Pearson Edexcel International GCSE in Biology · 4BI1

Biology

Life, from a single cell to a whole ecosystem. Biology rewards students who can explain a PROCESS — how one thing causes the next — rather than recite a list, and every lesson here is built to teach it that way.

How the qualification is assessed

Two untiered papers. Paper 1 is 110 marks in 2 hours and covers the core content; Paper 2 is 70 marks in 1 hour 15 minutes and covers everything, including the bold B statements. There is no practical exam — experimental skills are tested in writing.

Incandio is aligned to this specification. It is not published by, endorsed by or affiliated with Pearson, and it reproduces none of Pearson's wording — the statement numbers are given so you can check every lesson against your own copy.

68 lessons across 5 topics

They cover 176 of the 176 statements on the specification.

Topic 1 · The nature and variety of living organisms

What makes something alive, and the five kinds of living thing — plus viruses, which are not one. Short, but it supplies the vocabulary every later topic assumes.

• What Makes Something Alive — The eight processes every living organism carries out — and why a fire, which seems to do several of them, is not alive.
• The Four Eukaryote Groups — Plants, animals, fungi and protoctists — how to tell them apart from their features, and the named examples the specification expects.
• Bacteria, Viruses and Pathogens — What a prokaryote is, why a virus is not classed as living at all, and what the word pathogen actually covers.

Topic 2 · Structures and functions in living organisms

The biggest topic by far: cells, enzymes, transport, photosynthesis, digestion, respiration, gas exchange, circulation, excretion and the nervous and hormonal systems. Roughly half the qualification lives here.

• Levels of Organisation — From organelle to organism — the five-step ladder that every later topic in biology is built on.
• Comparing Cells, and Stem Cells — What plant and animal cells share and where they differ — then why a cell specialising is one of the most powerful ideas in biology.
• Carbohydrates, Proteins and Lipids — The three big food molecules — what they are made of, what they are built from, and how to test for them.
• Enzymes: Catalysts With a Shape — Why a protein with a hole in it speeds up a reaction, and why heat destroys that ability permanently.
• Enzymes and pH — Why acid ruins one enzyme and is the only condition another will work in — and how to find an enzyme's best pH by experiment.
• Diffusion, Osmosis and Active Transport — The three ways anything gets into or out of a cell — which need energy, which do not, and what makes each one fast or slow.
• 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 Thorax and Ventilation — You cannot suck air in. Breathing works by changing the size of a sealed box — and every part of the chest is built for that one job.
• Alveoli, Exercise and Smoking — Why a lung holds a tennis court's worth of surface, what exercise does to breathing, and exactly how smoking dismantles both.
• Why Transport Systems Exist, and the Two Plant Vessels — Diffusion is fast across a cell and hopeless across a body. That single fact explains why big organisms need plumbing — and what a plant's two pipes carry.
• Water Uptake and Transpiration — A tall tree lifts water a hundred metres with no pump and no moving parts. The force comes from water evaporating out of its leaves.
• Blood — Four components in one fluid — and each one is shaped, or shaped away, for exactly what it has to carry.
• Immunity and Clotting — You are a warm, wet, nutrient-rich environment. Two kinds of white cell — and one clever trick with a scab — are why nothing has eaten you yet.
• The Heart, and What Goes Wrong With It — Two pumps in one organ, and why the muscle that pushes blood everywhere can still starve for want of it.
• Blood Vessels and the Circulation — Three kinds of vessel, three different structures — and every difference between them comes down to pressure.
• Excretion: Getting Rid of What You Made — Excretion is not the same as going to the toilet — and knowing exactly why is worth more marks than any list of organs.
• The Kidney and the Nephron — The kidney does not pick out the waste. It throws almost everything away and then takes back what it wants — and that is a far cleverer design than it sounds.
• Ultrafiltration and Selective Reabsorption — Squeeze almost everything out of the blood by pressure, then spend energy buying back exactly what you need — including every last molecule of glucose.
• ADH and the Water Balance of the Blood — One hormone, one adjustable tap at the end of the nephron — and a loop that corrects the very thing that set it off.
• Homeostasis and the Control of Body Temperature — Why the inside of you barely changes while the outside changes constantly — and exactly what the skin does about heat.
• Plant Responses, Tropisms and Auxin — A plant has no eyes, no nerves and no muscles — and still gets its roots down and its shoots up every time. This is how.
• The Nervous System, and the Two Ways a Body Sends a Message — Electrical impulses down a wire, or a chemical posted into the blood — why a body needs both, and which job each one is for.
• Synapses and the Reflex Arc — Neurones do not touch. What crosses the gap between them, why the gap is there at all, and how a hand leaves a hot pan before you know it was hot.
• The Eye — Focusing, and the Pupil Reflex — One sense organ, two adjustments: how the eye sharpens an image and how it controls the amount of light it lets in.
• The Hormones — Sources, Roles and Effects — Eight chemical messengers, three kinds of job: prepare the body for action, hold a condition steady, or run a change that takes years.
• Gas Exchange in Plants, Day and Night — Two opposite processes in one leaf, one of which never stops — and why what you can measure at the surface is only the difference between them.

Topic 3 · Reproduction and inheritance

How new organisms are made and how characteristics travel between generations — flowers, the menstrual cycle, DNA, genetic diagrams, mitosis and meiosis, mutation and natural selection.

• Sexual and Asexual Reproduction — Two ways to make a new organism — one produces copies, the other produces something that has never existed before. Why any species would want both.
• Flowers, Pollination and Fertilisation — Two completely different solutions to one problem — a plant that cannot move has to get its male gamete to another plant's female gamete.
• Seeds and Germination — What a seed needs to start growing, what it lives on before it has a single leaf — and why light is not on the list.
• The Human Reproductive Systems — Two systems built around the same problem — making gametes and bringing them together — and the hormones that switch them on.
• The Menstrual Cycle — Four hormones, two organs and one repeating question — should the uterus lining be built up, held, or let go?
• The Placenta and the Amniotic Fluid — An exchange surface with a constraint no other one has: two bloodstreams that must trade materials without ever mixing.
• DNA, Genes and Chromosomes — One molecule at four magnifications — and the pairing rule that makes it possible to copy information without understanding it.
• Protein Synthesis — The instructions cannot leave the nucleus and the factory cannot go in — so a copy is sent out. Transcription, translation, and the code that connects them.
• Alleles, Genotype and Phenotype — Two copies of every gene, and the rules that decide which one you can see — including the case where you can see both.
• Monohybrid Inheritance and Probability — A method for predicting offspring, the ratio it produces — and two honest limits on what that ratio actually tells you.
• Pedigrees and Sex Determination — Reading a family tree backwards to find genotypes nobody can see — and the one cross whose answer never changes.
• Mitosis and Meiosis — Two kinds of cell division solving two opposite problems — one that must copy exactly, and one that must not.
• Variation and Mutation — Three sources of difference between individuals — two that reshuffle what already exists, and one that makes something new.
• How Mutations Affect Proteins — One base changes. Follow the consequences — and find out why the answer is usually nothing at all.
• Natural Selection and Antibiotic Resistance — One argument in four steps — and the version of it happening in hospitals now, fast enough to watch.

Topic 4 · Ecology and the environment

Organisms in their surroundings: populations, sampling with quadrats, food chains and pyramids, the carbon and nitrogen cycles, and the specific ways humans damage ecosystems.

• Populations, Ecosystems and Sampling with Quadrats — Four nested words for where organisms live — and how to count a population you could never count in full.
• Biodiversity, Distribution and Limiting Factors — Why organisms are where they are and not somewhere else — and how to measure the variety of life in a place rather than just its quantity.
• Food Chains, Webs and Pyramids — Who eats whom, drawn three different ways — and why only one of the three can come out upside down.
• Energy Transfer Along a Food Chain — About nine tenths of the energy disappears at every step. Here is exactly where it goes — and what that means for how the world is fed.
• The Carbon and Nitrogen Cycles — The same atoms, used again and again — and the four bacteria that do the work nothing else can.
• Air Pollution and the Greenhouse Gases — Two entirely different problems that both begin with burning — one that poisons what it touches, and one that changes the energy balance of the planet.
• Global Warming and Deforestation — What a warmer planet does to living things — and why removing a forest changes the soil, the rainfall and the atmosphere all at once.
• Water Pollution and Eutrophication — Two things that should be harmless — treated sewage and plant fertiliser — and the same chain of events by which both empty a river of fish.

Topic 5 · Use of biological resources

Biology put to work — glasshouses, fertilisers, pest control, yeast and bacteria in food, fermenters, fish farming, selective breeding, genetic modification and cloning.

• Increasing Crop Yield — Everything a grower does is one of two things — remove whatever is limiting the crop, or remove whatever is competing with it.
• Yeast, Bread and Fermentation — One organism respiring without oxygen — and two industries built on the two different products it makes.
• Yoghurt and the Industrial Fermenter — Bacteria turned into a manufacturing process — and the vessel built to give them the best conditions they will ever have.
• Fish Farming and Selective Breeding — Growing food by controlling every loss of energy — and by doing deliberately what the environment does by accident.
• Genetic Engineering — Cutting a gene out of one organism and making another organism read it — and the reason that works at all.
• GM Insulin and GM Crops — The same technique used twice — once to brew a human hormone in a tank, and once to change what a field can grow.
• Micropropagation — Growing thousands of identical plants from a few cells — and why this only works because a plant cell never quite gives up its options.
• Cloning Mammals — How a lamb was built from an udder cell, what that proved about every cell in your body, and what such animals are now used for.

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