table 1).

In treatment group I, the student placed 10 individuals of species A into a container with liquid growth medium and 10 individuals of species B into a separate container with an equal amount of the same liquid growth medium. In treatment group II, the student placed 5 individuals of each species into a single container with the liquid growth medium. The student then maintained the containers under the same environmental conditions and recorded the number of individuals in each population at various time points. The results are shown in Table 2.

The growth curves for species B in group I and for species A in group II (shaded columns) have been plotted on the template. Use the template to complete an appropriately labeled line graph to illustrate the growth of species A in treatment group I and species B in treatment group II (unshaded columns).

As shown in the table, the student established treatment group II with 5 individuals of each species. Provide reasoning for the reduced initial population sizes.

The student claims that species A and B compete for the same food source. Provide TWO pieces of evidence from the data that support the student’s claim.

Predict TWO factors that will most likely limit the population growth of species A in treatment group I.

Many protists contain an organelle called a contractile vacuole that pumps water out of the cell. The student repeated the experiment using a growth medium with a lower solute concentration. Predict how the activity of the contractile vacuole will change under the new experimental conditions. Justify your prediction.

Short FRQ #1

Cellular energetics, heredity (cellular respiration and sex linked inheritance).

The pyruvate dehydrogenase complex (PDC) catalyzes the conversion of pyruvate to acetyl-CoA, a substrate for the Krebs (citric acid) cycle. The rate of pyruvate conversion is greatly reduced in individuals with PDC deficiency, a rare disorder.

Identify the cellular location where PDC is most active.

Make a claim about how PDC deficiency affects the amount of NADH produced by glycolysis AND the amount of NADH produced by the Krebs (citric acid) cycle in a cell. Provide reasoning to support your claims based on the position of the PDC-catalyzed reaction in the sequence of the cellular respiration pathway.

PDC deficiency is caused by mutations in the PDHA1 gene, which is located on the X chromosome. A male with PDC deficiency and a homozygous female with no family history of PDC deficiency have a male offspring. Calculate the probability that the male offspring will have PDC deficiency.

Short FRQ #2

Cell communication and cell cycle (cell signaling).

Acetylcholine is a neurotransmitter that can activate an action potential in a postsynaptic neuron (Figures 1 and 2). A researcher is investigating the effect of a particular neurotoxin that causes the amount of acetylcholine released from presynaptic neurons to increase.

Describe the immediate effect of the neurotoxin on the number of action potentials in a postsynaptic neuron. Predict whether the maximum membrane potential of the postsynaptic neuron will increase, decrease, or stay the same.

The researcher proposes two models, A and B, for using acetylcholinesterase (AChE), an enzyme that degrades acetylcholine, to prevent the effect of the neurotoxin. In model A, AChE is added to the synapse. In model B, AChE is added to the cytoplasm of the postsynaptic cell. Predict the effectiveness of EACH proposed model. Provide reasoning to support your predictions.

Short FRQ #3

Natural selection (cladograms and evolutionary relationships).

A researcher studying the evolutionary relationship among five primate species obtained data from a sequence of mitochondrial DNA (mtDNA) from a representative individual of each species. The researcher then calculated the percent divergence in the sequences between each pair of primate species (Table 1).

Based on fossil data, the researcher estimates that humans and their most closely related species in the data set diverged approximately seven million years ago. Using these data, calculate the rate of mtDNA percent divergence per million years between humans and their most closely related species in the data set. Round your answer to two decimal places.

Using the data in the table, construct a cladogram on the template provided. Provide reasoning for the placement of gibbons as the outgroup on the cladogram.

On the cladogram, draw a circle around all of the species that are descended from the species indicated by the node within the square.

Short FRQ #4

Cell communication and cell cycle (gene expression).

The yeast Saccharomyces cerevisiae is a single-celled organism. Amino acid synthesis in yeast cells occurs through metabolic pathways, and enzymes in the synthesis pathways are encoded by different genes. The synthesis of a particular amino acid can be prevented by mutation of a gene encoding an enzyme in the required pathway. A researcher conducted an experiment to determine the ability of yeast to grow on media that differ in amino acid content. Yeast can grow as both haploid and diploid cells. The researcher tested two different haploid yeast strains (Mutant 1 and Mutant 2), each of which has a single recessive mutation, and a haploid wild-type strain. The resulting data are shown in Table 1.

Identify the role of treatment I in the experiment.

Provide reasoning to explain how Mutant 1 can grow on treatment I medium but cannot grow on treatment III medium.

Yeast mate by fusing two haploid cells to make a diploid cell. In a second experiment, the researcher mates the Mutant 1 and Mutant 2 haploid strains to produce diploid cells. Using the table provided, predict whether the diploid cells will grow on each of the four media. Use a plus sign (+) to indicate growth and a minus sign (−) to indicate no growth.

Short FRQ #5

A researcher is studying patterns of gene expression in mice. The researcher collected samples from six different tissues in a healthy mouse and measured the amount of mRNA from six genes. The data are shown in Figure 1.

Based on the data provided, identify the gene that is most likely to encode a protein that is an essential component of glycolysis. Provide reasoning to support your identification.

The researcher observed that tissues with a high level of gene H mRNA did not always have gene H protein. Provide reasoning to explain how tissues with high gene H mRNA levels can have no gene H protein.

Short FRQ #6

Cell structure and function (cellular transport).

The petal color of the Mexican morning glory (Ipomoea tricolor ) changes from red to blue, and the petal cells swell during flower opening. The pigment heavenly blue anthocyanin is found in the vacuole of petal cells. Petal color is determined by the pH of the vacuole. A model of a morning glory petal cell before and after flower opening is shown in Table 1.

Identify the cellular component in the model that is responsible for the increase in the pH of the vacuole during flower opening AND describe the component’s role in changing the pH of the vacuole.

A researcher claims that the activation of the K+/H+ transport protein causes the vacuole to swell with water. Provide reasoning to support the researcher’s claim.

👉 AP Bio 2018 FRQs

Polar bears are highly adapted for life in cold climates around the North Pole. Brown bears, black bears, and pandas are found in warmer environments. Researchers collected complete mitochondrial DNA sequences from several populations of bears and constructed a phylogenetic tree to represent their evolutionary relatedness (Figure 1). A researcher studying adaptation in bears sequenced the nuclear gene encoding a lysosomal trafficking protein (LYST) in polar bears, brown bears, black bears, and panda bears. There are seven inferred amino acid substitutions that are found only in polar bears. Mutations that cause similar substitutions in the human LYST protein are associated with Chediak-Higashi syndrome, an autosomal recessive condition in which pigment is absent from the hair and eyes. The researcher used the inferred amino acid sequences to build the distance matrix shown in Table 1.

Use the phylogenetic tree in Figure 1 to estimate the age in hundreds of thousands of years of the most recent common ancestor of all brown bears. Identify the population of brown bears to which polar bears are most closely related based on the mitochondrial DNA sequence comparison. Identify two populations whose positions could be switched without affecting the relationships illustrated in the phylogenetic tree.

Construct a cladogram on the template to represent a model of the evolutionary relatedness among the bear species based on the differences in LYST protein sequences (Table 1). Circle the position on the cladogram that represents the out-group.

A student claims that mitochondrial DNA sequence comparisons provide a more accurate phylogeny of bear species than do LYST protein sequence comparisons. Provide ONE piece of reasoning to support the student’s claim.

A researcher genetically engineers a mouse strain by deleting the mouse lyst gene and replacing it with the polar bear lyst gene. Predict the most likely difference in phenotype of the transgenic mouse strain compared to the wild-type mouse strain. Justify your prediction.

Describe how the mutation in the lyst gene became common in the polar bear population. If the lyst gene were the only determinant of fur color, predict the percent of white offspring produced by a mating between a polar bear and a brown bear.

Cell Communication and Cell Cycle (Gene Regulation)

Some pathogenic bacteria enter cells, replicate, and spread to other cells, causing illness in the host organism. Host cells respond to these infections in a number of ways, one of which involves activating particular enzymatic pathways (Figure 1). Cells normally produce a steady supply of inactive caspase-1 protein. In response to intracellular pathogens, the inactive caspase-1 is cleaved and forms an active caspase-1 (step 1). Active caspase-1 can cleave two other proteins. When caspase-1 cleaves an inactive interleukin (step 2), the active portion of the interleukin is released from the cell. An interleukin is a signaling molecule that can activate the immune response. When caspase-1 cleaves gasdermin (step 3), the N-terminal portions of several gasdermin proteins associate in the cell membrane to form large, nonspecific pores. Researchers created the model in Figure 1 using data from cell fractionation studies. In the experiments, various parts of the cell were separated into fractions by mechanical and chemical methods. Specific proteins known to be located in different parts of the cell were used as markers to determine the location of other proteins. The table below shows the presence of known proteins in specific cellular fractions.

Describe the effect of inhibiting step 3 on the formation of pores AND on the release of interleukin from the cell.

Make a claim about how cleaving inactive caspase-1 results in activation of caspase-1. A student claims that preinfection production of inactive precursors shortens the response time of a cell to a bacterial infection. Provide ONE reason to support the student’s claim.

A student claims that the NF-kB protein is located in the cytoplasm until the protein is needed for transcription. Justify the student’s claim with evidence. Identify TWO fractions where N-terminal gasdermin would be found in cells infected with pathogenic bacteria.

Describe the most likely effect of gasdermin pore formation on water balance in the cell in a hypotonic environment.

Explain how gasdermin pore formation AND interleukin release contribute to an organism’s defense against a bacterial pathogen.

Seagrasses are aquatic plants that reproduce sexually. Male seagrass flowers produce sticky pollen that is carried by circulating water to female flowers, resulting in fertilization. A researcher claims that mobile aquatic invertebrates can also transfer pollen from male to female flowers in the absence of circulating water. To investigate this claim, the researcher set up aquariums to model the possible interactions between the invertebrates and seagrasses.

Use the symbols below and the template aquariums to demonstrate the experimental design for testing the researcher’s claim that mobile aquatic invertebrates can pollinate seagrass in the absence of circulating water. Draw the appropriate symbols in the negative control aquarium AND the experimental aquarium. Do not use any symbol more than once in the same aquarium.

Identify the dependent variable in the experiment. Predict the experimental results that would support the researcher’s claim that mobile aquatic invertebrates can also transfer pollen from male to female flowers in the absence of circulating water.

Cell Structure and Function (Cell Transport and Experimental Design)

The common bedbug ( Cimex lectularius ) is a species of insect that is becoming increasingly resistant to insecticides. Bedbugs possess several genes suspected of contributing to the resistance, including P450 , Abc8 , and Cps . To investigate the role of these genes in insecticide resistance, researchers deleted one or more of these genes in different strains of bedbugs, as indicated in Figure 1, and treated the strains with the insecticide beta-cyfluthrin. Each strain was genetically identical except for the deleted gene(s) and was equally fit in the absence of beta-cyfluthrin. The percent survival of each strain following beta-cyfluthrin treatment is shown in Figure 1.

Identify the control strain in the experiment. Use the means and confidence intervals in Figure 1 to justify the claim that Abc8 is effective at providing resistance to beta-cyfluthrin.

P450 encodes an enzyme that detoxifies insecticides. Abc8 encodes a transporter protein that pumps insecticides out of cells. Cps encodes an external structural protein located in the exoskeleton that greatly reduces the absorption of insecticides. Based on this information and the data in Figure 1, explain how a deletion of both P450 and Abc8 results in lower survival in bedbugs compared with a deletion of Cps only.

Ecology (Symbiotic Relationships)

Some birds, including great spotted cuckoos, lay their eggs in the nests of other birds, such as reed warblers. The warbler parents raise the unrelated chicks and provide them with food that would otherwise be given to their biological offspring. A researcher conducted an investigation to determine the type of relationship between warblers and cuckoos in an environment without predators. The researcher found that nests containing only warblers were more likely to be successful than nests containing warblers and cuckoos (data not shown). A successful nest is defined as a nest where at least one chick becomes an adult warbler. In some geographic areas, several species of nest predators are present. Researchers have found that cuckoo chicks, while in the nest, produce a smelly substance that deters nest predators. The substance does not remain in the nest if cuckoo chicks are removed. Figure 1 shows the probability that nests containing only warblers or containing both warblers and cuckoos will be successful in an environment with predators. In a follow-up experiment, the researchers added cuckoos to a nest that contained only warblers (group 1) and removed cuckoos from a nest containing warblers and cuckoos (group 2).

Describe the symbiotic relationship that exists between the cuckoo and warbler in an environment without predators.

On the template provided, draw bars in the appropriate locations to predict the relative probability of success for the nest in the presence of predators where:

the cuckoos were added to the nest containing only warblers (group 1)

the cuckoos were removed from the nest containing warblers and cuckoos (group 2)

Identify the symbiotic relationship that exists between the cuckoo and the warbler in the presence of predators.

Cystic fibrosis is a genetic condition that is associated with defects in the CFTR protein. The CFTR protein is a gated ion channel that requires ATP binding in order to allow chloride ions (Cl−) to diffuse across the membrane.

In the provided model of a cell, draw arrows to describe the pathway for production of a normal CFTR protein from gene expression to final cellular location.

Identify the most likely cellular location of the ribosomes that synthesize CFTR protein.

Identify the most likely cellular location of a mutant CFTR protein that has an amino acid substitution in the ATP-binding site.

Heredity (Sex Linked Heredity)

In the tongue sole fish (Cynoglossus semilaevis), sex is determined by a combination of genetics and environmental temperature. Genetically male fish have two Z chromosomes (ZZ), and genetically female fish have one Z chromosome and one W chromosome (ZW). When fish are raised at 22℃, ZZ fish develop into phenotypic males and ZW fish develop into phenotypic females. However, when fish are raised at 28℃, the Z chromosome is modified (denoted as Z*). Z*W individuals develop as phenotypic males that are fertile and can pass on the Z* chromosome to their offspring even when the offspring are raised at 22℃. A cross between a ZW female and a Z*Z male is shown in the Punnett square below.

Predict the percent of phenotypic males among the F1 offspring of the cross shown in the Punnett square if the offspring are raised at 22℃.

At least one Z or Z* chromosome is necessary for survival of the fish. A researcher crossed two fish and observed a 2:1 ratio of males to females among the offspring. Based on the information, identify the genotype of the male parent in the cross. Describe ONE fitness cost to the female of mating with this particular male.

Cell Communication and Cell Cycle

Acetylcholine receptor (AChR) proteins are found at the synapse between neurons and skeletal muscle cells. Acetylcholine released from neurons binds to a specific site on the receptor proteins, which causes an ion channel in the receptors to open and allow sodium ions (Na+) to enter muscle cells. The resulting depolarization of muscle cells initiates muscle contractions. Another molecule, nicotine, can also bind to certain types of AChR proteins and activate the receptors.A researcher is investigating two different types of AChR proteins: type 1 and type 2. To determine which stimuli activate the receptors, the researcher exposes muscle cells expressing the different types of receptor proteins to stimuli and observes the results indicated in Table 1.

Describe the difference in the structure AND function between AChR type 1 and AChR type 2.

Acetylcholinesterase is an enzyme that breaks down acetylcholine in the synapse. Describe the effect of inhibiting acetylcholinesterase on the muscle cells with AChR type 2.

👉 AP Bio 2017 FRQs

Experimental Design and Cellular Energetics

In flowering plants, pollination is a process that leads to the fertilization of an egg and the production of seeds. Some flowers attract pollinators, such as bees, using visual and chemical cues. When a bee visits a flower, in addition to transferring pollen, the bee can take nectar from the flower and use it to make honey for the colony. Nectar contains sugar, but certain plants also produce caffeine in the nectar. Caffeine is a bitter-tasting compound that can be toxic to insects at high concentrations. To investigate the role of caffeine in nectar, a group of researchers studied the effect of 0.1 mM caffeine on bee behavior. The results of an experiment to test the effect of caffeine on bees’ memory of a nectar source are shown in Table 1.

On the axes provided, construct an appropriately labeled graph to illustrate the effect of caffeine on the probability of bees revisiting a nectar source (memory).

Based on the results, describe the effect of caffeine on each of the following:

Short-term (10 minute) memory of a nectar source

Long-term (24 hour) memory of a nectar source

Design an experiment using artificial flowers to investigate potential negative effects of increasing caffeine concentrations in nectar on the number of floral visits by bees. Identify the null hypothesis, an appropriate control treatment, and the predicted results that could be used to reject the null hypothesis.

Researchers found that nectar with caffeine tends to have a lower sugar content than nectar without caffeine. Plants use less energy to produce the caffeine in nectar than they do to produce the sugar in nectar. Propose ONE benefit to plants that produce nectar with caffeine and a lower sugar content. Propose ONE cost to bees that visit the flowers of plants that produce nectar with caffeine and a lower sugar content.

Ecology (Ecological Succession)

Fires frequently occur in some ecosystems and can destroy all above-ground vegetation. Many species of plants in these ecosystems respond to compounds in smoke that regulate seed germination after a major fire. Karrikins (KAR) and trimethylbutenolides (TMB) are water-soluble compounds found in smoke that are deposited in the soil as a result of a fire. KAR and TMB bind to receptor proteins in a seed. In a study on the effects of smoke on seeds, researchers recorded the timing and percent of seed germination in the presence of various combinations of KAR and TMB. The results are shown in Figure 1. In a second investigation into the effect of available water on seed germination after a fire, researchers treated seeds with KAR or TMB. The treated seeds were then divided into two treatment groups. One group received a water rinse and the other group received no water rinse. The seeds were then incubated along with a group of control seeds that were not treated. The results are shown in the table.

The researchers made the following claims about the effect of KAR and the effect of TMB on seed germination relative to the control treatment.

KAR alone affects the timing of seed germination.

KAR alone affects the percentage of seeds that germinate.

TMB alone affects the timing of seed germination.

TMB alone affects the percentage of seeds that germinate.

Provide support using data from Figure 1 for each of the researchers’ claims.

Make a claim about the effect of rinsing on the binding of KAR to the receptor in the seed and about the effect of rinsing on the binding of TMB to the receptor in the seed. Identify the appropriate treatment groups and results from the table that, when compared with the controls, provide support for each claim.

There is intense competition by plants to successfully colonize areas that have been recently cleared by a fire. Describe ONE advantage of KAR regulation and ONE advantage of TMB regulation to plants that live in an ecosystem with regular fires.

Cell Communication and Cell Cycle (Gene Regulation and Expression)

Gibberellin is the primary plant hormone that promotes stem elongation. GA 3-beta-hydroxylase (GA3H) is the enzyme that catalyzes the reaction that converts a precursor of gibberellin to the active form of gibberellin. A mutation in the GA3H gene results in a short plant phenotype. When a pure-breeding tall plant is crossed with a pure-breeding short plant, all offspring in the F1 generation are tall. When the F1 plants are crossed with each other, 75 percent of the plants in the F2 generation are tall and 25 percent of the plants are short.

The wild-type allele encodes a GA3H enzyme with alanine (Ala), a nonpolar amino acid, at position 229. The mutant allele encodes a GA3H enzyme with threonine (Thr), a polar amino acid, at position 229. Describe the effect of the mutation on the enzyme and provide reasoning to support how this mutation results in a short plant phenotype in homozygous recessive plants.

Using the codon chart provided, predict the change in the codon sequence that resulted in the substitution of alanine for threonine at amino acid position 229.

Describe how individuals with one (heterozygous) or two (homozygous) copies of the wild-type GA3H allele can have the same phenotype.

Ecology (Energy Diagrams)

The table above shows how much each organism in an aquatic ecosystem relies on various food sources. The rows represent the organisms in the ecosystem, and the columns represent the food source. The percentages indicate the proportional dietary composition of each organism. High percentages indicate strong dependence of an organism on a food source.

Based on the food sources indicated in the data table, construct a food web in the template below. Write the organism names on the appropriate lines AND draw the arrows necessary to indicate the energy flow between organisms in the ecosystem.

In an effort to control the number of midges, an area within the ecosystem was sprayed with the fungus Metarhizium anisopliae, which significantly decreased the midge population. Based on the data in the table, predict whether the spraying of the fungus will have the greatest short-term impact on the population of the stoneflies, the caddisflies, or the hellgrammites. Justify your prediction.

Cellular Energetics

Microcystis aeruginosis is a freshwater photosynthetic cyanobacterium. When temperatures increase and nutrients are readily available in its pond habitat, M. aeruginosis undergoes rapid cell division and forms an extremely large, visible mass of cells called an algal bloom. M. aeruginosis has a short life span and is decomposed by aerobic bacteria and fungi. Identify the metabolic pathway and the organism that is primarily responsible for the change in oxygen level in the pond between times I and II AND between times III and IV.

Cell Communication and Cell Cycle (DNA Structure and Function)

A comet assay is a technique used to determine the amount of double-strand breaks in DNA (DNA damage) in cells. The nucleus of an individual cell is placed on a microscope slide coated with an agarose gel. An electric current is applied to the gel that causes DNA to move (electrophoresis), and the DNA is stained with a fluorescent dye. When viewed using a microscope, undamaged DNA from the nucleus appears as a round shape (the head), and the fragments of damaged DNA extend out from the head (the tail). The length of the tail corresponds to the amount of the damage in the DNA (see Figure 1).

To explain the movement of DNA fragments in the comet assay, identify one property of DNA and provide reasoning to support how the property contributes to the movement during the comet assay technique.

In a different experiment, cells are treated with a chemical mutagen that causes only nucleotide substitutions in DNA. Predict the likely results of a comet assay for this treatment.

Cellular Energetics (Anaerobic Respiration)

Many species of bacteria grow in the mouths of animals and can form biofilms on teeth (plaque). Within plaque, the outer layers contain high levels of oxygen and the layers closest to the tooth contain low levels of oxygen. The surface of the tooth is covered in a hard layer of enamel, which can be dissolved under acidic conditions. When the enamel breaks down, the bacteria in plaque can extract nutrients from the tooth and cause cavities.Certain types of bacteria (e.g., Streptococcus mutans) thrive in the innermost anaerobic layers of the plaque and are associated with cavities. Other types of bacteria (Streptococcus sanguinis) compete with S. mutans but are unable to thrive in acidic environments.

Identify the biochemical pathway S. mutans uses for metabolizing sugar and describe how the pathway contributes to the low pH in the inner layers of plaque.

Normal tooth brushing effectively removes much of the plaque from the flat surfaces of teeth but cannot reach the surfaces between teeth. Many commercial toothpastes contain alkaline components, which raise the pH of the mouth. Predict how the population sizes of S. mutans AND S. sanguinis in the bacterial community in the plaque between the teeth are likely to change when these toothpastes are used.

Cell Structure and Function Cell Transport

Estrogens are small hydrophobic lipid hormones that promote cell division and the development of reproductive structures in mammals. Estrogens passively diffuse across the plasma membrane and bind to their receptor proteins in the cytoplasm of target cells.

Describe ONE characteristic of the plasma membrane that allows estrogens to passively cross the membrane.

In a laboratory experiment, a researcher generates antibodies that bind to purified estrogen receptors extracted from cells. The researcher uses the antibodies in an attempt to treat estrogen-dependent cancers but finds that the treatment is ineffective. Explain the ineffectiveness of the antibodies for treating estrogen-dependent cancers.

👉 AP Bio 2016 FRQs

Cell Communication and Cell Cycle (Gene Regulation and Experimental Design)

Leucine aminopeptidases (LAPs) are found in all living organisms and have been associated with the response of the marine mussel, Mytilus edulis , to changes in salinity. LAPs are enzymes that remove N-terminal amino acids from proteins and release the free amino acids into the cytosol. To investigate the evolution of LAPs in wild populations of M. edulis , researchers sampled adult mussels from several different locations along a part of the northeast coast of the United States, as shown in Figure 1. The researchers then determined the percent of individuals possessing a particular lap allele, lap94 , in mussels from each sample site (table 1).

On the axes provided, construct an appropriately labeled bar graph to illustrate the observed frequencies of the lap 94 allele in the study populations.

Based on the data, describe the most likely effect of salinity on the frequency of the lap 94 allele in the marine mussel populations in Long Island Sound. Predict the likely lap 94 allele frequency at a sampling site between site 1 and site 2 in Long Island Sound.

Describe the most likely effect of LAP94 activity on the osmolarity of the cytosol. Describe the function of LAP94 in maintaining water balance in the mussels living in the Atlantic Ocean.

Marine mussel larvae are evenly dispersed throughout the study area by water movement. As larvae mature, they attach to the rocks in the water. Explain the differences in lap94 allele frequency among adult mussel populations at the sample sites despite the dispersal of larvae throughout the entire study area. Predict the likely effect on distribution of mussels in Long Island Sound if the lap94 allele was found in all of the mussels in the population. Justify your prediction.

Cell Communication and Cell Cycle and Ecology (Gene Regulation, Ecology, and Experimental Design)

Bacteria can be cultured in media with a carefully controlled nutrient composition. The graph above shows the growth of a bacterial population in a medium with limiting amounts of two nutrients, I and II.

Estimate the maximum population density in cells/mL for the culture. Using the data, describe what prevents further growth of the bacterial population in the culture.

Using the data, calculate the growth rate in cells/mL×hour of the bacterial population between hours 2 and 4.

Identify the preferred nutrient source of the bacteria in the culture over the course of the experiment. Use the graph to justify your response. Propose ONE advantage of the nutrient preference for an individual bacterium.

Describe how nutrient I most likely regulates the genes for metabolism of nutrient I and the genes for metabolism of nutrient II. Provide TWO reasons that the population does not grow between hours 5 and 6.

The graph above illustrates the percent dry weight of different parts of a particular annual plant (plants that live less than one year) from early May to late August. The percent dry weight can be used to estimate the amount of energy a plant uses to produce its leaves, vegetative buds, stems, roots, and reproductive parts (seeds, receptacles, and flowers).

Identify the direct source of the energy used for plant growth during the first week of May, and identify the part of the plant that grew the most during the same period.

Based on the data on the graph, estimate the percent of the total energy that the plant has allocated to the growth of leaves on the first day of July.

Compared with perennials (plants that live more than two years), annual plants often allocate a much greater percentage of their total energy to growth of their reproductive parts in any given year. Propose ONE evolutionary advantage of the energy allocation strategy in annual plants compared with that in perennial plants.

The figure represents the process of expression of gene X in a eukaryotic cell.

The primary transcript in the figure is 15 kilobases (kb) long, but the mature mRNA is 7 kb in length. Describe the modification that most likely resulted in the 8 kb difference in length of the mature mRNA molecule. Identify in your response the location in the cell where the change occurs.

Predict the length of the mature gene X mRNA if the full-length gene is introduced and expressed in prokaryotic cells. Justify your prediction.

Ecology (Ecological Relationships)

The graph above shows the mass of plants from two different species over time. The plants grew while attached to each other. The plants were separated at the time indicated by the vertical line in the graph. Using template 1, graph the predicted shape of the plant-mass lines after separation of the two plants if the plants were in an obligate mutualistic relationship. On template 2, graph the predicted shape of the plant-mass lines if the species 2 plant was a parasite of the species 1 plant. Justify each of your predictions.

Living and dead organisms continuously shed DNA fragments, known as eDNA, into the environment. To detect eDNA fragments in the environment, the polymerase chain reaction (PCR) can be used to amplify specific eDNA fragments. eDNA fragments of different lengths persist in the environment for varying amounts of time before becoming undetectable (Figure 1). To investigate whether silver carp, an invasive fish, have moved from a nearby river system into Lake Michigan, researchers tested water samples for the presence of eDNA specific to silver carp (Figure 2).

Justify the use of eDNA sampling as an appropriate technique for detecting the presence of silver carp in an environment where many different species of fish are found. Propose ONE advantage of identifying long eDNA fragments as opposed to short fragments for detecting silver carp.

The researchers tested a large number of water samples from Lake Michigan and found eDNA specific to silver carp in a single sample in the lake, as indicated in Figure 2. The researchers concluded that the single positive sample was a false positive and that no silver carp had entered Lake Michigan. Provide reasoning other than human error to support the researchers’ claim.

In a certain species of plant, the diploid number of chromosomes is 4 (2n = 4). Flower color is controlled by a single gene in which the green allele ( G ) is dominant to the purple allele ( g ). Plant height is controlled by a different gene in which the dwarf allele ( D ) is dominant to the tall allele ( d ). Individuals of the parental ( P ) generation with the genotypes GGDD and ggdd were crossed to produce F1 progeny.

Construct a diagram below to depict the four possible normal products of meiosis that would be produced by the F1 progeny. Show the chromosomes and the allele(s) they carry. Assume the genes are located on different chromosomes and the gene for flower color is on chromosome 1.

Predict the possible phenotypes and their ratios in the offspring of a testcross between an F1 individual and a ggdd individual.

If the two genes were genetically linked, describe how the proportions of phenotypes of the resulting offspring would most likely differ from those of the testcross between an F1 individual and a ggdd individual.

Researchers conducted a study to investigate the effect of exercise on the release of prolactin into the blood. The researchers measured the concentration of prolactin in the blood of eight adult males before (T = 0 hour) and after one hour (T = 1 hour) of vigorous exercise. As a control, the researchers measured the concentration of blood prolactin in the same group of individuals at the same times of day one week later, but without having them exercise. The results are shown in Figure 1.

Justify the use of the without-exercise treatment as the control in the study design.

Using evidence from the specific treatments, determine whether prolactin release changes after exercise. Justify your answer.

👉 AP Bio 2015 FRQs

Gene Expression and Regulation, Ecology (Symbiosis, Genetic Expression)

Many species have circadian rhythms that exhibit an approximately 24-hour cycle. Circadian rhythms are controlled by both genetics and environmental conditions, including light. Researchers investigated the effect of light on mouse behavior by using a running wheel with a motion sensor to record activity on actograms, as shown in Figure 1. For the investigation, adult male mice were individually housed in cages in a soundproof room at 25°C. Each mouse was provided with adequate food, water, bedding material, and a running wheel. The mice were exposed to daily periods of 12 hours of light (L) and 12 hours of dark (D) (L12:D12) for 14 days, and their activity was continuously monitored. The activity data are shown in Figure 2. After 14 days in L12:D12, the mice were placed in continuous darkness (DD), and their activity on the running wheel was recorded as before. The activity data under DD conditions are shown in Figure 3.

The nervous system plays a role in coordinating the observed activity pattern of the mice in response to light-dark stimuli. Describe ONE role of each of the following anatomical structures in responding to lightdark stimuli.

A photoreceptor in the retina of the eye

A motor neuron

Based on an analysis of the data in Figure 2, describe the activity pattern of the mice during the light and dark periods of the L12:D12 cycle.

The researchers claim that the genetically controlled circadian rhythm in the mice does not follow a 24-hour cycle. Describe ONE difference between the daily pattern of activity under L12:D12 conditions (Figure 2) and under DD conditions (Figure 3), and use the data to support the researchers’ claim.

To investigate the claim that exposure to light overrides the genetically controlled circadian rhythm, the researchers plan to repeat the experiment with mutant mice lacking a gene that controls the circadian rhythm. Predict the observed activity pattern of the mutant mice under L12:D12 conditions and under DD conditions that would support the claim that light overrides the genetically controlled circadian rhythm.

In nature, mice are potential prey for some predatory birds that hunt during the day. Describe TWO features of a model that represents how the predator-prey relationship between the birds and the mice may have resulted in the evolution of the observed activity pattern of the mice.

Cellular Energetics (Cellular Respiration, ATP, Krebs Cycle, Glycolysis)

Cellular respiration includes the metabolic pathways of glycolysis, the Krebs cycle, and the electron transport chain, as represented in the figures. In cellular respiration, carbohydrates and other metabolites are oxidized, and the resulting energy-transfer reactions support the synthesis of ATP.

Using the information above, describe ONE contribution of each of the following in ATP synthesis.

Catabolism of glucose in glycolysis and pyruvate oxidation

Oxidation of intermediates in the Krebs cycle

Formation of a proton gradient by the electron transport chain

Use each of the following observations to justify the claim that glycolysis first occurred in a common ancestor of all living organisms.

Nearly all existing organisms perform glycolysis.

Glycolysis occurs under anaerobic conditions.

Glycolysis occurs only in the cytosol.

A researcher estimates that, in a certain organism, the complete metabolism of glucose produces 30 molecules of ATP for each molecule of glucose. The energy released from the total oxidation of glucose under standard conditions is 686 kcal/mol. The energy released from the hydrolysis of ATP to ADP and inorganic phosphate under standard conditions is 7.3 kcal/mol. Calculate the amount of energy available from the hydrolysis of 30 moles of ATP. Calculate the efficiency of total ATP production from 1 mole of glucose in the organism. Describe what happens to the excess energy that is released from the metabolism of glucose.

The enzymes of the Krebs cycle function in the cytosol of bacteria, but among eukaryotes the enzymes function mostly in the mitochondria. Pose a scientific question that connects the subcellular location of the enzymes in the Krebs cycle to the evolution of eukaryotes.

Natural Selection, Chemical Structure of Life (Amino Acids, Phylogenic Tree)

The amino acid sequence of cytochrome c was determined for five different species of vertebrates. The table below shows the number of differences in the sequences between each pair of species.

Using the data in the table, create a phylogenetic tree on the template provided to reflect the evolutionary relationships of the organisms. Provide reasoning for the placement on the tree of the species that is least related to the others.

Identify whether morphological data or amino acid sequence data are more likely to accurately represent the true evolutionary relationships among the species, and provide reasoning for your answer.

Cell Communication and Cell Cycle (Mitosis, Meiosis)

Both mitosis and meiosis are forms of cell division that produce daughter cells containing genetic information from the parent cell.

Describe TWO events that are common to both mitosis and meiosis that ensure the resulting daughter cells inherit the appropriate number of chromosomes.

The genetic composition of daughter cells produced by mitosis differs from that of the daughter cells produced by meiosis. Describe TWO features of the cell division processes that lead to these differences.

Cellular Energetics (Photosynthesis)

Phototropism in plants is a response in which a plant shoot grows toward a light source. The results of five different experimental treatments from classic investigations of phototropism are shown above.

Give support for the claim that the cells located in the tip of the plant shoot detect the light by comparing the results from treatment group I with the results from treatment group II and treatment group III.

In treatment groups IV and V, the tips of the plants are removed and placed back onto the shoot on either a permeable or impermeable barrier. Using the results from treatment groups IV and V, describe TWO additional characteristics of the phototropism response.

Ecology (Population Dynamics)

In an attempt to rescue a small isolated population of snakes from decline, a few male snakes from several larger populations of the same species were introduced into the population in 1992. The snakes reproduce sexually, and there are abundant resources in the environment. The figure below shows the results of a study of the snake population both before and after the introduction of the outside males. In the study, the numbers of captured snakes indicate the overall population size.

Describe ONE characteristic of the original population that may have led to the population’s decline in size between 1989 and 1993.

Propose ONE reason that the introduction of the outside males rescued the snake population from decline.

Describe how the data support the statement that there are abundant resources in the environment.

Cell Communication and Cell Cycle (Cell signaling, transmissions)

Smell perception in mammals involves the interactions of airborne odorant molecules from the environment with receptor proteins on the olfactory neurons in the nasal cavity. The binding of odorant molecules to the receptor proteins triggers action potentials in the olfactory neurons and results in transmission of information to the brain. Mammalian genomes typically have approximately 1,000 functional odorant-receptor genes, each encoding a unique odorant receptor.

Describe how the signal is transmitted across the synapse from an activated olfactory sensory neuron to the interneuron that transmits the information to the brain.

Explain how the expression of a limited number of odorant receptor genes can lead to the perception of thousands of odors. Use the evidence about the number of odorant receptor genes to support your answer

Cell Communication and Cell Cycle (Cell Communication, Immune System)

An individual has lost the ability to activate B cells and mount a humoral immune response.

Propose ONE direct consequence of the loss of B-cell activity on the individual’s humoral immune response to the initial exposure to a bacterial pathogen.

Propose ONE direct consequence of the loss of B-cell activity on the speed of the individual’s humoral immune response to a second exposure to the bacterial pathogen.

Describe ONE characteristic of the individual’s immune response to the bacterial pathogen that is not affected by the loss of B cells.

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Excel at Science

• Feb 16, 2021

AP Biology Past FRQs by Topic

Updated: Jan 31

**Updated on 1/31/24 to include the 2022-23 FRQ exams!**

If you are looking for past AP Biology free-response questions (FRQs) that are organized by topic, then you have come to the right place. In this post, we have linked every freely available past FRQ there is from College Board and organized it into the following major topics of AP Biology .

(Please note that we are not associated with College Board and are simply sharing the resources they have made available to students.)

Biochemistry

Metabolism & energetics.

Physiology (note that this topic will not be tested on the official AP Biology exam this year in 2021, although many questions about physiology could also cover concepts that will be tested)

Experiment design & data analysis

Need more AP-style practice problems?

Intensively doing and reviewing practice questions is proven to be much more effective than spending hours studying. Check out our AP Bio Practice Portal , which is an easy-to-use database of 300+ AP-style MCQ and FRQ practice questions. Students love the Practice Portal because it includes answers and explanations for every problem, tracks progress, and saves time from Googling practice problems.

Try the Practice Portal >

How to make the most of past frqs from college board.

As noted above, the diversity of organisms, plants, and physiology will not be on the 2021 AP Biology exam. However, the exam could include questions about topics or hypothetical situations that are related to those topics. One great example is cell communication, which is used in multiple systems inside our bodies. Let’s say an FRQ was to appear about the immune system and how the immune cells communicate. That would be fair game as long as the question focuses on the cell signaling part, not the details of the immune system. If the question requires some background knowledge about the immune system, it will be provided.

If you want to do a whole practice FRQ set just like the ones on the real exam (which we highly recommend), all the freely available past FRQs by year are available here on the College Board website. Tip: time yourself and take the practice FRQ set in an environment that mimics how you imagine your actual testing environment to be.

If you would like to focus on a particular topic, then the section coming up is for you. Some FRQs will show up under multiple topics because they truly do test students’ understanding of multiple different topics.

Tip : Whether you are doing individual free-response questions or doing a full problem set in one go, it is extremely important and effective to do test corrections! Don’t only consult the scoring guidelines and model responses when you have no clue how to answer a question. You should be checking them for all the FRQs you do. When you find a difference between your answer and the scoring guidelines, it is important that you pause and analyze why your response is incorrect. Take the time to understand your mistakes and see how your answer could have been better. This will help you boost your scores the most efficiently.

AP BIOLOGY FRQs BY TOPIC

Below are the linked FRQs organized by topic. The header for each topic will also lead you to the corresponding study guide that will help you review the unit in detail!

Basic and organic chemistry concepts do not come up often on the FRQs (but of course, it’s better to be prepared). The properties of water and macromolecules come up occasionally.

2017 #7 and 8

Includes cell structure and function, cell transport and the proteins involved.

2019 #3 and 8

2018 #2, 6, and 8

2006 #1, 3, and 4

2001 #1 and 4

(study guide coming soon!)

This unit includes enzymes, cellular respiration, and photosynthesis.

2023 #2 (cell respiration & photosynthesis)

2023 #4 (photosynthesis)

2022 #3 (enzymes)

2021 #3 (cell respiration)

2019 #3 (cell respiration)

2018 #2 (cell respiration)

2017 #7 (cell respiration)

2017 #5 (photosynthesis)

2015 #2 (cell respiration)

2013 #2 (photosynthesis) and 4 (cell respiration & photosynthesis)

2012 #2 (cell respiration) and 4 (cell respiration & photosynthesis)

2010 #2 (enzymes)

2007 #3 (photosynthesis)

2006 #4 (photosynthesis)

2005 #1 (cell respiration & photosynthesis)

2004 #3 (photosynthesis)

Cell cycle & cell signaling

This topic has shown up more frequently and in more difficult FRQs in recent years, especially cell communication. The trend will most likely continue so definitely prioritize reviewing and practicing this topic!

2023 #1 (cell communication)

2022 #1 (cell communication)

2022 #2 (cell cycle, meiosis)

2021 #1 (cell communication)

2019 #4 (cell communication)

2018 #8 (cell communication)

2017 #8 (cell communication)

2016 # 7 (cell division)

2015 # 4 (cell division)

2015 #5 and 7 (cell communication)

2013 #8 (cell communication)

2011 #1B (cell division)

2010 #1 (cell communication)

2006 #1B (cell division)

2004 #1 (cell division)

Genetics, Gene Expression and Regulation

Genetics Pt 1 and Genetics Pt 2 Study Guides

This section includes the classic Mendelian genetics, with Punnett squares, crosses, and Mendel’s laws. It also includes DNA replication, protein synthesis, and gene expression regulation for both eukaryotes and prokaryotes.

2023 #6 (gene expression)

2022 #6 (protein synthesis, gene expression)

2021 #6 (gene expression)

2021 #2 (heredity + pedigrees)

2020 #1 parts a-b

2019 #1 and 3

2018 #1, 4, and 7

2016 #4 and 7

2023 #5 (Cladistics)

2022 #4 (speciation)

2020 #1 parts f-j

2015 #3 and 6

2014 #2 and 4

2015 #2 (nervous system)

2014 #2 (immune system) and 6 (musculoskeletal system) and 7

2017 #2, 4, and 7b

2016 #3 and 5

2014 #3 and 4

Experimental design & analysis

This is an additional section that isn’t focused on any particular topic or has significant data analysis involved. While most FRQs do pertain to a specific topic(s), some are simply there to test your knowledge of experimental design and understanding of statistical concepts such as performing Chi-Square tests and interpreting error bars on graphs. These types of questions have become more and more common on the AP exam, so it is important to feel comfortable and confident with them.

2023 #6 (data analysis)

2022 #3 (experiment design)

2020 #1 parts c-e

2016 #2 , 6 and 8

2014 #1 and 5

2013 #1 and 7

Hope these organized FRQs saved you some time so you can focus more on actually doing them and practicing! You can easily share this post with friends who may find it helpful as well.

How to Improve AP Biology FRQ Scores, Fast

Do a lot of FRQ practice problems and review the answers! Practice is key, especially for a subject as dense as AP Bio. Check out the AP Bio Practice Portal , which is our popular vault of 300+ AP-style MCQ and FRQ problem sets with answers and explanations for every question. Don't waste any more time Googling practice problems or answers - try it out now!

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AP® Biology

How to answer ap® biology free response questions.

• The Albert Team
• Last Updated On: March 1, 2022

The free response section can make or break any student’s AP® Biology exam score. If you’re wondering what the best tips and tricks for answering AP® Biology free response questions, you’ve come to the right place.

In this article, we extensively cover must know tips for writing effective AP® Biology FRQs, common mistakes made by students when analyzing past AP® Biology scoring guidelines, and how to use past AP® Biology free response questions to start practicing for your exam.

Read on to get the complete scoop when it comes to succeeding on your AP® Biology exam review.

What We Review

5 Steps on How to Write Effective AP® Biology Free Responses

In this section, we’ll give you a strategy to start writing AP® Biology free responses that score you points. 

1. Understand how points are awarded by reviewing the AP® Biology rubrics.

The first step to crafting good AP® Biology free responses that score you points is understanding how points are distributed. The easiest way to do this is by going to the College Board’s AP® Central website and navigating to their past released exams . 

From here, you’ll want to open up the scoring guidelines — these will detail what points were awarded for different parts of AP® Biology free response questions. 

Here’s a screenshot from the 2019 released exam: 

Source: College Board

As you can see in this first section 1 (a), students receive two points, one for properly circling the transcription on the template pathway, and another point for properly identifying the molecule.

2. Underline or circle every bolded and capitalized word.

One of the nice parts of the AP® Biology free response section is that the College Board draws attention to what they are asking you to answer. This means you need to make sure you answer it! 

Bolded and capitalized words are often the easiest way to figure out the root of the question. Typically you can break down how much each question is worth from the bolded and capitalized words. 

One of our best test taking tips is to make sure you check off or star next to the word after you’ve answered it in your free response. This serves as a visual checklist for you to make sure you answered all parts of the question. 

3. Understand what the question is asking you and identify common AP® Biology directive words.

One of the easiest ways students get tripped up in their AP® Biology exam review is not actually answering the question that the test makers are asking. It’s a commonly cited piece of advice from the College Board readers. 

Here are nine common AP® Biology question stems (directive words) to make sure you know cold:

• Calculate: This is where you’ll be asked to solve a problem. Two points are typically awarded for these parts, one for the right answer and one for showing your work. 
• Compare: This is where you must outline similarities between two or more things. It’s important you specifically only outline similarities; don’t get this confused with contrast!
• Contrast : This is where you must show the differences between two or more things.
• Discuss: This is where you’ll want to outline pros and cons on a topic, process, theory or technique. 
• Describe: This sort of question assesses your ability to characterize something; for example: the functions of a certain part of a cell. 
• Explain: This is where you need to demonstrate your ability to make something understandable. 
• Identify: This is where you will need to give a direct answer to the question. It’s usually closely related to reading a diagram or graphical representation. 
• Interpret: This is where you need to analyze something critically or explain something that isn’t clear. 
• Justify: This is where you must explain why something may happen. This is testing similar skills to interpret and explain. 

Stems like calculate, explain, and justify are often associated with two-point problems. 

Notice how some of these stems are open-ended. For example, discuss, describe, explain, and interpret are all generally pretty-open ended. Typically, this should clue you in that your answer should be thorough for this part of the problem. For example, if you’re asked to explain why a certain result may occur from an experiment — you would need to exhaustively cover the set up of the experiment, as well as what makes that particular experimental design an effective way to measure the dependent variable. 

Make sure you do not make the mistake of only providing a single sentence answer when so many points are at stake! 

AP® Biology students most often lose 5+ points when it comes to the first and second problems in the free response section. These are points you can’t get back, and can dramatically impact the way you score. 

There are a handful of other common stems — be sure to review the past AP® Biology released exams to familiarize yourself with them. 

4. Be succinct in your AP® Biology free responses.

This isn’t an AP® English Language free response essay. One of the most common mistakes AP® Biology students make when answering free response questions is thinking if they just write a lot, they can score more points. This is not true. 

For example, if the question asked you to identify four properties of something and you list out nine, you will only get points for the first four you stated. 

It is not the responsibility of your AP® reader to figure out what you meant. It is your responsibility as the AP® Biology test taker to communicate clearly through your writing. 

A few principles to remember when writing your AP® Biology free responses:

• Don’t restate the question. This is unnecessary and will not score you points. 
• Write in complete sentences.
• If doing a calculation, make sure you clearly identify your final answer (this is most easily done by boxing your answer), AND show your work. A point is typically awarded for showing your work.
• Once you answer the question, move on. One of the most common mistakes AP® Biology students make is by making a contradicting statement after they stated the right answer. If there is a contradicting statement made, you can lose out on points. 
• Remember the prior tip for graphing as well. If it asks you to plot, put the data points in the graph. If the question asks you to graph, draw a line or curve. Do not extend beyond the provided data unless you’re explicitly asked in the question to predict or extrapolate a result. 
• When graphing, make sure you follow graphing conventions. This means titling your chart, labeling your axes, scaling appropriately, and selecting the right type of graph.
• Be mindful of your handwriting. While it’s not formally part of the grading process, if your AP® Reader cannot decipher your handwriting in the limited amount of time they have grading your exam, you are making it harder for them to give you points. 

A final overarching principle is to make sure you practice completing your thoughts within a prompt. This has been called “closing the loop” and it is one of the most frequent mistakes students make here is when they’re asked for example to state the direction something is changing in the prompt, but then fail to do so. 

5. Practice, practice, and then practice some more.

Mastering the AP® Biology free response section comes down to two things: understanding how the free response is graded, and then learning how to answer questions that fit those expectations. 

Sometimes students do a great job of learning the rubrics, but don’t practice enough on actually writing sample responses or vice versa. When you’re starting your AP® Biology free response review, it’s helpful to first try out a past set of released questions, then grade yourself with the scoring guidelines. 

See how long it took you to answer each question, how effective you were at answering the actual question posed, and where you missed out on points. 

After a few times of doing this, you’ll begin to be more mindful of what the test makers are looking for in your responses.

Return to the Table of Contents

25 AP® Biology FRQ Tips to Scoring a 4 or 5

Now that we’ve covered how to write effective AP® Biology free responses, we’ll shift gears to cover some tips and tricks to maximizing your FRQ score. 

• When interpreting data, make sure you provide reasoning to support a claim. In recent years of exams, students have struggled in understanding the two-part nature of questions that ask to explain or justify something.
• Interpreting and constructing models are different skills. It is not enough just to be able to create a phylogenetic tree. A student needs to understand what the model they construct actually says. 
• Practice applying fundamental knowledge of basic biology to giving an explanation for why you chose to present data in a certain way. 
• Be specific but with purpose ! Sometimes students include unnecessary specificity that doesn’t actually answer what the question is asking. Provide your reasoning — don’t just repeat something given in the prompt.
• Use “claim-evidence-reasoning”. This is where you break down an argument into these parts to make your point more clear. 
• When asked to make a comparison, make sure to answer the before and after state of the comparison. 
• When reviewing commonly tested topics such as the modeling of a cell signaling pathway, make sure you are able to describe each step of the pathway and anticipate what might happen if a particular step was activated or inhibited.
• Practice reading multiple types of tables, then make sure you also practice creating your own tables with data. Remember the earlier tip to follow standard graphing conventions. Students have missed points in recent years for mistakes like forgetting to have units in their axes or missing labels.
• Building on the prior tip, practice creating graphs from different sources of information — for example, you may have to draw a diagram from a narrative description. You should feel comfortable with creating different types of graphs like bar, dual Y axes, line, semi-log, etc. 
• Practice incorporating evidence from your own knowledge of biology — this can help in thoroughly answering questions that ask you to justify or interpret something.
• Always be thinking about how to apply prior things you’ve learned to a new situation — the College Board is known for asking AP® Biology questions that cover something you’ve never directly learned before, but they are often questions that require you to apply one or two concepts you have previously had exposure to. This was a common mistake made by students in the 2019 exam on question 1 when students often missed points for not applying changes in molecular processes to ecological relationships. 
• Remember that natural selection has two notions: survival AND reproduction. This was a commonly missed point over the course of the last few years. 
• When answering experimental design questions, make sure you practice being specific in stating the change that may occur in an experiment. It’s not enough just to say that a change will occur. Make direct comparisons to the control group. When you fail to explain the different parts of an experiment and how it is designed, it makes it difficult for the reader to believe that you truly understand how to build a meaningful experiment.
• Questions that test you on experimental design should always have a control, a variable to test in a few ways, a hypothesis, expected results, and clear graphs.
• Know the difference between a dependent variable and an independent variable. There can be several independent variables but there can only be one dependent variable in a well-constructed experiment. 
• Remember that hypotheses (predictions) should compare the experimental group to a control group. It is not enough just to say something like “X will change” — it is better to say “X will change by being more Y” — notice how in this latter response, we’re being intentional and specific with directionality of the change. 
• If you don’t remember the exact name of a concept or how to spell it, try describing it or giving your best shot at spelling it. You can sometimes earn points for defining relevant terms. 
• Answer the AP® Biology free responses questions any way you’d like. All you need to do is make sure you’re making clear which question you are answering. Taking this approach is a common strategy for managing your time effectively. 
• Keep your opinion out of your free response answer. Your AP® Bio free responses should be backed by things you learned in class and actual science.
• Wear a watch when practicing and taking the actual AP® Biology exam. You need to be familiar with how to pace yourself in different parts of the FRQs. It’s common sense, but longer questions deserve more time while shorter questions should take you less time.
• If you’re given a parameter, follow it…when questions ask you to state something in a sentence or two, you should not write four sentences. Follow directions!
• Make sure you explain terms when you use them — assume your grader knows little about AP® Biology. 
• Use a black or blue ink pen. Doing so makes it easier for your AP® Biology exam to be graded.
• Try every question. One of the most common pieces of advice from AP® Biology teachers is to make sure you put something down for every question. You do not lose points for getting things wrong, but you miss out entirely on points for not answering a question at all.
• Know your commonly tested diagrams cold. Concepts that often have related diagrams like cell signaling pathways, or Punnett squares are topics to make sure you understand when given different forms of information. For example, with Punnett squares you should be comfortable describing all outcomes in a variety of ways (such as in percentages and ratios, as phenotypes or genotypes). You should be comfortable creating Punnett squares when given information about the parent generation, or the F1 generation. 

Wrapping Things Up: How to Write AP® Biology FRQs

We’ve covered a lot of ground when it comes to answering AP® Biology free response questions. Here are a few key things to remember: 

• Know how AP® Biology FRQ points are rewarded.
• Build the habit of identifying the sources of points in questions. Circle or underline these to figure out how valuable different parts of a question are. 
• Understand the question being asked — learn the directive words the College Board often uses and what they are asking for.
• Master commonly tested skills such as experimental design and graphing (including interpretation of graphs). 
• Review commonly tested AP® Biology topics. Refer to the curriculum and exam description to see the percentage breakdown of different units. 
• Be specific and succinct in your responses. This is not an AP® English Language essay.
• Try every question and be intentional in the order in which you answer each one. Tackle the questions you feel most confident in first.  

We hope you’ve found this extensive guide helpful for your AP® Biology exam review. If you’d like additional free response or multiple choice practice, check out Albert for hundreds of original standards-aligned practice questions.

If you found this post helpful, you may also like our AP® Biology tips here or check out our AP® Biology score calculator here .

We also have an AP® Biology review guide here .

Need help preparing for your AP® Biology exam?

Albert has hundreds of AP® Biology practice questions, free response, and full-length practice tests to try out.

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Advanced Placement (AP)

AP Biology is known for being one of the tougher AP exams , and, for most students, the free-response section is the hardest part of the test. In 2021 , the average score for every free-response question was less than a 50%! However, knowing what to expect can make it easier to get a great score on AP Biology FRQ. And in this guide, we explain everything you need to know to ace this section. Read on to learn the format of AP Biology FRQ, what graders are looking for, what the questions will look like, and what you can do to be well-prepared on exam day.

What's the Format of the AP Biology Free Response Section?

The AP Biology exam has two sections: multiple choice and free response. The free-section comes second and contains six questions:

• Two long-response questions , both with a focus on analyzing experimental results. The second long question will require you to create a graph.
• Four short-answer questions on the following topics in this order:
• Scientific Investigation
• Conceptual Analysis
• Analysis of Model or Visual Representation
• Analysis of Data

Additionally:

• The free-response section is 90 minutes long
• It's worth 50% of your total score
• You're able to use the AP Biology formula sheet for the entire section

Long questions are worth 8-10 points each, whereas short-answer questions are each worth 4 points. It's recommended that you spend about 25 minutes on each long question and about 10 minutes on each short question (although you'll decide yourself how long you spend on each question).

The AP Biology test expects you to know how to:

• Understand how graphical and mathematical models can be used to explain biological principles and concepts
• Make predictions and justify events based on biological principles
• Implement your knowledge of proper experimental design
• Interpret data

AP Biology Sample Free Response Questions 

Now we'll go through two AP Biology free response example questions: one long question and one short question. These questions both were used for the 2021 AP Biology exam . You can see answers and scoring for each of the 2021 AP Biology FRQs here .

Long Question

First let's look at one of the long questions. This is Question 2, so remember you'll need to create a graph for at least one part of it. The entire question is worth 8 points.

Part A (1 point)

Part B (4 points)

First, you need to create a graph based on the data in Table 1. The graph is worth 3 points: 1 for axis labels, 1 for the correct plotting in the bar graph, and 1 for the error bars. Here's an example of a graph that would get full points:

Part C (1 point)

Part D (2 points)

• The data do not support the claim because females III-2 and III-6 have the disorder and, if inheritance was X-linked recessive, they'd only have the disorder if their father II-1 had the disorder, which he does not.
• The data supports mitochondrial inheritance because all of the offspring of individual II-2 , not just the sons, have the disorder.

Giving one of those answers is worth one point.

Short Question

Next is a short question. It's question 3 in the free-response section which means it will focus on scientific investigation. It's worth a total of four points.

Part B (1 point)

• The researchers must run the experiment without adding resveratrol.
• The researchers must treat the cells with DMSO alone.

There are two potential answers; you only need to include one:

• No ATP production
• Reduced ATP production

Part D (1 point)

For Part D, you must state that more electrons can be transferred so that more oxygen is required as the final electron acceptor.

Where to Find AP Biology FRQs

Taking practice tests and answering practice questions is one of the best ways to prepare for any AP exam, including AP Biology FRQs. Fortunately, the College Board, who creates and administers AP courses and exams, has made dozens of old AP Bio FRQs available for free online. Because there are so many official FRQs available, we recommend only using them instead of looking online for unofficial questions (those not created by the College Board), which can be hit or miss in terms of quality. However, if you're using an AP Biology prep book, they often have solid FRQs. For advice on which prep book to get, check out our guide on the best AP Biology prep books.

Here are links to the FRQs:

Additionally, the AP Biology Course and Exam Description includes two up-to-date FRQs, beginning on page 206.

Note that, until 2020, the AP Bio exam had six short-answer questions instead of the current four. This means that questions from 2019 and earlier will have a different format and slightly different content. They can still be useful to study, but be aware of the differences between them and the current free-response section.

4 Tips for AP Biology FRQs

When you're studying for AP Bio FRQs and actually taking the exam, there are a lot of things to remember to ensure you do your absolute best. Keep these four tips in mind throughout the year and on exam day.

#1: Know Your 13 Required Labs

There are 13 labs you're required to complete during the AP Biology course. Questions that relate at least in part to these labs make up 25% of the AP Biology exam. It’s important to understand how these labs are conducted and how the principles behind them relate to the main ideas of the course. This will help in answering both free-response and multiple-choice questions that deal with lab scenarios on the test. There's a nice overview of each of the 13 labs on this site that can refresh your memory, and we link to in-depth explanations of each of the labs in our AP Biology study guide .

You should also know general lab skills. Many free-response questions ask you to identify the components of a proposed experiment (dependent and independent variables) or to design a lab to test a certain hypothesis. You might have forgotten about the labs you did toward the beginning of the year, so take extra care to go over them. Make sure that you understand just how they were conducted and what the results mean.

#2: Eliminate Irrelevant Information

Free-response AP Biology questions (especially the long questions) include lots of scientific terminology and visual aids, and this kind of format might be intimidating if you’re not used to it. It’s important to practice sorting through this jumble of information so that you can quickly get to the root of the question rather than obsessing over small details you don’t understand.

Try underlining important words and phrases in the question to help you stay focused on the main points and avoid misleading distractions.

You should also practice responding to free-response questions in a straightforward way without any unnecessary fluff. Remember, this isn’t an English test; the graders are just looking for clear facts and analysis. Make it easy for them to give you points!

#3: Draw During Studying

If you're feeling shaky on your knowledge of a process or system in AP Biology, one helpful strategy is to draw it. This will both reinforce what you know and highlight what you still need to work on learning. Once you're able to draw an accurate diagram of a system or process without looking at your notes, you can feel confident that you know exactly how it works.

For example, you could challenge yourself to draw a diagram of a cell membrane, label its different components, and explain their significance. You could also draw a process like mitosis that happens in clear visual stages, or a more complex process like cellular respiration where you might focus on one aspect at a time (glycolysis, Krebs cycle, electron transport chain). You can also apply this tip during the exam, if you need help visualizing part of an AP Bio FRQ.

#4: Pay Attention to the Clock

Time is always tight on AP exams. For the AP Biology free response section, you get 90 minutes to answer six questions. It can be easy to get caught up on one question and suddenly realize you're nearly out of time but haven't had a chance to look at some of the questions, let alone answer them. Don't let this happen to you! We recommend spending 25 minutes on each of the two long questions and 10 minutes on each of the four short questions. You don't need to keep perfectly to that plan, but don't get too far off it, either. 

At the very least, make note of where you are halfway through the free-response section (that's 45 minutes in). If you're roughly halfway finished with the section (taking into account that long questions take about twice as much time to complete as short questions), you're doing well. If you're significantly behind that, you know you need to pick up the pace.

Also, don't feel you need to answer the FRQ in the order they're listed. We recommend skimming through each of the questions at the start of the section, then tackling the questions that seem easiest first so you can spend more time on trickier questions.

Summary: Acing the AP Biology Free Response Section

The AP Biology free-response section can be tough, but if you prepare well for it, you can go into exam day confident and knowing what to expect. The section consists of two long questions and four short questions, lasts 90 minutes, and is worth half of your total score. You'll need to create a graph for the second AP biology FRQ. Old exam questions are a great study resource and, when you're preparing for the free-response section, keep these four tips in mind:

• Know your labs
• Eliminate irrelevant information
• Make drawings while studying
• Stay aware of time

What's Next?

How should you study for the AP Biology exam? Our expert article goes over all 5 steps to take during your AP Biology review.

What is the rest of the AP Biology exam like? Our article on the AP Biology exam goes over every question type you can expect to see as well as tips for answering them.

Looking for an easier AP class than Biology? Learn which AP classes tend to be the least challenging for students .

Christine graduated from Michigan State University with degrees in Environmental Biology and Geography and received her Master's from Duke University. In high school she scored in the 99th percentile on the SAT and was named a National Merit Finalist. She has taught English and biology in several countries.

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