Best examples of methods section examples for biology lab reports

Short, strong example of methods section for an enzyme activity lab

Let’s start with a compact example of methods section writing for a classic enzyme catalase lab. This is the kind of paragraph you might see in an A-level undergraduate report.

Example of enzyme activity methods section
Catalase activity was measured in fresh Solanum tuberosum (potato) tissue at three temperatures: 4 °C, 22 °C, and 37 °C. Potato cylinders (5 mm diameter, 10 mm length) were cut using a cork borer and standardized with a metric ruler. All samples were prepared from the same potato to reduce variability. For each temperature condition, three replicate cylinders were incubated in 10 mL of 3% (v/v) hydrogen peroxide solution in 50 mL glass beakers. Beakers were maintained at the target temperature using an ice bath (4 °C), room temperature bench (22 °C), or water bath (37 °C). The time required to produce a 2 cm foam column was recorded using a digital stopwatch (±0.01 s). Between trials, beakers were rinsed with distilled water and fresh peroxide solution was used. Data were recorded in a lab notebook and later entered into a spreadsheet for analysis.

Why this works: it’s specific, uses consistent units, identifies replicates, and someone at another college could realistically repeat it.

Longer examples of methods section examples for biology lab reports (core undergraduate labs)

The best examples of methods section examples for biology lab reports do more than list steps. They:

• Explain how samples were selected or assigned to conditions
• Describe controls and replicates
• Specify instruments, software, and statistical tests
• Mention safety and ethical considerations when relevant

Here are several real-style examples, each modeled on labs widely used in U.S. biology courses.

Example 1: Osmosis in plant cells (potato cores)

Osmosis methods section example
Osmosis was investigated in potato tuber tissue exposed to sucrose solutions of varying molarity. A single Russet potato was peeled and cored using a 5 mm diameter cork borer. Cores were cut to a length of 30 mm and blotted dry with paper towels. Initial mass of each core was measured using a digital balance (±0.01 g). Sucrose solutions (0.0, 0.2, 0.4, 0.6, and 0.8 M) were prepared using distilled water and analytical-grade sucrose. For each concentration, five potato cores were placed in 100 mL of solution in labeled 250 mL beakers, providing five biological replicates per treatment. Beakers were covered with Parafilm to reduce evaporation and left at room temperature (22 ± 1 °C) for 60 minutes. After incubation, cores were removed, gently blotted dry, and reweighed. Percent change in mass was calculated for each core. All procedures followed general lab safety guidelines for chemical handling as outlined by the institution’s safety office.

This is a clean example of methods section writing that shows sample size, solution prep, and timing—exactly what graders look for.

Example 2: Bacterial growth and antibiotic sensitivity (Kirby–Bauer)

Microbiology methods section example
The effect of three antibiotics on Escherichia coli growth was evaluated using a Kirby–Bauer disk diffusion assay, following general principles similar to those recommended by the Clinical and Laboratory Standards Institute. A single colony of E. coli K-12 was transferred to 5 mL of sterile nutrient broth and incubated at 37 °C with shaking at 150 rpm for 18 hours. The overnight culture was diluted with sterile saline to match a 0.5 McFarland turbidity standard. Mueller–Hinton agar plates were inoculated by evenly spreading 100 µL of the standardized bacterial suspension using a sterile cotton swab. Sterile paper disks impregnated with ampicillin (10 µg), tetracycline (30 µg), or ciprofloxacin (5 µg) were placed on the agar surface using sterile forceps. Plates were incubated inverted at 37 °C for 24 hours. Zones of inhibition were measured with a digital caliper (±0.1 mm). All work with live cultures was conducted in a biosafety cabinet following Biosafety Level 1 guidelines from the Centers for Disease Control and Prevention (CDC).

Note how this example of a methods section brings in safety levels and external standards, which many instructors now expect. For more on biosafety practices, students often reference CDC biosafety guidance.

Example 3: Enzyme kinetics with spectrophotometry

Enzyme kinetics methods section example
The effect of substrate concentration on alkaline phosphatase activity was quantified using a spectrophotometric assay. Alkaline phosphatase from bovine intestinal mucosa (Sigma-Aldrich) was prepared at 0.5 U/mL in 50 mM glycine buffer, pH 10.4. p-Nitrophenyl phosphate (pNPP) was used as the substrate at final concentrations of 0.5, 1, 2, 4, and 8 mM. Reactions were initiated by adding 100 µL of enzyme solution to 900 µL of pre-warmed substrate solution in 1.5 mL cuvettes, yielding a total volume of 1.0 mL. Absorbance at 405 nm was recorded every 30 seconds for 5 minutes using a UV–Vis spectrophotometer (Bio-Rad, model xxxxx) at 25 °C. Three independent reactions were run for each substrate concentration. Initial reaction rates were calculated from the linear portion of the absorbance versus time curve and converted to µmol/min using a standard curve of p-nitrophenol. Data were analyzed using non-linear regression in GraphPad Prism (version xx) to estimate Vmax and Km.

This is one of the best examples of methods section style for upper-division labs: note the software, model, and how rates are calculated.

Example 4: Drosophila genetics cross

Genetics methods section example
A monohybrid cross was performed in Drosophila melanogaster to analyze inheritance of the white eye mutation. Virgin female flies with the white-eye phenotype (w/w) were collected within 8 hours of eclosion using CO₂ anesthesia. These females were crossed with red-eyed wild-type males (+/+). Ten females and ten males were transferred to each of three replicate culture vials containing standard cornmeal–agar medium. Flies were allowed to mate and lay eggs for 7 days at 25 °C under a 12:12 light:dark cycle, after which adults were removed. F₁ offspring were allowed to develop and eclose under the same conditions. Adult F₁ flies were anesthetized with CO₂, sexed under a stereomicroscope, and scored for eye color. All flies were handled in accordance with institutional guidelines for humane treatment of invertebrates.

This genetics example of a methods section shows how to handle living organisms and replicate vials without turning the section into a narrative.

Example 5: Photosynthesis and light intensity (chlorophyll fluorescence)

Plant physiology methods section example
The relationship between light intensity and photosynthetic performance was assessed in Arabidopsis thaliana using chlorophyll fluorescence. Four-week-old plants grown under controlled conditions (22 °C, 60% relative humidity, 16:8 light:dark cycle at 150 µmol photons m⁻² s⁻¹) were dark-adapted for 30 minutes. Maximum quantum yield of photosystem II (Fv/Fm) and light response curves were measured using a pulse-amplitude modulated (PAM) fluorometer (Walz MINI-PAM). For each plant, actinic light was applied in a stepwise manner (0, 50, 100, 200, 400, and 800 µmol photons m⁻² s⁻¹), with 3-minute equilibration at each intensity. Three leaves per plant and five plants per treatment were measured, providing 15 technical measurements per light level. Fluorescence parameters were calculated using the manufacturer’s software. Environmental conditions during measurement were kept constant at 22 ± 1 °C.

This is a realistic example of methods section language for ecology/plant physiology courses that use modern equipment.

Example 6: Human physiology – heart rate and exercise

Human physiology methods section example
The effect of moderate exercise on heart rate was measured in healthy adult volunteers (n = 12; 6 female, 6 male; age 18–24 years). Participation was voluntary and followed institutional guidelines for student research with human participants. Resting heart rate was recorded after subjects sat quietly for 5 minutes. Heart rate was measured using a validated wrist-worn heart rate monitor (Polar model xxxx) that had been calibrated according to the manufacturer’s instructions. Subjects then performed 5 minutes of step exercise on a 12-inch step at a rate of 24 steps per minute, guided by a metronome. Heart rate was recorded immediately after exercise and again 5 minutes post-exercise. Data were anonymized and entered into a password-protected spreadsheet for analysis.

This shows how to include ethical and privacy language, which is increasingly expected in 2024–2025, especially in labs involving humans. Many instructors reference human subjects guidance from sources like NIH when designing these labs.

How to model your writing on the best examples of methods sections

Reading examples of methods section examples for biology lab reports is only useful if you know what to copy in terms of structure and what to leave out.

Notice how the real examples above:

• Use past tense and third person: “was measured,” “were incubated,” not “I measured.”
• Avoid bullet-point protocols. Instead, they turn procedures into coherent paragraphs.
• Group related information: sample prep in one chunk, incubation conditions in another, measurement and analysis in a third.
• Provide enough detail to repeat the experiment, but don’t rewrite the entire lab manual.

If you’re adapting these examples of methods section examples for biology lab reports, think in terms of short, focused paragraphs:

• One paragraph for organisms or materials (species, strain, source, preparation).
• One paragraph for experimental setup and treatments (concentrations, temperatures, durations, controls).
• One paragraph for measurements and analysis (instruments, wavelengths, software, statistics).

You’re not trying to impress with fancy vocabulary. You’re trying to make it impossible for a careful reader to misunderstand what you did.

Updated 2024–2025 expectations: what instructors now look for

Biology lab teaching has shifted a bit in the last few years. When instructors grade the methods section in 2024–2025, they often look for elements that older examples didn’t emphasize.

From comparing current syllabi and lab manuals across U.S. universities, the best examples of methods section examples for biology lab reports now usually include:

Reproducibility details
Students are expected to specify:

• Exact sample sizes (n values) and number of replicates
• Key brands or models when they matter (e.g., spectrophotometer, PCR machine)
• Statistical tests used (even briefly, if you don’t explain them until the Results)

Ethics and safety
Especially for labs involving humans, animals, or microbes, students are encouraged to mention:

• That procedures followed institutional or instructor guidelines
• That data were anonymized or de-identified, when appropriate
• That work with microbes followed Biosafety Level guidance (see CDC lab safety)

Digital tools and analysis software
In 2024–2025, more labs incorporate data analysis tools like R, Excel, SPSS, or GraphPad Prism. Strong examples include a short note, such as:

Data were analyzed using R (version 4.x) with two-sample t-tests to compare treatment means.

You don’t have to turn the methods into a statistics lecture, but acknowledging your analysis tool and test is standard practice.

Turning a lab handout into your own methods section

Most students start from a step-by-step lab handout. The trap is copying it word-for-word. Instructors recognize that instantly.

Here’s how to use these examples of methods section examples for biology lab reports to rewrite a handout in your own voice:

1. Combine steps into sentences
If your handout says:

• Label 5 test tubes A–E.
• Add 5 mL of 0.2 M sucrose to tube A.
• Add 5 mL of 0.4 M sucrose to tube B.

You might write:

Five test tubes were labeled A–E and filled with 5 mL of sucrose solutions at 0.2, 0.4, 0.6, 0.8, and 1.0 M, respectively.

2. Generalize repetitive steps
Instead of describing every identical replicate separately, say:

Each treatment was replicated three times, for a total of 15 experimental units.

3. Keep the logic, skip the “you”
Handouts say “You will measure…”; methods sections say “Heart rate was measured…”

Look back at the real examples of methods section examples for biology lab reports above. None of them sound like instructions. They sound like a record of what was done.

FAQ: common questions about methods section examples for biology lab reports

How long should the methods section be in a typical biology lab report?
For an introductory college lab, the methods section is often one to three well-developed paragraphs, sometimes a page if the experiment is complex. The best examples of methods section writing are long enough to be repeatable, but short enough to avoid narrating every minor action.

Can I use bullet points, or should I copy these prose examples of methods sections?
Most instructors prefer prose. Bullet points feel like a protocol, not a scientific report. Use the examples of methods section examples for biology lab reports here as a guide: complete sentences, organized into logical paragraphs.

Do I need to mention brand names and catalog numbers?
Only if they affect the outcome or your instructor asks for them. In the real examples above, brand names are included for specialized equipment (like PAM fluorometers or heart rate monitors), but not for basic items like beakers. If in doubt, check your lab manual or course rubric.

Is it acceptable to copy an example of a methods section from a friend or online?
No. You can study examples of methods section examples for biology lab reports to learn structure and wording, but your text must describe your experiment, your conditions, and your data. Copying text is usually treated as plagiarism, even if the experiment is the same.

Should I cite external sources in the methods section?
Sometimes. If you followed a published protocol or a standardized method (for example, a CDC or NIH protocol), it’s reasonable to mention it briefly and include a reference in your bibliography. For background or conceptual information, save most citations for the Introduction and Discussion. For general research skills and scientific writing advice, many students use university writing centers, such as Harvard’s Writing Center, as a reference.

The bottom line: read and adapt, don’t copy. Use these real-style examples of methods section examples for biology lab reports as models for tone, structure, and level of detail. Then rewrite your own procedures so a stranger could repeat your experiment without ever seeing your lab handout.