Best examples of citing sources in biology lab reports

Real examples of citing sources in biology lab reports

Let’s start with what you actually came for: concrete examples of citing sources in biology lab reports that look like something a strong undergraduate or early grad student would write.

Imagine you’re writing a lab report on enzyme activity in catalase extracted from potato tissue. Here are several in-text citation examples in APA style, exactly how they might appear in your Introduction and Discussion sections:

Previous work has shown that catalase activity increases with temperature up to an organism-specific optimum, beyond which denaturation occurs (Nelson & Cox, 2021).

In mammals, catalase is highly expressed in liver and red blood cells, where it protects cells from hydrogen peroxide–induced damage (National Institutes of Health, 2023).

Our protocol for measuring catalase activity was adapted from the standard spectrophotometric method described in the BIOL 201 laboratory manual (Smith, 2024).

Right there you already have three realistic examples of citing sources in biology lab reports: a textbook, a government website, and a lab manual. Notice the pattern: idea or fact first, citation immediately after, before the period.

Examples of in-text citations in biology lab reports (APA, CSE, MLA)

Different biology courses use different citation styles. Many U.S. biology departments prefer CSE (Council of Science Editors), while others stick with APA. Some general education labs still use MLA. The best examples of citing sources in biology lab reports show you how the same sentence looks in each style.

Take this sentence about E. coli growth:

APA style example

E. coli grows optimally at 37 °C in rich media such as Luria–Bertani broth (Madigan et al., 2021).

CSE Name–Year style example

E. coli grows optimally at 37 °C in rich media such as Luria–Bertani broth (Madigan et al. 2021).

CSE Citation–Sequence style example

E. coli grows optimally at 37 °C in rich media such as Luria–Bertani broth (1).

MLA style example

E. coli grows optimally at 37 °C in rich media such as Luria–Bertani broth (Madigan et al. 45).

These side‑by‑side examples of citing sources in biology lab reports highlight two things:

• Biology writing leans heavily toward APA or CSE because they handle multiple authors and scientific journals cleanly.
• Your professor or department guidelines always win. If your syllabus says “Use CSE Name–Year,” follow that, even if APA feels easier.

For a quick reference on APA in-text citations and reference lists, the APA Style site is still the gold standard. For CSE, many departments point students to university libraries, such as the UW–Madison CSE guide (writing.wisc.edu).

Examples of citing primary research articles in biology lab reports

Most upper‑level biology lab reports are built around primary research articles. Here’s how you might use and cite them in your Introduction and Discussion.

Example 1: Supporting your hypothesis

Based on previous work showing that light intensity positively correlates with photosynthetic rate in Elodea (Taiz et al., 2018), we hypothesized that increasing light intensity would increase the rate of oxygen bubble production.

Reference list entry (APA):

Taiz, L., Zeiger, E., Møller, I. M., & Murphy, A. (2018). Plant physiology and development (6th ed.). Oxford University Press.

Example 2: Explaining unexpected results

Contrary to our prediction, we did not observe a linear increase in photosynthetic rate at the highest light intensity. Similar saturation effects have been reported in higher plants exposed to high irradiance (Demmig-Adams & Adams, 2006).

Reference list entry (APA):

Demmig-Adams, B., & Adams, W. W. (2006). Photoprotection in an ecological context: The remarkable complexity of thermal energy dissipation. New Phytologist, 172(1), 11–21. https://doi.org/10.1111/j.1469-8137.2006.01835.x

These are the kinds of real examples of citing sources in biology lab reports that instructors are looking for: specific, relevant, and clearly tied to your own data.

Examples of citing lab manuals, protocols, and textbooks

In intro biology labs, your main sources are often the lab manual and a course textbook. Those still need citations.

Lab manual in-text examples

The procedure for preparing the serial dilutions followed the BIOL 110 laboratory manual (Johnson, 2024), with minor modifications to incubation time.

Gram staining was performed according to the department protocol (Department of Biology, 2023).

APA-style reference examples:

Johnson, A. (2024). BIOL 110: General biology laboratory manual (Spring ed.). State University.

Department of Biology. (2023). Microbiology lab protocols [Unpublished laboratory manual]. State University.

Textbook in-text examples

According to Campbell and colleagues, enzyme activity depends strongly on pH because changes in protonation state can alter active site conformation (Reece et al., 2020).

Mendelian inheritance predicts a 3:1 phenotypic ratio in a monohybrid cross when both parents are heterozygous (Freeman et al., 2021).

These examples of citing sources in biology lab reports show that even “everyone knows this” background information still gets a citation when you lean heavily on one source.

Examples of citing websites, databases, and AI tools

Biology lab reports in 2024–2025 often pull in data from online databases and, increasingly, AI tools. That means you need to know how to cite:

• Government or institutional websites
• Public datasets
• AI tools and chatbots (if your instructor allows them)

Government and institutional websites

In‑text examples:

Background information on COVID‑19 transmission was obtained from the U.S. Centers for Disease Control and Prevention (CDC, 2024).

Normal reference ranges for serum cholesterol were taken from Mayo Clinic patient education materials (Mayo Clinic, 2023).

APA-style reference examples:

Centers for Disease Control and Prevention. (2024, March 15). COVID-19: Science brief https://www.cdc.gov/coronavirus/2019-ncov/science/index.html

Mayo Clinic. (2023). Cholesterol levels: What numbers should you aim for? https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/cholesterol-levels/art-20048245

You can apply the same pattern for NIH and other .gov or .org sources. For example, if you use gene or protein information, citing NCBI in a similar format is standard practice.

Online datasets and databases

In‑text examples:

Gene expression values for the control and treatment groups were obtained from the Gene Expression Omnibus (Edgar et al., 2002).

Population‑level survival data were downloaded from the SEER database (National Cancer Institute, 2024).

APA-style reference examples:

Edgar, R., Domrachev, M., & Lash, A. E. (2002). Gene Expression Omnibus: NCBI gene expression and hybridization array data repository. Nucleic Acids Research, 30(1), 207–210. https://doi.org/10.1093/nar/30.1.207

National Cancer Institute. (2024). Surveillance, Epidemiology, and End Results (SEER) Program [Data set]. https://seer.cancer.gov

These are very typical examples of citing sources in biology lab reports that use real‑world public data.

AI tools and chatbots (2024–2025 trend)

Many syllabi now explicitly address AI use. If your instructor allows it, you still have to cite it. An honest example of citing an AI tool in a biology lab report might look like this:

An AI language model (OpenAI ChatGPT, version 4.1, 2025) was used to generate an initial draft of the Introduction, which was then edited for accuracy and style by the authors.

APA-style reference example (adapted from current guidance):

OpenAI. (2025). ChatGPT (Version 4.1) [Large language model]. https://chat.openai.com

Always check your department’s policy. Some treat AI as a tool that must be disclosed; others prohibit it entirely.

How to integrate citations smoothly into each lab report section

The best examples of citing sources in biology lab reports don’t just stick citations at the end; they integrate them logically into each section.

Introduction

Here you’re building a narrative from general background to your specific question. Citations show where your background information and rationale come from.

Example paragraph:

Enzymes accelerate biochemical reactions by lowering activation energy, typically through stabilizing the transition state (Nelson & Cox, 2021). Catalase is a heme-containing enzyme that decomposes hydrogen peroxide into water and oxygen, thereby protecting cells from oxidative damage (National Institutes of Health, 2023). Previous studies have demonstrated that catalase activity increases with temperature up to an optimum, beyond which denaturation sharply reduces activity (Berg et al., 2019). Based on these findings, we predicted that catalase extracted from potato tissue would exhibit maximal activity between 30 °C and 40 °C.

This is a compact example of citing sources in biology lab reports while building a logical argument.

Methods

You don’t cite every pipette move, but you do cite the origin of your protocol or any specialized method.

Example sentences:

The protocol for preparing the catalase extract was adapted from the BIOL 201 laboratory manual (Smith, 2024), with the extraction buffer volume reduced by 50% to increase enzyme concentration.

PCR amplification conditions followed those described by Mullis and Faloona (1987), except that the annealing temperature was increased to 60 °C to improve specificity.

Results

You rarely cite sources here, unless you’re using previously published data for comparison or validating your method against a published standard curve.

Example:

The standard curve for protein concentration (Figure 1) closely matched the linear range reported by Bradford (1976), supporting the reliability of our assay.

Discussion

This is where examples of citing sources in biology lab reports really multiply. You’re constantly comparing your data to other studies.

Example paragraph:

Our finding that catalase activity peaked at 35 °C is consistent with prior work on plant catalase, which reported optimal activity between 30 °C and 40 °C (Berg et al., 2019; Taiz et al., 2018). However, the sharp decline in activity at 50 °C was more pronounced than that observed in purified enzyme preparations (Demmig-Adams & Adams, 2006). One explanation is that our crude extract contained additional proteins and cellular components that destabilized catalase at higher temperatures (Reece et al., 2020).

Notice how each citation supports a specific comparison or explanation, not just a vague “others have shown…”

Common citation mistakes in biology lab reports (and better examples)

Seeing bad practice next to better practice can be clarifying. Here are a few patterns instructors see every semester, with improved examples of citing sources in biology lab reports.

Problem: No citation for specific data or claims

Incorrect: The normal human body temperature is 37 °C.

Better: The normal oral body temperature in healthy adults is approximately 37 °C (Mayo Clinic, 2023).

Problem: Dumping all citations at the end of a paragraph

Incorrect: Enzymes are proteins that speed up reactions. They are not consumed and can be reused many times. They are very specific and work best at certain temperatures and pH (Reece et al., 2020; Nelson & Cox, 2021).

Better: Enzymes are proteins that accelerate chemical reactions without being consumed in the process (Reece et al., 2020). They typically exhibit high substrate specificity and function optimally within a narrow range of temperature and pH (Nelson & Cox, 2021).

Problem: Citing Wikipedia instead of primary or reputable sources

Incorrect: According to Wikipedia, enzymes are biological catalysts (Wikipedia, 2024).

Better: Enzymes are biological catalysts that increase reaction rates by lowering activation energy (Nelson & Cox, 2021).

If you really did start with Wikipedia, use it as a stepping stone to better sources like textbooks, NIH, CDC, or peer‑reviewed articles.

FAQ: Short answers and examples of citing sources in biology lab reports

How many sources should a biology lab report include?
For an intro lab, instructors often expect 3–6 sources: usually the lab manual, the course textbook, and a few outside references (such as a primary article and a reputable website like CDC or NIH). Upper‑level labs may expect 8–15 primary research articles. Your rubric or assignment sheet usually gives a range.

Do I need to cite the lab manual? Can you give an example of how?
Yes. If your procedure or background information comes from the manual, cite it. For example: “Bacterial cultures were incubated at 37 °C overnight (BIOL 210 Laboratory Manual, 2024).” Then list the manual in your references, formatted according to your required style.

Is it okay to use websites like WebMD or Mayo Clinic in a biology lab report?
For human health topics, sites like Mayo Clinic and WebMD are generally acceptable for background information in lower‑division courses, especially when you’re explaining basic physiology or clinical ranges. In advanced courses, instructors usually want primary literature or authoritative .gov/.edu sites instead. If you use them, treat them like any other web source and follow your style guide for citation.

Can you show more examples of citing a journal article in‑text?
Certainly. Here are two more quick examples of citing sources in biology lab reports:

“High salt concentrations can reduce enzyme activity by disrupting ionic interactions within the protein structure (Voet & Voet, 2016).”

“CRISPR–Cas9 has been widely adopted as a tool for targeted genome editing in eukaryotic cells (Jinek et al., 2012).”

Both show the core pattern: statement, then author and year in parentheses.

Do I have to cite AI tools like ChatGPT in my lab report?
If your instructor allows AI and you use it for anything beyond basic spell‑check, you should both disclose and cite it. A simple sentence in the Methods or Acknowledgments, plus a reference entry, is usually enough. Always follow your department’s academic integrity policy.

If you keep these real examples of citing sources in biology lab reports in front of you while you write, you’ll spend less time second‑guessing formatting and more time doing what matters: interpreting your data like a scientist.