Combined ScienceQ&A by dot point

The cell cycle and mitosis producing two genetically identical cells, the role of mitosis in growth, repair and asexual reproduction, stem cells in embryos, adult tissue and plant meristems, and the use of stem cells in medicine and the ethics involved.

Eukaryotic and prokaryotic cells, the function of sub-cellular structures (nucleus, mitochondria, ribosomes, chloroplasts, cell wall, vacuole, plasmids), light and electron microscopy, the magnification equation, and the use of standard form and SI units for cell sizes.

Enzymes as biological catalysts, the lock and key model and the active site, the effect of temperature, pH and substrate concentration on enzyme activity, denaturing, and the breakdown of carbohydrates, proteins and lipids by digestive enzymes.

Aerobic and anaerobic respiration and their word equations, photosynthesis as an endothermic reaction, the limiting factors of light intensity, carbon dioxide concentration and temperature, and the inverse square law relating light intensity to distance.

Diffusion, osmosis and active transport as ways substances move across membranes, the factors affecting the rate of diffusion, surface area to volume ratio, and the adaptations of exchange surfaces such as alveoli, villi and root hair cells.

The human circulatory system (heart, blood vessels and blood), the double circulation, the structure of arteries, veins and capillaries, the components and roles of blood, and transport in plants by xylem and phloem with transpiration and translocation.

Levels of organisation in an ecosystem, biotic and abiotic factors, interdependence and competition, the carbon cycle and the nitrogen cycle, decomposition, biodiversity, and human impacts on the environment.

DNA, genes and chromosomes, sexual and asexual reproduction, meiosis producing genetically varied gametes, dominant and recessive alleles, genotype and phenotype, Punnett squares and inheritance ratios, and inherited disorders.

Communicable and non-communicable diseases, types of pathogen and how they spread, the body's defences and the immune system, vaccination, antibiotics and the development and testing of new drugs.

The endocrine system and the role of hormones, the control of blood glucose by insulin and glucagon, type 1 and type 2 diabetes, the reproductive hormones and the menstrual cycle, and a comparison of nervous and hormonal control.

The structure of the nervous system, the reflex arc and the role of synapses, receptors and effectors, the principle of homeostasis, and the control of body temperature, blood glucose and water as examples of negative feedback.

Genetic and environmental causes of variation, mutation, evolution by natural selection, evidence from fossils and antibiotic resistance, selective breeding, genetic engineering, and the work of Darwin.

The structure of the atom (protons, neutrons and electrons), relative charges and masses, atomic number and mass number, isotopes, electronic structure, and the development of the model of the atom from Dalton to the nuclear model.

Ionic bonding and the formation of ions, covalent bonding and shared electron pairs, metallic bonding and the sea of delocalised electrons, dot and cross diagrams, and how the type of bonding is decided by the elements involved.

The particle model of solids, liquids and gases, the arrangement and movement of particles in each state, changes of state and their names, the energy changes involved, and the limitations of the simple particle model.

The properties of ionic compounds, simple molecular substances, giant covalent structures (diamond, graphite, graphene) and metals, related to their structure and bonding, and the properties of nanoparticles and polymers.

Elements, compounds and mixtures, the difference between mixtures and compounds, purity and formulations, and the separation techniques of filtration, crystallisation, simple and fractional distillation and chromatography.

The arrangement of the periodic table by atomic number into groups and periods, the development by Mendeleev, the link between group number and outer electrons, and the properties and trends of Group 1, Group 7 and Group 0 elements.

Electrolysis of molten ionic compounds and aqueous solutions, the movement of ions to the electrodes, the products at the cathode and anode, the rules for aqueous electrolysis, and the use of electrolysis to extract reactive metals.

Exothermic and endothermic reactions and everyday examples, temperature changes in reactions, reaction profile diagrams, activation energy, and the energy change in terms of breaking and making bonds.

Tests for the common gases (hydrogen, oxygen, carbon dioxide and chlorine), flame tests for metal ions, tests for carbonate, halide and sulfate ions, and the use of these tests to identify an unknown compound.

The reactivity series of metals, displacement reactions of metals and their salts, the reactions of metals with water and acids, the extraction of metals by reduction with carbon, and writing ionic and half equations.

The factors affecting the rate of reaction (concentration, temperature, surface area, catalysts) and collision theory, the mole and concentration calculations, reversible reactions and dynamic equilibrium, Le Chatelier's principle, and the Haber process.

Word and balanced symbol equations, conservation of mass, the reactions of acids with metals, bases and carbonates, neutralisation, the pH scale, and oxidation and reduction in terms of oxygen and electrons.

Circuit symbols, current as the flow of charge, potential difference and resistance, the equation V equals I times R, the I-V characteristics of components, and the rules for series and parallel circuits.

The electromagnetic spectrum as a continuous range of transverse waves travelling at the speed of light in a vacuum, the order from radio waves to gamma rays, the uses of each region, and the dangers of the higher-energy waves.

Permanent and induced magnets, magnetic fields and field lines, the magnetic field around a current-carrying wire and a solenoid, electromagnets and their uses, and the motor effect with the factors affecting the force.

The definition of half-life, calculating the remaining activity after a number of half-lives, the uses of radioactive sources (medical tracers, treatment and dating), the difference between irradiation and contamination, and how to reduce the risks of radiation.

The structure of the atom and isotopes, radioactive decay as a random process, the nature and properties of alpha, beta and gamma radiation, their penetrating and ionising power, and nuclear equations for alpha and beta decay.

Transverse and longitudinal waves, the meaning of amplitude, wavelength, frequency and period, the wave speed equation, the relationship between frequency and period, and the reflection and refraction of waves.

Energy stores and transfers, the conservation of energy, work done as energy transferred by a force, kinetic and gravitational potential energy, and the calculation of these energy stores.

Scalar and vector quantities, distance, displacement, speed, velocity and acceleration, distance-time and velocity-time graphs, the equations of motion, and the meaning of gradient and area under a graph.

The national grid and the role of step-up and step-down transformers, electrical power and energy calculations, the comparison of renewable and non-renewable energy resources, and the environmental and practical trade-offs involved.

Newton's three laws of motion, resultant force, weight and mass, the equation force equals mass times acceleration, momentum and its conservation, and stopping distance as the sum of thinking and braking distances.

Density and its calculation, the particle model of the three states, internal energy and changes of state, specific heat capacity and specific latent heat, and the link between gas temperature and pressure.

Power as the rate of energy transfer, the equations for power, efficiency as the fraction of energy transferred usefully, the dissipation of energy, and ways to reduce unwanted energy transfers such as lubrication and insulation.