IGCSE Biology

15:02 Topic 1 Characteristics & Classification A car moves. It uses fuel, gives off waste gases, and responds when you turn the wheel. So is a car alive? No — and biology can tell you exactly why. Living… 13:41 Topic 2 Cell Structure Zoom in on a leaf, on your skin, on a drop of pond water — and you find the same thing everywhere: cells. A cell is the smallest thing that can carry out all… 7:44 Topic 3 Movement Into and Out of Cells A cell is surrounded by a membrane, and it must keep trading with the world outside. Oxygen has to get in. Carbon dioxide has to get out. Water moves both… 5:26 Topic 4 Biological Molecules Bread, meat, oil, your own muscles — all of them are built from just a handful of chemical elements. And the large molecules in your food are not really large… 5:54 Topic 5 Enzymes Every second, thousands of chemical reactions are running inside you. Left to themselves, almost all of them would be far too slow to keep you alive. What… 7:36 Topic 6 Photosynthesis A plant cannot hunt and it cannot move. So it builds its own food out of almost nothing: a gas from the air, water from the soil, and light. Every meal you… 15:52 Topic 7 Human Nutrition The food on your plate is made of molecules far too big to enter your blood. So your body takes it apart — first by crushing it, then by cutting the molecules… 5:54 Topic 8 Transport in Plants A tall tree lifts water a hundred metres into the air, every day, with no pump and no moving parts. It does it using nothing but evaporation from its leaves… 8:21 Topic 9 Transport in Animals Your heart beats about a hundred thousand times a day, and it has never once stopped to rest. It is not really one pump — it is two, side by side, sharing a… 6:05 Topic 10 Diseases and Immunity Right now, your body is being tested by microbes — on your skin, in the air you breathe, in the food you eat. Almost all of them never get in. And when one… 5:54 Topic 11 Gas Exchange in Humans Your lungs would cover half a tennis court if you spread them flat. They are not one big bag — they are millions of tiny sacs, and that is the whole point.… 5:00 Topic 12 Respiration Here is the single most common mix-up in IGCSE Biology. Respiration is not breathing. Breathing is moving air in and out of your lungs — a physical action… 4:50 Topic 13 Excretion in Humans Your kidneys filter your entire blood supply about thirty times a day. But here is the clever part: they do not pick out the rubbish. They throw almost… 18:13 Topic 14 Coordination and Response Touch something hot and your hand is already moving before you feel the pain. That is one of your two control systems — the fast one, made of nerves. The other… 4:37 Topic 15 Drugs and Antibiotics Ask a doctor for antibiotics when you have a cold and they will say no. Not because they are being difficult — because it genuinely would not work, and because… 10:39 Topic 16 Reproduction There are only two ways to make a new organism, and they trade off against each other. One is fast, needs a single parent, and makes perfect copies. The other… 8:11 Topic 17 Inheritance Two brown-eyed parents can have a blue-eyed child. That is not a mistake, and it is not a surprise once you can read genotypes. By the end of this lesson you… 7:35 Topic 18 Variation and selection In the year eighteen hundred, almost every peppered moth in England was pale. Fifty years later, in the smoky cities, almost every one was black. No moth… 8:11 Topic 19 Organisms and their Environment An African savanna. A coral reef. They look nothing alike, but they run on the same rule. Every living thing here is joined to the others by feeding. Energy… 7:43 Topic 20 Human influences on ecosystems A farmer spreads fertiliser on a field. Ordinary, useful work. Two kilometres away there is a river, full of fish. Three weeks later those fish are floating… 7:59 Topic 21 Biotechnology and genetic modification Steel tanks, warm and gently stirred. Inside tanks like these, billions of living microbes are working for us — making penicillin, a protein food called…