How to Write an Active Vs Passive Voice for Biology

Biology students must navigate the delicate balance between the traditional objectivity of the passive voice and the modern clarity of the active voice. Choosing the correct voice is unique in biology because it distinguishes between the researcher's actions and the natural processes occurring within an organism or ecosystem.

What Is an Active Vs Passive Voice in Biology?

In biology, active voice occurs when the subject performs the action (e.g., 'The enzyme catalyzed the reaction'), while passive voice occurs when the subject receives the action (e.g., 'The reaction was catalyzed by the enzyme'). Unlike humanities, biology writing uses passive voice to emphasize the organism or result over the researcher, but increasingly favors active voice for describing experimental procedures and logical conclusions.

Before You Start

• Check the specific style guide of the journal you are targeting, such as Nature or The Journal of Cell Biology.
• Identify whether the focus of your sentence is the researcher (the 'doer') or the biological specimen.
• Review your Materials and Methods section to determine if you are overusing 'was' and 'were'.
• Clarify the specific biological mechanism you are describing to ensure the subject-verb relationship is accurate.

Use Active Voice for Experimental Justification

When explaining why you chose a specific methodology or animal model, use the active voice to take ownership of the intellectual decision.

Example: We chose Arabidopsis thaliana as a model organism due to its rapid life cycle and sequenced genome.

Tip: Avoid 'It was decided that...'; it obscures who made the scientific choice.

Apply Passive Voice to Standard Laboratory Procedures

In the Materials and Methods section, use passive voice when the person performing the action is irrelevant to the outcome of the protocol.

Example: The PCR products were electrophoresed on a 1.5% agarose gel at 100V for 45 minutes.

Tip: Focus the reader's attention on the DNA or protein, not the student holding the pipette.

Describe Biological Processes Using Active Voice

To make biological mechanisms sound dynamic and accurate, let the biological agent be the subject of the sentence.

Example: The motor protein kinesin transports vesicles along microtubule tracks toward the cell periphery.

Tip: This helps avoid wordy sentences like 'Vesicles are transported by kinesin...'

Use Active Voice for Interpretations and Conclusions

When you are interpreting data in the Discussion section, the active voice conveys confidence in your scientific findings.

Example: Our data suggest that the mutation in the BRCA1 gene significantly reduces DNA repair efficiency.

Tip: Using 'suggest' or 'indicate' in the active voice is standard practice in high-impact biology journals.

Switch to Passive Voice to Emphasize the Affected Variable

If the most important part of the sentence is the change in a biological variable, use the passive voice.

Example: Glucose levels were measured every ten minutes following the administration of insulin.

Tip: This keeps the focus on the physiological response rather than the technician.

Identify and Remove 'To Be' Verbs in Results Sections

Scan your Results section for 'was' or 'were' and determine if the biological subject can perform the action directly.

Example: Original: A significant increase in biomass was observed. Revised: Biomass increased significantly in the nitrogen-enriched plots.

Tip: Removing 'was observed' makes your results sound more direct and authoritative.

Use Active Voice to Cite Previous Researchers

When attributing a discovery to a specific lab or scientist, the active voice is more concise and respectful.

Example: Mendel proposed the law of independent assortment based on his studies of pea plants.

Tip: This is more efficient than writing 'The law of independent assortment was proposed by Mendel.'

Common Mistakes to Avoid

• Using passive voice to hide a lack of evidence (e.g., 'It is thought that...' without a citation).
• Overusing 'We' in the Methods section, which can make a formal report sound like a personal diary.
• Dangling participles in passive sentences, such as 'After staining the slides, the nuclei were visible' (the nuclei didn't stain the slides).
• Switching voices inconsistently within a single paragraph of a lab report.
• Assuming that passive voice is 'more scientific' when it actually makes complex pathways harder to follow.

Pro Tips

• Read your abstract aloud; if it feels sluggish, convert the final concluding sentence to active voice.
• Check the 'Instructions for Authors' in the Journal of Biological Chemistry; they explicitly encourage active voice for clarity.
• Use active voice when describing the 'behavior' of molecules, such as 'The ligand binds to the receptor.'
• Reserve the passive voice for when the actor is truly unknown, such as 'The species was first identified in the Amazon basin.'
• Keep the subject and verb close together to avoid confusion in long sentences about metabolic pathways.

Frequently Asked Questions

Is it okay to use 'I' or 'We' in a biology lab report?

Yes, most modern biology journals prefer 'We' in the Methods and Discussion sections to clearly distinguish the researchers' actions from natural phenomena.

When is passive voice preferred in biology?

Passive voice is preferred in the Materials and Methods section when the focus is on the treatment of the samples rather than the individual researcher.

Does active voice make biology writing less objective?

No, objectivity comes from your data and logic; active voice simply makes the description of that data clearer and more readable.

Should I use active or passive voice for my thesis abstract?

Use a mix: active voice for your main findings and conclusions to show impact, and passive voice for the background context if the focus is on established facts.

Related Resources

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• How to Write a Sentence Rewriting for Biology

• How to Write Topic Sentences for Biology

• How to Write a Paragraph Structure for Biology

• Find Peer-Reviewed Sources with Sourcely

• Polish Your Writing with Revise AI