Types of Pathogens

Active learning works well for this topic because students need to distinguish between microscopic agents that behave very differently. Movement, visual comparison, and role-play help students remember size differences and infection processes that textbooks alone cannot convey.

• Year 10
• Biology
• 3 activities
• 25 min–35 min

Learning Objectives

1. Classify given microorganisms as viruses, bacteria, protists, or fungi based on their structural characteristics.
2. Compare and contrast the modes of infection and reproduction for bacteria and viruses.
3. Explain how protists and fungi cause disease, providing specific examples of host interactions.
4. Analyze the structural differences between bacteria and viruses to justify why viral infections are often harder to treat.

Simulation Game

⏱ 30 min·Whole Class

Simulation Game: The Outbreak Game

Students are given 'status' cards (susceptible, infected, or immune). They move around the room and 'transmit' the disease through handshakes, tracking how quickly the infection spreads through the population.

Prepare & details

Justify why viral infections are often harder to treat than bacterial infections.

Facilitation Tip: During The Outbreak Game, freeze the simulation at key moments so students can articulate why certain actions slowed or sped up transmission.

Setup: Flexible space for group stations

Materials: Role cards with goals/resources, Game currency or tokens, Round tracker

• Apply
• Analyze
• Evaluate
• Create
• Social Awareness
• Decision-Making

Gallery Walk

⏱ 35 min·Small Groups

Gallery Walk: Pathogen Profiles

Set up stations for diseases like Salmonella, Gonorrhoea, Malaria, and Rose Black Spot. Students move around to identify the pathogen type, symptoms, and methods of prevention for each.

Prepare & details

Differentiate between the structural features of bacteria and viruses.

Facilitation Tip: While students present their Pathogen Profiles, circulate with a checklist to ensure every group covers structure, size, and disease example without copying.

Setup: Wall space or tables arranged around room perimeter

Materials: Large paper/poster boards, Markers, Sticky notes for feedback

• Understand
• Apply
• Analyze
• Create
• Relationship Skills
• Social Awareness

Think-Pair-Share

⏱ 25 min·Pairs

Think-Pair-Share: Global Health History

Students discuss how historical events, such as the expansion of the British Empire, affected the global spread of diseases like smallpox or cholera, and how this shaped modern public health policies.

Prepare & details

Explain how different types of pathogens cause disease in their hosts.

Facilitation Tip: After the Think-Pair-Share, insist each pair produce one written sentence summarizing how historical outbreaks changed public health measures.

Setup: Standard classroom seating; students turn to a neighbor

Materials: Discussion prompt (projected or printed), Optional: recording sheet for pairs

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

Teaching This Topic

Teachers often start with size comparisons because viruses and bacteria are invisible yet cause vastly different diseases. Avoid rushing to treatment details before students grasp the biological differences. Research shows students retain more when they draw life cycles themselves rather than copying from slides.

What to Expect

By the end, students should confidently classify pathogens, explain their transmission routes, and justify why certain treatments work only for some microbes. Success looks like precise vocabulary, accurate diagrams, and clear comparisons in discussions.

Watch Out for These Misconceptions

Common Misconception

During The Outbreak Game, watch for students who assume all microbes spread the same way.

What to Teach Instead

Pause the game after the first round and ask groups to explain which pathogen type their microbe represented and how its transmission differed from others.

Common Misconception

During Pathogen Profiles, watch for students who confuse virus and bacteria size or structure.

What to Teach Instead

Provide a blank scale diagram during the activity and ask students to sketch their pathogen to scale alongside a host cell, labeling size differences in nanometers or micrometers.

Assessment Ideas

Quick Check

After Gallery Walk, give students images or brief descriptions of four microorganisms. Ask them to identify each as a virus, bacterium, protist, or fungus and provide one key characteristic that led to their classification.

Discussion Prompt

During Think-Pair-Share, pose the question: 'Why can doctors prescribe antibiotics for a bacterial throat infection but not for a viral cold?' Facilitate a class discussion where students explain the fundamental differences in how bacteria and viruses cause illness and reproduce.

Exit Ticket

After The Outbreak Game, have students draw a simple diagram illustrating how a virus infects a host cell and, in a separate box, draw a simple diagram showing how a bacterium reproduces. Ask them to label one key difference between the two processes.

Extensions & Scaffolding

• Challenge: Ask students to research a lesser-known pathogen (e.g., prions) and create a new gallery card with comparisons to existing profiles.
• Scaffolding: Provide a partially completed table with pathogen types on one axis and transmission routes on the other; students fill gaps during the Gallery Walk.
• Deeper exploration: Have students design a public health poster targeting one specific pathogen, including transmission prevention and treatment options.

Key Vocabulary

Pathogen	A microorganism, such as a bacterium, virus, or fungus, that can cause disease.
Virus	An infectious agent with a simple structure, typically consisting of genetic material (DNA or RNA) surrounded by a protein coat. Viruses can only replicate inside the living cells of other organisms.
Bacteria	Single-celled microorganisms with a cell wall and cell membrane, but lacking a nucleus. Bacteria can reproduce independently and can cause disease through toxins or by damaging host tissues.
Protist	A diverse group of eukaryotic microorganisms, some of which are pathogenic. Examples include amoebas and Plasmodium, which causes malaria.
Fungi	Eukaryotic organisms that include yeasts, molds, and mushrooms. Some fungi are pathogenic, causing infections like athlete's foot or thrush.