Netherlands VWO 4 (bovenbouw, 2e fase) Biology
Chapters: 3
1. Skills
General skills · Scientific inquiry and design · Modelling and instruments · Judging and deciding · Biology-specific skills
- Research Skills: From a Question to a Finished Project – Research is a careful way of finding an answer. You ask a clear, focused question, plan how to answer it, find information and check that each source can be trusted, collect and analyse your own data, draw a conclusion that the evidence supports, and share it while crediting every source you used.
- The Scientific Method – The scientific method is the careful way scientists find out how the world works. Observe something, ask a testable question, make a hypothesis (a clear, testable guess), test it with a fair experiment (change one variable, measure one, keep the rest the same), repeat and record data, analyse it, draw a conclusion and share it so others can check. Results that fail the test are useful too: they send you back to a new hypothesis.
- Mathematical Modelling: Using Maths to Describe the Real World – A mathematical model is an equation, graph or table that describes a real situation in a simple way. The modelling cycle: understand the real problem → choose variables and make assumptions → build a model (for example linear, quadratic or exponential) → solve and predict → check the answer against real data → improve the model or state its limits. No model is perfect; a good one is simple and close enough to be useful.
- Science, Technology and Society: How Discoveries Change Our Lives – Science finds out how nature works; technology uses that knowledge to make tools and solve problems. Society shapes science too, by asking questions, paying for research and making rules. Big changes such as the printing press, the steam engine, electricity, vaccines and the internet changed how people work, live and think. Every technology has benefits and risks. To decide wisely we look at evidence, weigh benefits against risks, ask who gains and who loses, think about ethics and the future, and use safety rules.
- Biology Thinking Skills – Biologists use special ways of thinking: observe nature closely, link form with function, see how living things depend on each other (ecology), ask how life changed over generations (evolution), and see the whole system with its linked parts.
2. Self-regulation (part 1)
Cell metabolism · Metabolism of the organism · Movement of the organism · Perception
- The Cell: Basic Unit of Life – Every living thing is made of cells. Robert Hooke first saw cells in cork in 1665. Cells are prokaryotic (no true nucleus, like bacteria) or eukaryotic (true nucleus). Plant cells have a cell wall, chloroplasts and a big vacuole; animal cells do not. Each organelle has a job. Water enters and leaves cells by osmosis. Cells make new cells by mitosis (growth) and meiosis (sex cells).
- Human Body Systems – Your body is organised in levels: cells make tissues, tissues make organs, organs make organ systems, and all systems together make you, the organism. Each system has a main job: skeletal (frame), muscular (movement), circulatory (transport), respiratory (gas exchange), digestive (food), excretory (waste), nervous and endocrine (control), immune (defence), integumentary (skin, hair, nails) and reproductive. No system works alone: during exercise the muscles, heart, lungs and nerves all change together to keep the inside of the body steady (homeostasis).
- Locomotion and Movement – Movement is a change in position of a body part; locomotion is moving the whole body from place to place. Cells move in three ways: amoeboid, ciliary and flagellar. Humans use muscular movement. Muscles are skeletal, visceral or cardiac. A skeletal muscle is made of fibres, each packed with myofibrils made of repeating sarcomeres of actin and myosin. A nerve signal releases Ca2+, myosin heads pull actin using ATP, and the sarcomere shortens (sliding filament theory). The skeleton has 206 bones. Joints can be fibrous, cartilaginous or synovial (ball and socket, hinge, pivot, gliding, saddle). Disorders include myasthenia gravis, tetany, muscular dystrophy, arthritis, osteoporosis and gout.
- Sense Organs – Sense organs let us pick up changes around us (stimuli). The eye senses light, the ear sound and balance, the nose smell, the tongue taste, and the skin touch, pressure, heat, cold and pain. Each has receptor cells that turn the stimulus into nerve signals. The signal goes along a sensory nerve to the brain or spinal cord, which sends an order to a muscle: the response.
3. Reproduction (part 1)
DNA replication · Cell life cycle
- DNA Replication: How a Cell Copies Its DNA – Before a cell divides, it makes an exact copy of its DNA so each new cell gets a full set of instructions. Helicase unzips the double helix. Each old strand is a template. DNA polymerase adds matching bases (A with T, G with C). The result is two DNA molecules, each with one old and one new strand (semi-conservative). Polymerase checks its work, so mistakes are very rare; a mistake that stays is a mutation.
- Cell Cycle and Cell Division – A cell grows, copies its DNA and splits in a fixed order called the cell cycle: interphase (G1, S, G2) and M phase. In S phase the DNA doubles (2C → 4C) but the chromosome number stays the same. Mitosis (prophase, metaphase, anaphase, telophase) and cytokinesis give two cells identical to the parent – it is an equational division used for growth and repair. Meiosis has two divisions; in meiosis I homologous chromosomes pair, cross over and separate, halving the chromosome number (2n → n). It makes four haploid cells for gametes and creates variation.