Figure 1 models the folding of Protein X, a cytosolic protein found in animal cells.
A.
Describe the chemical property of the amino acids in Region A that results in their location within the folded protein.
Figure 1. Structural features of Protein X
B.
Based on Figure 1, explain why the amino acids in Region A cluster together in the center of the protein rather than interacting with the surrounding cytosol.
C.
Using the information in Figure 1, identify the level of protein structure represented by Interaction B: secondary structure, tertiary structure, or quaternary structure.
D.
Based on Figure 1, explain how a significant decrease in pH would affect Interaction B in such a way that Protein X loses its function.
What the Model Analysis FRQ asks
This is FRQ 5 on the AP Biology exam. You get a diagram, model, or other visual and answer four parts that describe it, explain how its pieces relate, and connect it to a larger biological principle.
Connect the model to a larger biological principle
1 pt
How Model Analysis FRQ practice works
Each question follows the exam’s format, from the full prompt to a score on every part.
1
Read the full question
The visual and all four parts, A through D, laid out the way the exam shows them.
2
Write on a 10-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 4
Your response is scored against the scoring guidelines written for that question. Your first score is included.
Feedback on every part
A summary at the top tells you what to work on next. Below it, each part shows whether you earned the point and what the scoring guidelines were looking for.
The student correctly identifies photosynthesis and describes the conversion of inorganic CO₂ into organic molecules such as glucose. This meets the requirement of connecting photosynthesis to the conversion of inorganic carbon to organic carbon, earning the point.
Part B: 0/1 point
The student correctly identifies that soil microbes release CO₂ through cellular respiration, but fails to complete the causal chain by explaining how the increased atmospheric CO₂ traps heat (greenhouse effect) to raise global temperature. Simply stating that CO₂ 'contributes to the rise in global temperature' without explaining the heat-trapping mechanism does not satisfy the requirement for both parts of the causal chain.
Part D: 1/1 point
The student correctly explains that increased global temperature causes more permafrost to thaw (mechanism) and that this would decrease the size of the Permafrost Soil Carbon reservoir over time (direction of change). Both required components are present, earning the point.
Detailed feedback on a practice Model Analysis FRQ
Questions about the Model Analysis FRQ
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.
What kinds of visuals show up?
Diagrams of cell structures, metabolic pathways, phylogenetic trees, and other models of biological systems.
How is this different from the Data Analysis FRQ?
This question asks you to read a model or diagram. The Data Analysis FRQ gives you a graph or table of results to describe and evaluate.
How long should each part be?
Two to four focused sentences usually does it. Each part is worth 1 point, so answer every part.
More AP Biology practice
Experimental Results FRQ practice
Long FRQs with a research scenario, its figures, and all four parts.
