Cambridge IGCSE Biology 0610 · Topic 6
Plant Nutrition
A plant does not get its carbohydrate by eating anything. It builds carbohydrate itself, from carbon dioxide and water, using energy captured from light — and once you hold onto that one fact, most of this chapter falls into place around it.
Cambridge splits Chapter 6 into two syllabus points that fit together more tightly than they first appear. 6.1 Photosynthesis covers what the process needs, what it produces, how you prove those requirements experimentally, and what makes the rate speed up or slow down. 6.2 Leaf structure then asks a different question about the same process: given everything photosynthesis needs, how is a leaf actually built to deliver it? Every structure you have to name in a leaf diagram exists because of something 6.1 already told you the plant needs.
Most lost marks in this chapter come from precision, not from missing knowledge. Students generally know that plants photosynthesise using light — the mark is usually lost over whether light gets written as a raw material instead of a condition, whether a diagram label gets attached to the wrong tissue, or whether a rate graph gets read as “the light must be limiting” when the curve has already flattened out. The pages below are built around exactly those precision points.
What’s in this chapter
| Page | Level | What it covers |
|---|---|---|
| Photosynthesis | Core | What photosynthesis actually needs and produces, and why it is an energy-transfer process rather than just "plants making food." |
| The photosynthesis equation and chlorophyll | Core (balanced equation: Supplement) | The word equation, the balanced equation, what chlorophyll actually does, the five fates of the carbohydrate a plant makes, and why plants need nitrate and magnesium ions. |
| Investigating what photosynthesis needs | Core · Practical | Destarching, the iodine starch test, and the three experiments that prove light, chlorophyll and carbon dioxide are all required. |
| Rate and limiting factors of photosynthesis | Core (limiting factors: Supplement) | How light intensity, carbon dioxide concentration and temperature change the rate, and how to work out which factor is actually holding it back. |
| Leaf structure and adaptations | Core · Practical | Every named structure in a dicotyledonous leaf, identified from real diagrams and linked to exactly what it does for photosynthesis. |
Core or Supplement?
Almost everything in this chapter is Core. The only Supplement-only content sits in two specific places: the balanced chemical equation for photosynthesis, and limiting factors— working out which environmental factor is actually restricting the rate at a given point on a graph. Everything else, including all of leaf structure, is examined at both Core and Extended level. If you are sitting Core only, you can skip those two sections entirely without leaving a gap anywhere else in the chapter.
The practical (Paper 6) content is concentrated in three places: the starch-test and requirement experiments together with the hydrogencarbonate-indicator investigation on the practicals page, the rate investigations using an aquatic plant, and identifying leaf structures correctly in diagrams you have not seen before. All three reward the same underlying skill — reasoning about a method and its evidence, rather than recalling a fact.