---
title: "AP Biology Experimental Results FRQ Practice"
description: "128 Interpreting and Evaluating Experimental Results questions written in the AP format, each scored part by part."
canonical: "https://fiveable.me/ap-bio/frqs/experimental-results"
type: "frq-type-practice"
subject: "AP Biology"
---

# AP Biology Experimental Results FRQ Practice

## What the Experimental Results FRQ asks

This is FRQ 1 on the AP Biology exam, one of the two long FRQs. You get a research scenario with figures and answer four parts about the biology, the experiment’s design, the data, and the researchers’ claims.

- **25 min**: suggested writing time
- **9 points**: across parts A to D
- **50%**: of your score, for all six FRQs

| Part | What it asks | Points |
| --- | --- | --- |
| A: Biology concept | Describe a concept or process behind the experiment | 1 |
| B: Experimental design | Identify a variable, justify a control, and describe the data | 3 |
| C: Data analysis | Identify a variable, read values from the data, and calculate | 3 |
| D: Claims | Support a claim with data and justify it with biology | 2 |

## How Experimental Results FRQ practice works

1. **Read the full question.** The research scenario, the figures, and all four parts, A through D, laid out the way the exam shows them.
2. **Write on a 25-minute timer.** The time to plan for on exam day. Pause it or turn it off, and your response saves as you go.
3. **Submit for a score out of 9.** Your response is scored against the scoring guidelines written for that question. Your first score is included.

## All 128 questions

### Unit 1: Chemistry of Life (8)
- [Amino acid R-groups determine protein tertiary structure](/ap-bio/frq-practice?id=6983e8c3ebf1103b6c5281a2&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Polar water molecules form hydrogen bonds](/ap-bio/frq-practice?id=6983ea08ebf1103b6c5281b1&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Disulfide bonds and amino acid interactions stabilize protein structure](/ap-bio/frq-practice?id=6983eaf8ebf1103b6c5281bb&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Amino acid R-groups and protein tertiary structure](/ap-bio/frq-practice?id=6983ebe7ebf1103b6c5281c8&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Amino acid R-groups and tertiary protein structure](/ap-bio/frq-practice?id=6983edd9ebf1103b6c5281dc&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Hydrogen bonds stabilizing DNA base pair interactions](/ap-bio/frq-practice?id=6983eec2ebf1103b6c5281e7&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [DNA hydrogen bonding and base pair stability](/ap-bio/frq-practice?id=6983f106ebf1103b6c5281fd&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Peptide bond formation between amino acids](/ap-bio/frq-practice?id=6983f1ecebf1103b6c528206&type=frq-1-interpreting-and-evaluating-experimental-results-long)

### Unit 2: Cells (12)
- [Aquaporins, osmoregulation, and membrane transport](/ap-bio/frq-practice?id=6983e685ebf1103b6c528186&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Osmotic water movement in hypotonic environments](/ap-bio/frq-practice?id=6983e8efebf1103b6c5281a7&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Selective permeability of polar molecule transport](/ap-bio/frq-practice?id=6983e9e7ebf1103b6c5281b0&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Aquaporins and plant drought stress response](/ap-bio/frq-practice?id=6983eacfebf1103b6c5281b9&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Protein sorting and modification within endomembrane system](/ap-bio/frq-practice?id=6983ec7eebf1103b6c5281cc&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Aquaporin-mediated water transport across plasma membranes](/ap-bio/frq-practice?id=6983ed59ebf1103b6c5281d6&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Plant salt tolerance through vacuolar ion sequestration](/ap-bio/frq-practice?id=6983eefcebf1103b6c5281e8&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Water permeability across polar membranes](/ap-bio/frq-practice?id=6983f07cebf1103b6c5281f9&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Water potential and plant tissue osmotic response](/ap-bio/frq-practice?id=6983f16cebf1103b6c528201&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Lysosomal acidification and enzymatic lipid degradation](/ap-bio/frq-practice?id=6983f2a6ebf1103b6c52820d&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Phospholipid bilayer barrier to polar molecules](/ap-bio/frq-practice?id=6983f481ebf1103b6c528225&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Aquaporin protein regulation by cytosolic pH conditions](/ap-bio/frq-practice?id=6983f54cebf1103b6c52822f&type=frq-1-interpreting-and-evaluating-experimental-results-long)

### Unit 3: Cellular Energetics (16)
- [ATP synthesis via electron transport chain](/ap-bio/frq-practice?id=6983e5fbebf1103b6c528180&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Light-dependent reactions, water photolysis, oxygen production](/ap-bio/frq-practice?id=6983e6d6ebf1103b6c52818b&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Carbon fixation and carbohydrate synthesis in photosynthesis](/ap-bio/frq-practice?id=6983e80aebf1103b6c528199&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Compound X effects on mitochondrial ATP synthesis](/ap-bio/frq-practice?id=6983e8c6ebf1103b6c5281a4&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Plant toxin effects on mitochondrial oxygen consumption](/ap-bio/frq-practice?id=6983e9a4ebf1103b6c5281ae&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Light-dependent reactions, proton gradient, ATP synthesis](/ap-bio/frq-practice?id=6983ec8eebf1103b6c5281cd&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Cellular respiration, ATP production, electron transport chain](/ap-bio/frq-practice?id=6983ed63ebf1103b6c5281d7&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Cellular compartmentalization, autophagy, lysosomal protein degradation](/ap-bio/frq-practice?id=6983ee23ebf1103b6c5281dd&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Enzyme active site substrate binding and catalysis](/ap-bio/frq-practice?id=6983ee38ebf1103b6c5281de&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Electron transport chain, oxygen consumption, ATP synthesis](/ap-bio/frq-practice?id=6983f03febf1103b6c5281f6&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Enzyme active site structure and substrate specificity](/ap-bio/frq-practice?id=6983f11eebf1103b6c5281fe&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Electron transport chain energy conversion and proton gradient formation](/ap-bio/frq-practice?id=6983f1f5ebf1103b6c528207&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Amino acid R-group interactions forming protein tertiary structure](/ap-bio/frq-practice?id=6983f2ccebf1103b6c528210&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Light-dependent reactions, electron transport, water oxidation](/ap-bio/frq-practice?id=6983f3c0ebf1103b6c52821a&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Amino acid R-groups, tertiary structure, ionic interactions](/ap-bio/frq-practice?id=6983f50eebf1103b6c52822b&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Oxygen's role in electron transport chain function](/ap-bio/frq-practice?id=6983f578ebf1103b6c528231&type=frq-1-interpreting-and-evaluating-experimental-results-long)

### Unit 4: Cell Communication and Cell Cycle (9)
- [Cyclins and cell cycle regulation mechanisms](/ap-bio/frq-practice?id=69751dee39cb567763bc69c8&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Cell signaling cascade regulating proliferation through phosphorylation](/ap-bio/frq-practice?id=6983e826ebf1103b6c52819c&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Growth factor signaling and cellular proliferation regulation](/ap-bio/frq-practice?id=6983e9c6ebf1103b6c5281af&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Signal transduction through protein kinase phosphorylation cascades](/ap-bio/frq-practice?id=6983eb92ebf1103b6c5281c1&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Growth factor signaling and cell cycle regulation pathways](/ap-bio/frq-practice?id=6983f5c4ebf1103b6c528233&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Cyclin-CDK interaction and cell cycle checkpoint regulation](/ap-bio/frq-practice?id=6983f873ebf1103b6c528254&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Cyclin regulation of cell cycle checkpoints](/ap-bio/frq-practice?id=6983f94cebf1103b6c528260&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Growth Factor Z signaling pathway and cell cycle regulation](/ap-bio/frq-practice?id=6983fa23ebf1103b6c528267&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Signal transduction pathway inhibition and cell division](/ap-bio/frq-practice?id=6983fd05ebf1103b6c528288&type=frq-1-interpreting-and-evaluating-experimental-results-long)

### Unit 5: Heredity (7)
- [Genetic recombination through chromosome exchange during meiosis.](/ap-bio/frq-practice?id=69751de539cb567763bc69c7&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Chromosome pairing and segregation in meiosis](/ap-bio/frq-practice?id=6983e72debf1103b6c52818d&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [HFM1 protein role in meiotic crossover formation](/ap-bio/frq-practice?id=6983ea5aebf1103b6c5281b5&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Genetic recombination and chromosome exchange during meiosis](/ap-bio/frq-practice?id=6983ecfbebf1103b6c5281d4&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Genetic recombination and crossing over in meiosis](/ap-bio/frq-practice?id=6983ee3bebf1103b6c5281df&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Cohesin regulation and chromosome segregation in meiosis](/ap-bio/frq-practice?id=6983f37bebf1103b6c528215&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Meiotic recombination and genetic diversity through crossing over](/ap-bio/frq-practice?id=6983f44bebf1103b6c52821f&type=frq-1-interpreting-and-evaluating-experimental-results-long)

### Unit 6: Gene Expression and Regulation (38)
- [Enzyme active site substrate specificity mechanisms](/ap-bio/frq-practice?id=697438a6af6f894bee0b599a&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [RNA polymerase catalyzes transcription of DNA to mRNA.](/ap-bio/frq-practice?id=69751e0c39cb567763bc69c9&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Amino acid R-groups determine protein tertiary structure](/ap-bio/frq-practice?id=6983e61eebf1103b6c528182&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Cyclin-dependent kinase activation and cell cycle progression control](/ap-bio/frq-practice?id=6983e693ebf1103b6c528187&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Gene expression regulation by microRNA molecules](/ap-bio/frq-practice?id=6983e733ebf1103b6c52818f&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [DNA base pairing and hydrogen bond interactions](/ap-bio/frq-practice?id=6983e7ecebf1103b6c528196&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Lysosomal acidification and macromolecule degradation](/ap-bio/frq-practice?id=6983e82eebf1103b6c52819d&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Cell cycle regulation through growth factor signaling pathway](/ap-bio/frq-practice?id=6983e8feebf1103b6c5281a8&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Flowering time regulation through cold-induced gene silencing](/ap-bio/frq-practice?id=6983ea0febf1103b6c5281b3&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Yeast mating factor signaling pathway and gene regulation](/ap-bio/frq-practice?id=6983eab6ebf1103b6c5281b8&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Gene regulation and transcription factor signaling](/ap-bio/frq-practice?id=6983eaf2ebf1103b6c5281ba&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Genetic recombination through homologous chromosome exchange](/ap-bio/frq-practice?id=6983eb42ebf1103b6c5281be&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Hydrophobic lipid bilayer excludes ionic solutes](/ap-bio/frq-practice?id=6983eba8ebf1103b6c5281c2&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Transcription factor regulation of gene expression](/ap-bio/frq-practice?id=6983ebc8ebf1103b6c5281c4&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Phosphate nutrient availability regulates transporter gene expression](/ap-bio/frq-practice?id=6983ec9eebf1103b6c5281cf&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Gene expression regulation under hypoxic conditions](/ap-bio/frq-practice?id=6983ed84ebf1103b6c5281d9&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Gene regulation and heat shock protein expression](/ap-bio/frq-practice?id=6983ee5aebf1103b6c5281e2&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Protein synthesis, modification, and lysosomal targeting](/ap-bio/frq-practice?id=6983efc1ebf1103b6c5281f0&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Gene expression regulation during drought stress response](/ap-bio/frq-practice?id=6983f016ebf1103b6c5281f5&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Iron homeostasis regulation through post-transcriptional control](/ap-bio/frq-practice?id=6983f0fdebf1103b6c5281fc&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Heat shock proteins and cellular stress response regulation](/ap-bio/frq-practice?id=6983f229ebf1103b6c528209&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Crossing over mechanisms and chromosomal recombination during meiosis](/ap-bio/frq-practice?id=6983f29febf1103b6c52820c&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Enzyme catalysis and pyruvate dehydrogenase inhibition](/ap-bio/frq-practice?id=6983f2c3ebf1103b6c52820f&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Gene expression regulation through alternative splicing mechanisms](/ap-bio/frq-practice?id=6983f379ebf1103b6c528214&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Amino acid R-groups and protein tertiary structure](/ap-bio/frq-practice?id=6983f431ebf1103b6c52821c&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Heat shock response and HSP gene regulation](/ap-bio/frq-practice?id=6983f44debf1103b6c528220&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Cohesin protein protection during meiosis I](/ap-bio/frq-practice?id=6983f50bebf1103b6c52822a&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Osmotic stress response through gene regulation pathway](/ap-bio/frq-practice?id=6983f539ebf1103b6c52822d&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Hydrogen bonds in protein secondary structure formation](/ap-bio/frq-practice?id=6983f5ffebf1103b6c528235&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Bacterial quorum sensing and biofilm formation regulation](/ap-bio/frq-practice?id=6983f617ebf1103b6c528236&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Aquaporin function in plant water transport](/ap-bio/frq-practice?id=6983f623ebf1103b6c528237&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Growth factor signaling and cell cycle regulation pathways](/ap-bio/frq-practice?id=6983f68aebf1103b6c52823e&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Gene expression regulation in yeast metabolic adaptation](/ap-bio/frq-practice?id=6983f6f2ebf1103b6c528243&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Amino acid R-groups and protein tertiary structure](/ap-bio/frq-practice?id=6983f748ebf1103b6c528248&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Growth factor signaling cascade and kinase phosphorylation](/ap-bio/frq-practice?id=6983f785ebf1103b6c52824a&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Gene expression regulation through phosphate availability](/ap-bio/frq-practice?id=6983f7ecebf1103b6c528250&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Amino acid R groups and protein tertiary structure](/ap-bio/frq-practice?id=6983f882ebf1103b6c528255&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Cell cycle regulation through growth factor signaling](/ap-bio/frq-practice?id=6983fc38ebf1103b6c52827f&type=frq-1-interpreting-and-evaluating-experimental-results-long)

### Unit 7: Natural Selection (19)
- [Krebs cycle's role in energy production](/ap-bio/frq-practice?id=69751dc539cb567763bc69c5&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Conditions enabling evolution through genetic variation](/ap-bio/frq-practice?id=69751ede39cb567763bc69d4&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Phenotypic variation, predation, environmental adaptation fitness](/ap-bio/frq-practice?id=6983e818ebf1103b6c52819b&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Pesticide resistance evolution in mosquito populations](/ap-bio/frq-practice?id=6983e8efebf1103b6c5281a6&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Heavy metal tolerance evolution in plant populations](/ap-bio/frq-practice?id=6983ebccebf1103b6c5281c6&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Herbicide resistance evolution through natural selection](/ap-bio/frq-practice?id=6983eccdebf1103b6c5281d2&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Pesticide resistance evolution in beetle populations](/ap-bio/frq-practice?id=6983eea2ebf1103b6c5281e5&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Homologous chromosome pairing and genetic material exchange](/ap-bio/frq-practice?id=6983f0ccebf1103b6c5281fa&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Herbicide resistance evolution in weed populations](/ap-bio/frq-practice?id=6983f0f5ebf1103b6c5281fb&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Genetic recombination through crossing over during meiosis](/ap-bio/frq-practice?id=6983f180ebf1103b6c528203&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Herbicide resistance through gene amplification mechanisms](/ap-bio/frq-practice?id=6983f1ceebf1103b6c528205&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Beak depth evolution in finch populations through environmental selection](/ap-bio/frq-practice?id=6983f29febf1103b6c52820b&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Bacterial antibiotic resistance through genetic mutations](/ap-bio/frq-practice?id=6983f458ebf1103b6c528221&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Enzyme catalysis and substrate concentration effects](/ap-bio/frq-practice?id=6983f49febf1103b6c528226&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Antibiotic resistance evolution through natural selection](/ap-bio/frq-practice?id=6983f55debf1103b6c528230&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Antibiotic resistance evolution through natural selection](/ap-bio/frq-practice?id=6983f642ebf1103b6c528239&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Lactase persistence evolution in human populations](/ap-bio/frq-practice?id=6983f743ebf1103b6c528247&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Camouflage, predation, and phenotypic variation selection](/ap-bio/frq-practice?id=6983f80febf1103b6c528251&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Genetic variation and antibiotic resistance in bacteria](/ap-bio/frq-practice?id=6983f9d1ebf1103b6c528263&type=frq-1-interpreting-and-evaluating-experimental-results-long)

### Unit 8: Ecology (19)
- [Matter cycling through decomposition in ecosystems](/ap-bio/frq-practice?id=69751ed139cb567763bc69d3&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Mycorrhizal fungi, allelopathy, plant-microbe interactions](/ap-bio/frq-practice?id=6983e95aebf1103b6c5281ab&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Trophic levels, energy flow, predator-prey interactions](/ap-bio/frq-practice?id=6983ea35ebf1103b6c5281b4&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Energy flow from producers to consumers through trophic levels](/ap-bio/frq-practice?id=6983eaf9ebf1103b6c5281bc&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Kelp forest trophic dynamics and predator effects](/ap-bio/frq-practice?id=6983ebccebf1103b6c5281c5&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Nutrient pollution effects on freshwater algal biomass](/ap-bio/frq-practice?id=6983eca7ebf1103b6c5281d0&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Photosynthesis and cellular respiration in plant growth](/ap-bio/frq-practice?id=6983ed6debf1103b6c5281d8&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Water temperature effects on zooplankton metabolic rates](/ap-bio/frq-practice?id=6983ee59ebf1103b6c5281e1&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Nitrogen cycling and decomposer roles in ecosystems](/ap-bio/frq-practice?id=6983ef60ebf1103b6c5281ed&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Trophic cascades, invasive species, energy flow](/ap-bio/frq-practice?id=6983f041ebf1103b6c5281f7&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Trophic cascades and energy flow in aquatic food webs](/ap-bio/frq-practice?id=6983f12cebf1103b6c5281ff&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Invasive species disrupting mycorrhizal fungal relationships](/ap-bio/frq-practice?id=6983f204ebf1103b6c528208&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Carbon cycling in aquatic producer ecosystems](/ap-bio/frq-practice?id=6983f2bbebf1103b6c52820e&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Enzyme activity and temperature in ectothermic organisms](/ap-bio/frq-practice?id=6983f3acebf1103b6c528218&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Invasive species competition with native plants](/ap-bio/frq-practice?id=6983f46debf1103b6c528223&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Salt marsh ecosystem biomass regulation mechanisms](/ap-bio/frq-practice?id=6983f548ebf1103b6c52822e&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Nutrient pollution impacts freshwater ecosystem biodiversity](/ap-bio/frq-practice?id=6983f6fbebf1103b6c528244&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Invasive lionfish predation on native reef fish recruitment](/ap-bio/frq-practice?id=6983f7d0ebf1103b6c52824e&type=frq-1-interpreting-and-evaluating-experimental-results-long)
- [Invasive species competition in freshwater ecosystems](/ap-bio/frq-practice?id=6983f886ebf1103b6c528256&type=frq-1-interpreting-and-evaluating-experimental-results-long)

## Sample question

**Amino acid R-groups determine protein tertiary structure**

Proteins are essential macromolecules that perform a diverse range of functions in living organisms, including catalyzing metabolic reactions. The function of a protein is directly determined by its specific three-dimensional shape, which is established by interactions between its constituent amino acids.

Researchers are investigating the enzyme dihydrofolate reductase (DHFR) in a species of bacteria, Thermophilus aquaticus, which lives in hot springs, and a related species, Escherichia coli, which lives in the mammalian gut. DHFR is an enzyme critical for DNA synthesis. The researchers purified DHFR from both species to study their thermal stability.

They incubated the purified enzymes from both species at temperatures ranging from 30°C to 90°C for 10 minutes. After incubation, they cooled the samples to 37°C and measured the remaining enzyme activity by adding substrate and monitoring product formation. The activity was calculated as a percentage relative to the activity of the enzyme kept at 37°C (Figure 1).

To understand the molecular basis for the difference in thermal stability, the researchers analyzed the protein structures. They focused on a specific region of the protein surface where the amino acid sequence differed between the two species. Figure 2 shows a simplified model of the interactions between amino acid side chains in this region for both the E. coli and T. aquaticus enzymes.

Part A (1 point):
  Prompt: **Describe** how the R-groups of amino acids contribute to the tertiary structure of a protein.
  Verb: describe

Figure 1:
  Type: graph
  Caption: Figure 1. Effect of 10-minute incubation temperature on DHFR activity. Relative enzyme activity is measured at 37°C after cooling and is expressed as a percent of the 37°C control for each species. Error bars show ±SE.
  URL: https://kcbwzropdukwhmmvdylp.supabase.co/storage/v1/object/public/frq_stimulus/ap-bio/b4c97c28-889d-4eec-83ed-f541c291bbb8_fig1.jpg
  Placement: before-part
  Part Letter: B

Part B (3 points):
  i. **Identify** the independent variable in the experiment shown in Figure 1. (1 pt)
    Verb: identify
  ii. **Justify** the researchers' decision to cool the enzyme samples to 37°C before measuring their activity, rather than measuring activity at the incubation temperatures. (1 pt)
    Verb: justify
  iii. Based on Figure 1, **describe** the effect of increasing temperature from 40°C to 60°C on the activity of the E. coli enzyme. (1 pt)
    Verb: describe

Figure 2:
  Type: diagram
  Caption: Figure 2. Amino acid side-chain interactions in a structural domain of DHFR from E. coli versus T. aquaticus. Panel A shows nonionic hydrophobic side chains without an inter-side-chain bond; Panel B shows an ionic interaction (salt bridge) between oppositely charged side chains.
  URL: https://kcbwzropdukwhmmvdylp.supabase.co/storage/v1/object/public/frq_stimulus/ap-bio/b4c97c28-889d-4eec-83ed-f541c291bbb8_fig2.jpg
  Placement: before-part
  Part Letter: C

Part C (3 points):
  i. Based on Figure 2, **identify** the specific type of chemical interaction present in the T. aquaticus enzyme that is absent in the E. coli enzyme. (1 pt)
    Verb: identify
  ii. **Identify** the level of protein structure (primary, secondary, tertiary, or quaternary) that is stabilized by the interaction between the side chains of Glutamic Acid and Lysine shown in Figure 2. (1 pt)
    Verb: identify
  iii. The molecular mass of the amino acid Glutamic Acid is 147 Daltons, and the molecular mass of Valine is 117 Daltons. Calculate the difference in mass (in Daltons) of the protein if a single Glutamic Acid residue is substituted with a Valine residue. (1 pt)
    Verb: calculate

Part D (2 points):
  i. Researchers claim that the T. aquaticus enzyme is evolutionarily adapted to function in high-temperature environments. Using data from Figure 1, **support** the researchers' claim. (1 pt)
    Verb: support
  ii. Researchers claim that replacing the Glutamic Acid in the T. aquaticus enzyme with Valine would decrease the thermal stability of the enzyme. **Justify** the researchers' claim based on the information in Figure 2 and your understanding of protein structure. (1 pt)
    Verb: justify

Image URLs (2):
  - https://kcbwzropdukwhmmvdylp.supabase.co/storage/v1/object/public/frq_stimulus/ap-bio/b4c97c28-889d-4eec-83ed-f541c291bbb8_fig1.jpg
  - https://kcbwzropdukwhmmvdylp.supabase.co/storage/v1/object/public/frq_stimulus/ap-bio/b4c97c28-889d-4eec-83ed-f541c291bbb8_fig2.jpg

## Questions

**How many responses can I get scored?**

You can read every question without a plan. Your first scored response is included. A plan unlocks unlimited scoring.

**How is FRQ 1 different from FRQ 2?**

Both give you an experiment with data and the same four parts. FRQ 1 gives you figures to read. FRQ 2 asks you to build a graph from a data table.

**How do I show a calculation?**

Type your setup, the numbers, and the answer with its units. You can also switch the editor to handwrite, write on paper, and add a photo of your page.

**Do I have to write in complete sentences?**

Yes. On the exam, outlines and bulleted lists alone aren’t scored, so write each part in full sentences.

**Are these real College Board questions?**

No. We wrote them in the AP format, with the same four parts, and wrote scoring guidelines for each one.

## Related

- [Experimental Results FRQ exam guide](/ap-bio/ap-biology-exam/ap-bio-frq-long/study-guide/ap-bio-frq-long)
- [AP Biology Graphing FRQ practice](/ap-bio/frqs/graphing)
- [AP Biology Scientific Investigation FRQ practice](/ap-bio/frqs/scientific-investigation)
- [AP Biology Conceptual Analysis FRQ practice](/ap-bio/frqs/conceptual-analysis)
- [AP Biology Model Analysis FRQ practice](/ap-bio/frqs/model-analysis)
- [AP Biology Data Analysis FRQ practice](/ap-bio/frqs/data-analysis)
- [AP Biology FRQs](/ap-bio/frqs)
- Any question by id: the `get_frq` tool on the [Fiveable MCP server](/mcp/docs)

## About This Document

Canonical Fiveable pages are available as Markdown at the same path plus `.md`.

- [llms.txt](https://fiveable.me/llms.txt): index of Fiveable's sections and URL patterns
- [llms-full.txt](https://fiveable.me/llms-full.txt): complete subject and unit listing
- [MCP server](https://fiveable.me/mcp): call Fiveable as tools instead of fetching pages (`https://fiveable.me/api/mcp`)
- [MCP server for AP teachers](https://fiveable.me/mcp/teachers): a teacher's classes, assignments and AP-rubric grading (`https://fiveable.me/api/mcp/teacher`)