Pearson Edexcel International GCSE Biology · specification 4BI1 · Paper 2 | Whole paper: All content including bold B statements · Free · no account needed
2(e) Nutrition (4BI1 specification)
Photosynthesis in plants and digestion in humans — the two ways organisms in this specification obtain the molecules they need.
Learn it on Incandio
The 9 Incandio pages that teach this — each explained in full, then proved in marked questions, taught back to an AI pupil and defended in a debate. Completely free.
- Photosynthesis — How a plant builds itself out of air, where the energy for that comes from, and the one job the soil is actually doing.
- What Limits Photosynthesis — Why brightening the light eventually stops working, how to read that off a graph, and the experiments that prove what a plant needs.
- The Leaf: Structure and Gas Exchange — Every feature of a leaf is a solution to one conflict — letting carbon dioxide in through holes that also let water out.
- A Balanced Diet — Why you can eat plenty and still be starving — food does several separate jobs, and having enough of one does not cover the others.
- The Alimentary Canal — One long tube whose contents are still outside you, and the muscular squeeze that moves them along it.
- Digestive Enzymes and Bile — The demolition tools that cut food molecules small enough to absorb — and the one secretion that does the job without being an enzyme at all.
- Absorption and the Energy in Food — How a tube half a square metre in area absorbs an entire diet — and how to measure the energy a food actually contains.
- Respiration and ATP — What respiration is actually for, why every living cell does it every second, and why breathing is not the same thing at all.
- Anaerobic Respiration — The backup that runs without oxygen — why it is worth having, why it cannot last, and why bread and beer both depend on it.
The teaching route this belongs to: Topic 2 · Structures and functions in living organisms (Biology) — the lessons in order, with every gate.
Specification coverage
Topic 2 Structures and functions in living organisms (e) Nutrition — statements 2.20–2.36B (includes bold B statements assessed on Paper 2 only)
Assessment objectives: AO1, AO2, AO3. Suggested learning time: 110 minutes.
Required knowledge
- The word and balanced chemical equations for photosynthesis
- How light intensity, carbon dioxide concentration and temperature affect the rate of photosynthesis, and the idea of a limiting factor
- Leaf structure and how it is adapted for photosynthesis
- The need for mineral ions: nitrate for amino acids and magnesium for chlorophyll
- The human alimentary canal and the function of each region
- The role of digestive enzymes: amylase, protease and lipase, and where each acts
- The role of bile in emulsification and in neutralising stomach acid
- Bold B statements: absorption in the small intestine and the adaptations of the villi in greater depth
Required skills
- Interpret a rate-of-photosynthesis graph and identify the limiting factor at each stage
- Explain a structural adaptation in terms of the function it serves
- Match an enzyme to its substrate, product and site of action
- Describe and evaluate the required practical: Investigate photosynthesis, for example the production of oxygen by pondweed at different light intensities, and test a leaf for starch.
How it is examined
- Multiple-choice and short-answer recall
- Application of the content to an unfamiliar context
- Extended open-response, marked on the quality of a connected explanation
- Practical questions on method, variables, data and sources of error
Common mistakes
- Saying bile digests fat. Bile emulsifies fat into droplets, increasing the surface area for lipase — it contains no enzymes.
- Reading a photosynthesis graph's plateau as 'the plant is full'. Some other factor has become limiting, and naming it is the mark.
- Confusing where each enzyme acts. Protease in the stomach and in the small intestine are different enzymes at different pH.
This page maps the specification. The pages above teach it, and the Biology lessons hold the whole course — completely free.