Italy Secondaria di secondo grado – classe 5ª (esame di Stato) Natural sciences (liceo scientifico)
Chapters: 2
1. Chemistry and biology
Organic chemistry and biochemistry · Biotechnology
- Biomolecules – A cell is mostly water, plus four big families of carbon compounds: proteins, carbohydrates, lipids and nucleic acids. Grinding tissue in acid separates small molecules (acid-soluble pool) from big ones – proteins, polysaccharides and nucleic acids (acid-insoluble pool). Proteins are chains of amino acids folded into four levels of structure. Polysaccharides are chains of sugars; lipids are fatty acids on glycerol; nucleic acids are chains of nucleotides. Enzymes are protein catalysts that bind a substrate at the active site, lower the activation energy, and are affected by temperature, pH, substrate level and inhibitors.
- Biotechnology: Principles and Processes (Recombinant DNA Technology) – Genetic engineering means changing the genes of a living thing on purpose. We cut the gene we want with restriction enzymes (molecular scissors), paste it into a carrier DNA called a vector using DNA ligase (molecular glue), put it into a host cell, pick out the cells that took it, and grow them in big tanks (bioreactors) to collect the product. PCR makes millions of copies of a gene, and gel electrophoresis sorts DNA pieces by size.
2. Earth science
Weather and plate tectonics · Optional topics
- Distribution of Oceans and Continents: Drift, Spreading and Plates – In 1912 Alfred Wegener said all continents were once one landmass, Pangaea, surrounded by one ocean, Panthalassa, and that they drifted apart. Matching coastlines, rocks, fossils, glacier deposits and placer gold supported him, but he could not explain the force. Mapping the ocean floor showed ridges, plains and trenches; Harry Hess then proposed sea-floor spreading: new crust forms at mid-ocean ridges and old crust sinks at trenches. This led to plate tectonics: the lithosphere is broken into rigid plates that move on the soft asthenosphere and meet at divergent, convergent and transform boundaries. The Indian plate broke away from the south, moved north, and collided with Asia to raise the Himalayas.
- Ecology: Ecosystems, Matter Cycles, Energy Sources and New Materials – Ecology is the study of how living things interact with each other and with their surroundings. An ecosystem has producers (plants that make food from sunlight), consumers (animals) and decomposers (fungi and bacteria). Energy enters from the Sun and moves one way along the food chain: only about 10% passes to the next level, the rest is used or lost as heat. Matter, in contrast, is recycled in biogeochemical cycles such as the carbon, water, nitrogen and phosphorus cycles. People need energy, and the main choice is between fossil fuels (limited, add carbon dioxide) and renewable sources such as sun, wind and flowing water. New materials such as composites, smart materials, nanomaterials and plant-based plastics are designed for a job and can lower energy use and waste. Good choices balance strength, weight, safety and recycling.