Photosynthesis
Exam-ready definition
The process by which plants synthesise carbohydrates from carbon dioxide and water, using energy from light trapped by chlorophyll. Word equation: carbon dioxide + water → glucose + oxygen, in the presence of light and chlorophyll.
How this is marked
The balanced symbol equation (6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂) is Extended-only and worth learning cold. Limiting factor questions (light, CO₂, temperature) are the most common 4-6 mark application.
In an exam answer
Stating the role of chlorophyll: 'Chlorophyll absorbs light energy, which is used to convert carbon dioxide and water into glucose and oxygen during photosynthesis.'
Full topic guide: Plant nutrition
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