Biology · 11th Grade

Active learning ideas

Prions and Viroids

Prions and viroids stretch students’ understanding of infectious disease because they defy the typical models of viruses and bacteria. Active learning helps students confront these exceptions directly, making abstract concepts like protein misfolding and naked RNA more concrete through discussion, mapping, and case analysis.

• Common Core State Standards
• NGSS: HS-LS1-1. From Molecules to Organisms: Structures and Processes. Construct an explanation for how the structure of DNA determines the structure of proteins which carry out the essential functions of life.
• NGSS: HS-LS1-2. From Molecules to Organisms: Structures and Processes. Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms.
• Common Core: CCSS.ELA-LITERACY.RST.11-12.1. Cite specific textual evidence to support analysis of science and technical texts, attending to important distinctions the author makes.

• 30–40 min
• Pairs → Whole Class
• 3 activities

Activity 01

• Socratic Seminar
• 40 min · Whole Class

Socratic Seminar: Can a Protein Cause Disease?

Students read a one-page excerpt on prion biology before class, then engage in a facilitated whole-class discussion. The central prompt is: 'If prions have no DNA or RNA, how do they replicate?' Students must use evidence from the reading and prior knowledge to reason through this question together.

Differentiate between viruses, prions, and viroids based on their composition and mode of infection.

Facilitation Tip

During the Socratic Seminar, pause after each student comment to ask another student to paraphrase or extend the idea, keeping the conversation grounded in evidence from the readings.

What to look for

Pose the question: 'If a prion is just a misfolded protein and has no genetic material, how can it be considered infectious?' Facilitate a class discussion where students must use evidence from their learning to support their arguments, referencing the concept of conformational change.

• Analyze
• Evaluate
• Create
• Social Awareness
• Relationship Skills

Activity 02

• Concept Mapping
• 30 min · Individual

Concept Mapping: Comparing Infectious Agents

Students individually create a concept map connecting viruses, prions, and viroids based on their composition, mode of infection, and target host. They share maps with a partner to identify areas of disagreement, then revise and justify their final version.

Explain how prions can cause neurodegenerative diseases without genetic material.

Facilitation Tip

For the Concept Mapping activity, provide colored pencils or digital tools so students can visually separate structure, disease type, and treatment challenges for each agent.

What to look for

Provide students with a short list of characteristics (e.g., 'contains RNA', 'causes plant disease', 'misfolded protein', 'affects nervous system'). Ask them to match each characteristic to the correct infectious agent: virus, prion, or viroid. Review answers as a class.

• Understand
• Analyze
• Create
• Self-Awareness
• Self-Management

Activity 03

• Case Study Analysis
• 35 min · Small Groups

Case Study Analysis: The BSE Outbreak

Small groups analyze a brief case study on the 1980s-90s BSE crisis in the UK, tracing the epidemiology of prion spread. Groups answer analytical questions about why the disease was so difficult to detect, treat, and contain, and identify the specific biological properties of prions that made containment hard.

Analyze the challenges in treating diseases caused by prions and viroids.

Facilitation Tip

In the Case Study on BSE, assign roles such as epidemiologist, farmer, and public health official to ensure multiple perspectives are represented in the analysis.

What to look for

Ask students to write down one significant challenge in treating prion diseases and one significant challenge in preventing viroid diseases in agriculture. They should briefly explain why each is a challenge.

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

A few notes on teaching this unit

Teaching prions and viroids works best when you emphasize the ‘what’s missing’ approach. Highlight that prions lack nucleic acid entirely and viroids lack protein coats, which explains why immune systems and medicines struggle to target them. Avoid overcomplicating with protein biochemistry; focus instead on the functional consequences of missing components. Research shows students grasp these concepts more easily when they compare agents side-by-side rather than studying them in isolation.

By the end of these activities, students will confidently distinguish prions, viroids, and viruses based on structure and mechanism, explain why standard treatments fail against them, and apply this knowledge to real-world outbreaks like BSE. Success looks like clear articulation of misfolding chains, precise classification of agents, and thoughtful discussion of treatment barriers.

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Watch Out for These Misconceptions

• During Concept Mapping: Comparing Infectious Agents, watch for students who incorrectly group prions with viruses because both cause disease. Redirect by having them compare the composition column first: viruses have DNA/RNA and protein, prions have protein only.

  Use the concept map’s structure column to guide students to note that prions contain no nucleic acid, while viruses always include genetic material. Ask them to highlight this difference in a different color on their maps.

• During the Case Study: The BSE Outbreak, listen for students who assume prion diseases can be cured like bacterial infections. Redirect by having them review the case’s timeline and treatment section to identify why medications failed.

  Ask students to annotate the case study with evidence about treatment attempts, then discuss as a class why the absence of a genome or metabolic activity makes prions untreatable with standard drugs.

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Methods used in this brief

• Socratic Seminar
• Concept Mapping
• Case Study Analysis