Biology · 10th Grade

Active learning ideas

Gene Expression and Epigenetics

Active learning works well for gene expression and epigenetics because students often confuse genetic sequence changes with reversible chemical modifications. Hands-on modeling and data analysis let them see how chromatin structure and transcription factor binding actually function, making abstract concepts concrete and memorable.

• Common Core State Standards
• HS-LS1-1

• 20–40 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Case Study Analysis
• 35 min · Pairs

Physical Modeling: Histone Modification and Gene Access

Students use yarn (DNA) wrapped tightly around paper tubes (histones) to build a condensed chromatin model. They simulate acetylation by loosening the wrapping around specific regions and test whether they can access an underlying gene (a printed message). They record which genes are accessible in their model and write an explanation of how histone modification controls gene expression without changing the DNA sequence.

Explain how two cells with identical DNA can have completely different structures and functions.

Facilitation Tip

During Physical Modeling, circulate with the histone spool and DNA string to ask guiding questions like, 'Where would a transcription factor bind if histones were acetylated?' to keep students focused on functional outcomes.

What to look for

Present students with two scenarios: one describing a mutation in a gene, and another describing a change in histone acetylation. Ask students to write one sentence for each scenario explaining whether the DNA sequence itself has changed and how gene expression might be affected.

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management

Activity 02

• Case Study Analysis
• 40 min · Small Groups

Data Analysis: Comparing Epigenomes

Provide simplified epigenome visualization data from two different cell types (liver vs. skin cells, using publicly available ENCODE data graphics). Students identify regions with different methylation or acetylation patterns, infer which genes are differentially expressed, and propose a biological explanation for why those genes would need to be on in one cell type and off in the other.

Analyze how environmental factors like diet or stress can leave 'marks' on our DNA.

Facilitation Tip

For Data Analysis, provide printed epigenome heatmaps before students access the online tool so they practice interpreting static data before manipulating variables.

What to look for

Pose the question: 'If identical twins have the same DNA, why might their health outcomes or susceptibility to certain diseases differ as they age?' Guide students to discuss the role of environmental influences and epigenetic modifications in these differences.

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management

Activity 03

• Think-Pair-Share
• 20 min · Pairs

Think-Pair-Share: Same DNA, Different Cell

Show students paired images of a neuron and a hepatocyte and ask them to explain how two cells with identical DNA sequences can have such different structures and functions. After sharing with a partner, groups present their explanations and the class categorizes the mechanisms mentioned into a shared framework of transcription factor activity and epigenetic regulation.

Evaluate the impact of histone acetylation on gene accessibility and expression.

Facilitation Tip

In Think-Pair-Share, assign roles explicitly: one student explains the DNA similarity, another the gene activation differences, and a third connects it to environmental exposure, to ensure equitable participation.

What to look for

Ask students to draw a simplified diagram showing how histone acetylation might affect a gene's accessibility to transcription machinery. They should label the histone, DNA, acetyl group, and indicate whether the gene is more or less likely to be expressed.

• Understand
• Apply
• Analyze
• Self-Awareness
• Relationship Skills

Activity 04

• Case Study Analysis
• 30 min · Small Groups

Case Study Analysis: Environment and the Epigenome

Present research from the Dutch Hunger Winter cohort or early-life stress and cortisol receptor methylation studies. Groups analyze the evidence, identify the epigenetic mechanism involved, and discuss what the findings suggest about the inheritance of environmental experience, including the important limits of that inheritance and how it differs from Lamarckian inheritance.

Explain how two cells with identical DNA can have completely different structures and functions.

Facilitation Tip

In the Case Study, pause after reading to ask students to predict what would happen to gene expression if cortisol levels remained high for months, linking their prior knowledge to the new scenario.

What to look for

Present students with two scenarios: one describing a mutation in a gene, and another describing a change in histone acetylation. Ask students to write one sentence for each scenario explaining whether the DNA sequence itself has changed and how gene expression might be affected.

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management

A few notes on teaching this unit

Experienced teachers approach this topic by starting with students’ observations about cells looking different despite having the same DNA. We avoid starting with abstract definitions of promoters or transcription factors because those terms won’t stick if students haven’t felt the tension of 'same DNA, different outcomes.' Use analogies carefully; many students already think of genes as 'on or off switches,' so we build from that to show dimmer switches and locks instead. Research shows that students who draw chromatin structures while explaining gene regulation retain more than those who only hear lectures, so pair modeling with immediate verbal explanations.

By the end of these activities, students should explain how histone modifications and DNA methylation regulate gene access without altering DNA sequence. They should use models and data to connect mechanisms to real cell differentiation and environmental effects, and distinguish epigenetic changes from mutations.

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Watch Out for These Misconceptions

• During Physical Modeling, watch for students who say the histone spool changes the DNA letters when they add or remove acetyl groups.

  As students model histone acetylation, ask them to physically rotate the spool to show how the DNA becomes more accessible. Emphasize that the DNA sequence remains unchanged by pointing to the letters written on the string and asking, 'Can you read the letters now that the spool is looser?' This grounds the activity in observable structure rather than abstract marks.

• During Data Analysis, watch for students who interpret a red mark on an epigenome heatmap as a 'broken gene' rather than a silenced one.

  While students compare methylated and non-methylated regions, ask them to describe what 'red' means in terms of transcription factor binding. Direct them to the legend and ask, 'Would a transcription factor be more likely to land here or over here?' to refocus on gene access instead of gene damage.

• During the Case Study, watch for students who claim that famine exposure will definitely change their own children’s DNA sequence.

  As students discuss the Dutch Hunger Winter data, pause and ask them to reread the footnote about which epigenetic marks were measured. Then ask, 'Do these marks affect the letters of the DNA, or something else about how it’s read?' This redirects the conversation from permanent sequence change to reversible gene regulation.

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Methods used in this brief

• Case Study Analysis
• Think-Pair-Share