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Edexcel International GCSE Biology Course Notes

This page is the main route into the revision notes. Start with the course overviews, modules, topics and summary pages below.

Overview

Modules

  • 1 The Nature and Variety of Living Organisms: This topic area establishes what life has in common and how the main organism groups differ. It provides the classification and organism-feature groundwork that later ecology, nutrition and genetics pages depend on.
  • 2 Structure and Functions in Living Organisms: This topic area is the structural core of the course. It connects cells, molecules and movement across membranes to whole-organism systems such as transport, gas exchange, excretion and coordination.
  • 3 Reproduction and Inheritance: This topic area explains how organisms reproduce, how genetic information is carried and how inherited patterns are represented. It bridges cell division ideas from earlier work to variation and heredity.
  • 4 Ecology and the Environment: This topic area moves outward from organisms to ecosystems. It connects populations, feeding relationships, material cycles and human environmental impact into one ecological picture.
  • 5 Use of Biological Resources: This topic area applies earlier biology to agriculture, breeding and biotechnology. It is where the course becomes most overtly applied, drawing on ecology, inheritance and cell-level knowledge together.

Topics

1 The Nature and Variety of Living Organisms

  • 1a Characteristics of Living Organisms: The idea of life in this course is built from a shared set of processes. These characteristics are useful because they give one framework for comparing organisms that look very different on the surface.
  • 1b Variety of Living Organisms: Organisms are grouped here by their shared cell features, modes of nutrition and overall body plan. The important comparisons are between eukaryotes, prokaryotes and viruses, and between the main eukaryotic groups themselves.

2 Structure and Functions in Living Organisms

  • 2a Level of Organisation: Biology moves from the smallest working parts of cells to whole systems. This hierarchy matters because each level depends on the successful co-operation of the level below it.
  • 2b Cell Structure: Cell structure links what cells contain to what they can do. In this course the key comparisons are between plant and animal cells, and between unspecialised cells, specialised cells and stem cells.
  • 2c Biological Molecules: Biological molecules supply energy, build structures and allow reactions to happen at useful rates. The main focus here is the relationship between basic chemical building blocks, food tests and enzyme function.
  • 2d Movement of Substances into and out of Cells: Exchange across membranes is one of the big unifying ideas in biology. The key comparisons are between passive movement down gradients and active movement that uses energy.
  • 2e Nutrition: Nutrition in this course brings plant food production and human feeding into one topic. The link between them is that both depend on molecules being made, broken down and transported where they are needed.
  • 2f Respiration: Respiration is how cells release usable energy from food. The main distinctions here are between aerobic and anaerobic pathways and between energy release in living tissue and what you can measure in practical work.
  • 2g Gas Exchange: Gas exchange links diffusion to whole-organism survival. Plants need carbon dioxide and oxygen moving in opposite directions at different times, while humans need a ventilated surface that keeps diffusion rapid.
  • 2h Transport: Transport systems solve the problem that large multicellular organisms cannot rely on diffusion alone. In this topic the course compares plant transport in xylem and phloem with animal transport in blood and the circulation.
  • 2i Excretion: Excretion is about removing waste products of metabolism and keeping water and ion balance under control. In this course that means linking plant waste gases with the much more detailed kidney story in humans.
  • 2j Co-ordination and Response: Co-ordination links stimulus detection to effective response. The topic includes both plant responses and the faster nervous or hormonal control systems used in humans to maintain stable internal conditions.

3 Reproduction and Inheritance

  • 3a Reproduction: Reproduction combines the production of new individuals with the early stages of development. The topic brings together plant reproduction, human reproduction, germination and the contrast between sexual and asexual methods.
  • 3b Inheritance: Inheritance explains how information stored in DNA influences phenotype and how that information passes between generations. The topic links molecular ideas to genetic crosses, cell division, variation, mutation and natural selection.

4 Ecology and the Environment

  • 4a The Organism in the Environment: Ecology begins by naming the levels at which organisms interact with their surroundings. It then moves into ways of measuring populations and biodiversity in real habitats.
  • 4b Feeding Relationships: Feeding relationships show how matter and energy move through ecosystems. The main emphasis is on trophic levels, the meaning of food chains and food webs, and why only a small fraction of energy is transferred onwards.
  • 4c Cycles within Ecosystems: Matter is continually recycled through ecosystems rather than used once and lost. The important cycles here are the carbon cycle and the nitrogen cycle.
  • 4d Human Influences on the Environment: Human activity can alter ecosystems by changing gases, nutrients, water quality and land cover. The topic is mainly about tracing cause and effect from human action to biological consequence.

5 Use of Biological Resources

  • 5a Food Production: Food production applies biology to agriculture, fermentation and fish farming. The common theme is using living systems more efficiently while controlling the conditions that limit yield or survival.
  • 5b Selective Breeding: Selective breeding uses inheritance knowledge to increase the frequency of desirable characteristics in plants and animals. The benefits are clear, but so are the genetic risks if variation is reduced too far.
  • 5c Genetic Modification (Genetic Engineering): Genetic modification changes an organism by inserting a gene from another source. The key ideas are the molecular tools, the role of vectors and the practical uses of modified organisms.
  • 5d Cloning: Cloning produces genetically identical copies. In this course the two main contexts are micropropagation in plants and cloning mammals by transferring a diploid nucleus into an enucleated egg cell.

Practicals

Syntheses