Q1. [5] deep thorough-understanding
Tooth enamel is the hardest substance in the human body, yet it gets corroded after eating sugary food. Explain the sequence of events responsible for this, and suggest one way to prevent it.
Generated by claude-sonnet-4-6 · 2026-06-26 01:04 · grounding rag
Model Answer
Sequence of events leading to tooth enamel corrosion:
- When we eat sugary food, bacteria present in the mouth act on the sugars (simple carbohydrates) and produce acids.
- These acids attack and demineralise the tooth enamel, causing gradual softening — this is called dental caries (tooth decay).
- Bacterial cells, along with food particles, stick to the teeth forming dental plaque, which covers the tooth surface.
- The plaque prevents saliva from reaching the tooth surface. Normally, saliva would neutralise the acid, but plaque blocks this protective action.
- If untreated, the microorganisms penetrate deeper, invading the pulp, causing inflammation and infection.
Prevention:
Brush teeth immediately after eating to remove plaque before the bacteria can produce acids, allowing saliva to neutralise any remaining acid and protect the enamel.
Source: Chapter 5, Section 5.2.4 — "More to Know: Dental Caries"
---
Explanation
- The examiner expects the full chain: sugar → bacteria → acid → demineralisation → plaque formation → saliva blocked → pulp infection.
- All key terms (dental caries, demineralise, plaque, saliva) should appear — they are directly from the "More to Know" box and fetch marks.
- One clear prevention point (brushing after eating) is sufficient; don't list multiple vague ones.
- The word "corrosion" in the question is a hook to the chemistry chapter, but the actual answer is entirely from Chapter 5's dental caries box — stay grounded there.