Invisible Enemy

Overview

Today’s lesson introduces viruses as microscopic organisms that can only reproduce inside a host. You will explore virus structure and the basic steps of how viruses interact with human cells.

Learning intentions

• WALT: Understand what a virus is and how it interacts with human cells.
• WALT: Recognise that viruses need a host to reproduce.
• WALT: Explain, using simple diagrams, key parts of a virus.

Success criteria

• I can describe what a virus is using age-appropriate science language.
• I can label the main structure of a virus (for example: genetic material, protein coat, and spikes/capsid).
• I can explain why a virus must enter a host cell to make copies.
• I can use a simple sequence diagram to show virus–cell interaction.

Curriculum links

• Science: Living world—understanding interactions between living things and systems (including how disease agents affect humans).
• Science capabilities—gather and interpret information, use evidence to explain phenomena.
• Key competencies—thinking critically (explaining cause and effect) and communicating ideas clearly.

Lesson structure (60 minutes)

1. 0–5 Warm-up (Think–Pair–Share): “What makes something ‘alive’?” Students share ideas in pairs, then class compiles a short list. Teacher notes common misconceptions (for example, “all microbes are living”).

2. 5–15 Mini-lesson: What is a virus? Use a clear, student-friendly explanation: viruses are very small particles with genetic material inside a protein coat; they cannot reproduce on their own and require host cells. Students add 3–4 bullet notes to a “Virus Basics” template.

• Dyslexia-friendly option: Provide the template with prompts and short lines already printed.

3. 15–25 Guided visuals: Virus structure diagram. Teacher displays a labelled diagram (printed or projected). Students recreate it in their workbook using simple shapes. Include spikes (where relevant), capsid/protein coat, and genetic material.

• Quick check: “Point to the part that is the ‘instruction set’.” Students respond using the diagram they drew.

4. 25–40 Modelling interaction with human cells (Sequence cards). In groups of 3–4, students sort and arrange picture/word cards showing a basic sequence: attachment to cell, entry/uncoating (simplified), using cell machinery to make copies, assembly/release. Groups then paste or draw the sequence in order.

• Teacher circulates, asking: “What tells you the virus needs a host?”

5. 40–50 Whole-class sense-making (Evidence talk). Each group shares one key step and their reasoning. Teacher uses a class anchor chart:

• “Viruses need hosts because…” → they use host cell machinery to reproduce.
• Students update their notes with one sentence of explanation.

6. 50–55 Formative assessment (Exit check). Students complete a short exit task:

• Draw and label a virus (minimum 2 labels).
• Write one sentence: “A virus must enter a host cell because…”. Collect for quick review.

7. 55–60 Close and preview next lesson. Teacher explains that next lessons will explore how viruses spread and how medicine and prevention help. Students share one question they want answered.

Resources

• Printed “Virus Basics” note template with bullet lines
• Simple labelled virus diagram (capsid/protein coat, genetic material, spikes)
• Virus structure drawing guide (shapes to trace)
• Set of sequence cards for virus–cell interaction (pictures + short words)
• Student workbooks or A3 paper for group sequence diagrams
• Markers/coloured pencils
• Sticky notes for class anchor chart
• Exit check slip (drawing + one sentence)
• Optional: picture-backed sentence starters for students who need support

Assessment

• Observations during group card sequencing (listening for correct cause-and-effect: host requirement).
• Formative exit task: labelled structure and an accurate one-sentence explanation.
• Quality of student diagrams (labels and clear sequencing).

Differentiation

• Support:
• Provide sentence starters: “A virus is…”, “It needs a host because…”.
• Use partially completed diagrams with key parts already drawn.
• Offer audio-read instructions and simplified card sets (fewer steps).
• Challenge/extension for advanced learners (still aligned to the lesson):
• Ask students to add an extra label (for example, “envelope if present”) and explain how attachment differs by virus type.
• Include a “comparison box”: What changes between viruses (shape/spikes) but the host requirement stays the same.
• EAL learners:
• Emphasise visuals first; pair students with a supportive peer.
• Use consistent language across slides and cards (attach, enter, copy, release).
• SEN/dyslexia-friendly:
• Bullet-based notes only; avoid long paragraphs.
• Provide reduced-text cards and high-contrast visuals.
• Allow verbal responses to the exit sentence (teacher scribe if needed).

Extension (optional)

• Research a specific virus and its impact on humans (short class-friendly task for the next session). Students should find:
• What the virus affects (respiratory, blood, etc.)
• A basic sign/symptom example
• How it spreads (one route)
• One prevention or treatment idea Present findings using a simple poster or 3–4 bullet points.