Q1. [3] medium thorough-understanding
Where do plants obtain each of the raw materials required for photosynthesis?
Generated by claude-sonnet-4-6 · 2026-06-11 09:38 · grounding rag
Model Answer
Plants obtain the raw materials for photosynthesis from the following sources:
- Carbon dioxide – Absorbed from the atmosphere through tiny pores called stomata present on the surface of leaves.
- Water – Absorbed from the soil by the roots and transported to the leaves (in terrestrial plants).
- Sunlight – Obtained from the sun; its energy is absorbed by the pigment chlorophyll present in chloroplasts.
- Minerals (e.g., nitrogen, phosphorus, magnesium) – Taken up from the soil through roots, along with water.
Source: Chapter 5, Section 5.2.1 – Autotrophic Nutrition
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Explanation
- Examiners expect all three/four raw materials to be named with their sources — missing even one costs marks.
- Key terms to use: stomata, roots, chlorophyll — these show understanding, not just memorisation.
- Carbon dioxide → atmosphere via stomata; Water → soil via roots; Sunlight → sun via chlorophyll. Minerals (nitrogen etc.) from soil is a bonus point that shows thorough reading.
- Do not write lengthy definitions; one crisp line per raw material is sufficient for a 3-mark answer.