Separate Sciences (Biology, Chemistry, Physics)

Key Facts

• Each science has two papers, each worth 100 marks.
• Combined, triple science includes more detail than combined science.
• Practical skills are assessed in written exams.
• Use data skills in graphs, tables, and calculations.

Subtopics

Key Facts

• Last-minute priority: organelle functions and transport definitions.
• Higher SA:V ratio means faster diffusion.
• Prokaryotic cells (bacteria) are smaller and lack a nucleus.
• Specialised cells have adaptations that match their function.

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Key Facts

• Tissues form organs, organs form organ systems.
• Enzymes are biological catalysts with an optimum temperature and pH.
• The heart has four chambers and valves to keep blood flowing one way.
• Alveoli are surrounded by capillaries for rapid gas exchange.

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Key Facts

• Antibiotics treat bacterial infections, not viral infections.
• Monoclonal antibodies can target specific antigens.
• Overuse of antibiotics increases resistant bacteria.
• White blood cells include phagocytes and lymphocytes.

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Key Facts

• Chlorophyll absorbs light for photosynthesis.
• Respiration happens in mitochondria.
• Light intensity is the limiting factor at low light.
• Anaerobic respiration in yeast produces ethanol and carbon dioxide.

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Key Facts

• Homeostasis keeps internal conditions stable.
• Thermoregulation uses sweating, shivering, and blood flow changes.
• ADH release increases when the body is dehydrated.
• Auxin moves to the shaded side of a shoot.

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Key Facts

• Genotype is the genetic makeup; phenotype is the expressed characteristic.
• A dominant allele is expressed even with one copy.
• Homozygous means two identical alleles; heterozygous means two different alleles.
• Sex is determined by XX and XY chromosomes.

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Key Facts

• Biodiversity is higher in stable, undisturbed ecosystems.
• Human impacts include pollution, deforestation, and climate change.
• Quadrats can be used to estimate population size.
• Indicator species show pollution levels.

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Key Facts

• Period number = number of electron shells.
• Group 0 elements are noble gases and are unreactive.

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Key Facts

• Graphite conducts because of delocalised electrons.
• Diamond is hard due to a giant covalent lattice.

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Key Facts

• Percentage yield is less than 100 percent due to losses.
• Atom economy measures how much product is useful.

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Key Facts

• Oxidation is loss of electrons; reduction is gain.
• Hydrogen is produced when electrolysis competes with metal ions.

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Key Facts

• Reaction profiles show energy change and activation energy.
• Catalysts lower activation energy.

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Key Facts

• Increasing temperature increases rate but can reduce yield in exothermic systems.
• Catalysts speed up both forward and reverse reactions.

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Key Facts

• Complete combustion produces CO2 and water.
• Crude oil is separated by fractional distillation.

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Key Facts

• Flame tests: Na yellow, K lilac, Cu green.
• Pure substances have fixed melting and boiling points.

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Key Facts

• Carbon monoxide is toxic because it binds to hemoglobin.
• NOx contributes to acid rain and photochemical smog.

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Key Facts

• Alloys improve properties of metals.
• Finite resources require sustainable use.

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Key Facts

• Last-minute priority: store vs transfer language.
• Thermal energy increases when energy is dissipated.
• Energy transfers can be by heating, radiation, or mechanical work.
• Total energy in a closed system is constant.

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Key Facts

• Power in watts, energy in joules, time in seconds.
• Efficiency < 100% for real systems.

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Key Facts

• V = IR is the most common formula.
• Power = IV or I^2R or V^2/R.

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Key Facts

• Heating increases particle kinetic energy.
• Changing state does not change temperature during the change.

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Key Facts

• Alpha is most ionising, least penetrating.
• Gamma is most penetrating.

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Key Facts

• F = ma
• Acceleration changes velocity.

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• Wave speed = frequency × wavelength.
• All EM waves travel at 3 × 10^8 m/s in vacuum.

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Key Facts

• Motor effect uses current in a magnetic field.
• Generator effect induces voltage by moving through a field.

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Key Facts

• Weight depends on gravitational field strength g.
• Orbits are stable when centripetal force balances inertia.

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Key Facts

• Practicals test method and evaluation.
• State how to reduce error.

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