Biology (0610) Plant Nutrition Revision Note

This document covers plant nutrition for CAIE IGCSE Biology, focusing on photosynthesis and mineral requirements. Photosynthesis is defined as the process by which plants manufacture carbohydrates from raw materials using light energy trapped by chlorophyll. Extended students must know the balanced chemical equation. The guide explains how carbon dioxide enters through stomata and water is absorbed by roots, with glucose used for respiration, storage as starch, making cellulose, or transport as sucrose. It details essential mineral ions: nitrate for amino acids (deficiency causes stunted growth) and magnesium for chlorophyll (deficiency causes yellowing leaves). Practical investigations are included: testing the role of chlorophyll (using variegated leaves), light intensity (starch test with stencil), and carbon dioxide concentration (bell jar experiment with NaHCO₃ and NaOH). Limiting factors such as light, CO₂, and temperature are explained using rate of photosynthesis curves. The structure of a dicot leaf is described with functions of waxy cuticle, mesophyll cells, vascular bundles, stomata, and guard cells. Adaptations for photosynthesis, including large surface area, thin leaves, chlorophyll concentration, and vein networks, are also highlighted. This resource equips students with a complete understanding of how plants produce food, the role of minerals, and experimental techniques for exam success.