AP Biology Lab InvestigationsThe 13 Required Labs

The 13 required AP Biology lab investigations

1. 1

   Artificial Selection

   EVO

   Students select for a trait in a fast growing organism such as Wisconsin Fast Plants across generations, choosing which individuals reproduce and tracking how the trait distribution shifts. It makes the mechanism of selection concrete: heritable variation plus differential reproduction changes allele frequencies over time. The investigation builds skill in quantifying a trait, comparing parent and offspring distributions, and arguing from data that selection, not chance, produced the change.

   On the exam: Appears as evolution prompts asking students to predict and justify how selection changes a population over generations.

2. 2

   Mathematical Modeling: Hardy-Weinberg

   EVO

   Students build a spreadsheet or physical model of allele frequencies and test how selection, mutation, migration and population size move a population away from Hardy Weinberg equilibrium. The lab connects the algebra (p squared plus 2pq plus q squared) to a real population process and shows that equilibrium is a null model: deviation is the evidence that evolution is occurring. Key skills are calculating allele and genotype frequencies and interpreting what a departure from equilibrium implies.

   On the exam: Hardy Weinberg calculation and interpretation is among the highest yield quantitative skills on the exam.

3. 3

   Comparing DNA Sequences with BLAST

   EVO

   Students use the BLAST database tool to compare gene or protein sequences across species and build a cladogram from sequence similarity. It demonstrates that molecular data is evidence for common ancestry and that more shared sequence implies more recent divergence. The investigation builds skill in reading phylogenetic trees, interpreting sequence alignment data, and constructing an evidence based evolutionary argument.

   On the exam: Supports phylogeny and common ancestry questions that ask students to interpret molecular evidence and trees.

4. 4

   Diffusion and Osmosis

   ENE/SYI

   Using dialysis tubing and potato or plant tissue in solutions of varying solute concentration, students measure mass change to quantify water movement and estimate solute potential and water potential. It grounds tonicity, hypotonic and hypertonic environments, and the water potential equation in measurable data. Core skills are calculating percent change in mass, plotting it against concentration, and using water potential to predict the direction of water movement.

   On the exam: Tonicity, osmoregulation and water potential are perennial data analysis FRQ contexts.

5. 5

   Photosynthesis

   ENE

   Students measure photosynthetic rate, commonly with the floating leaf disk technique, while varying light intensity, light color, or carbon dioxide availability. It makes the light dependent reactions and the factors limiting photosynthesis measurable rather than memorized. The investigation builds skill in defining a rate, designing a controlled comparison, and explaining why a limiting factor changes the rate.

   On the exam: Photosynthesis is a heavy Unit 3 topic and a frequent experimental FRQ scenario.

6. 6

   Cellular Respiration

   ENE

   Students use a respirometer to measure oxygen consumption in germinating versus dormant seeds or in organisms at different temperatures. It connects aerobic respiration to a measurable variable and shows how temperature and metabolic state change respiration rate. Key skills are controlling for gas volume and temperature, calculating a rate from volume change over time, and justifying the effect of a variable on metabolism.

   On the exam: Respiration, including the role of the inner mitochondrial membrane, is a recurring Chief Reader error zone.

7. 7

   Cell Division: Mitosis and Meiosis

   IST

   Students score chromosome behavior and the proportion of cells in each phase, and model crossing over and independent assortment with chromosome simulations or fungal crosses. It makes the sources of genetic variation concrete and corrects the common belief that crossing over replaces genes or causes mutation. Core skills are calculating phase proportions and the mitotic index and reasoning about how meiosis generates diversity.

   On the exam: Underpins heredity FRQs on the sources of genetic variation, a documented misconception area.

8. 8

   Biotechnology: Bacterial Transformation

   IST

   Students transform E. coli with a plasmid carrying a selectable marker such as antibiotic resistance and a reporter gene, then calculate transformation efficiency from colony counts. It demonstrates that genes can move between organisms and be expressed, and connects plasmids, selection and gene expression. The key quantitative skill is computing transformation efficiency and interpreting plates with appropriate controls.

   On the exam: Supports gene expression and biotechnology questions and experimental design with controls.

9. 9

   Biotechnology: Restriction Enzyme Analysis of DNA

   IST

   Students cut DNA with restriction enzymes and separate fragments by gel electrophoresis, then estimate fragment sizes against a standard ladder. It shows how sequence specific cutting plus size separation reveals DNA structure and is the basis of DNA fingerprinting. Core skills are reading a gel, building and using a standard curve to estimate fragment size, and interpreting banding patterns.

   On the exam: Appears in molecular genetics questions requiring interpretation of gels and standard curves.

10. 10

    Energy Dynamics

    ENE/SYI

    Students measure biomass and energy flow through a simple producer to consumer system, often using Wisconsin Fast Plants and cabbage white butterfly larvae, to quantify productivity and trophic efficiency. It connects energy capture, the roughly ten percent rule of energy transfer, and ecosystem productivity to measured data. Key skills are calculating productivity and energy transfer efficiency and explaining energy loss between trophic levels.

    On the exam: Supports Unit 8 energy flow questions and quantitative ecosystem reasoning.

11. 11

    Transpiration

    ENE/SYI

    Using a potometer, students measure water uptake by a plant cutting while varying humidity, wind, or light, and relate it to stomatal function and water potential. It connects transpiration, the cohesion tension mechanism, and environmental control of water loss to a measurable rate. Core skills are calculating transpiration rate, normalizing to leaf surface area, and predicting the effect of an environmental variable.

    On the exam: A classic experimental FRQ context for variables, controls, and rate calculation.

12. 12

    Fruit Fly Behavior

    SYI

    Students design a choice chamber experiment to test how Drosophila respond to environmental stimuli such as light, food odor, or pH, recording where organisms accumulate over time. It builds the full inquiry cycle: posing a testable question, designing controls, collecting behavioral data, and applying a chi square test to evaluate whether a response differs from chance. The statistical analysis is the central transferable skill.

    On the exam: Directly supports experimental design and chi square FRQs, both high frequency skills.

13. 13

    Enzyme Activity

    ENE

    Students measure the rate of an enzyme catalyzed reaction, often peroxidase or catalase, while varying temperature, pH, or substrate concentration. It makes enzyme structure and function, denaturation, and the effect of conditions on reaction rate measurable. Core skills are defining and calculating a reaction rate, identifying independent and dependent variables, and explaining why a condition changes activity for enzyme structure.

    On the exam: Enzyme function under changing conditions is a recurring Unit 3 experimental scenario.

These 13 inquiry based investigations form College Board's recommended AP Biology lab program (AP Biology Investigative Labs: An Inquiry Based Approach). Teachers may select fewer as long as the course meets the lab and Big Idea coverage expectations.