Cambridge IGCSE Biology 0610 · Topic 6.1
Photosynthesis
Photosynthesis is not simply plants making food. It is an energy-transfer process in which a plant builds carbohydrate from two very ordinary raw materials, using energy it captures from light — and almost every mark in this topic depends on keeping those two ideas, matter and energy, properly separate.
Follow the chain the syllabus actually tests: raw materials → light energy → carbohydrate → what the plant then does with that carbohydrate. The raw materials are carbon dioxide and water. Light is not a raw material; it is the energy source, and chlorophyll is what makes that energy usable, by transferring it from light into chemical energy the plant can spend on building glucose. Oxygen comes out as a product on the other side.
That gives you the core of the process, but Cambridge tests three separate skills built on top of it, and each has its own page here. First, you need the precise chemistry — the equations, chlorophyll’s exact role, and what happens to the glucose once it exists. Second, you need to be able to design and interpret the experiments that prove light, chlorophyll and carbon dioxide are genuinely required, not just assumed. Third, you need to describe — and, if you are Extended, explain — how fast photosynthesis goes when you change the conditions it depends on.
Where to go next
| Page | Level | What it covers |
|---|---|---|
| The equation, chlorophyll and mineral requirements | Core (balanced equation: Supplement) | The word and balanced equations, what chlorophyll transfers, the five fates of the carbohydrate made, and why plants need nitrate and magnesium ions. |
| Investigating what photosynthesis needs | Core · Practical | Destarching, the iodine starch test, and the experiments that prove light, chlorophyll and carbon dioxide are all required. |
| Rate and limiting factors | Core (limiting factors: Supplement) | How light intensity, carbon dioxide concentration and temperature change the rate, and which factor is actually holding it back. |
Core or Supplement within 6.1?
Everything above the level of individual pages is Core: the raw materials, the word equation, chlorophyll, the carbohydrate’s fates, the mineral ions, and every one of the required practicals. The two exceptions sit inside specific pages rather than being whole topics of their own — the balanced chemical equation on the equation page, and limiting factors on the rate page — so Core candidates can use every page here, just stopping before those two sections.