OCR GCSE Combined Science B key terms

Obtaining useful energy from waste, for example by burning it to generate electricity.

A source from which energy can be transferred for uses such as heating, transport or electricity generation.

A biological catalyst that speeds up a chemical reaction. Each enzyme works best within particular conditions, including a suitable temperature and pH.

The property of an enzyme that allows it to catalyse a particular reaction because its active site has a shape complementary to its substrate.

A mathematical statement that two expressions have equal values.

A situation in which the forces acting on an object are balanced, so its resultant force is zero.

The relative amounts of reactants and products present at equilibrium.

The resistance of a single resistor that could replace a combination of resistors while producing the same total current at the same supply potential difference.

An approximate value obtained using limited measurements, rounding or reasonable assumptions.

A question about whether an action and its consequences are morally right or wrong.

A cell with a nucleus containing its main genetic material. Plant and animal cells are eukaryotic.

The change of liquid water into water vapour.

A change in the inherited characteristics of a population over a number of generations.

A reactant present in a greater amount than is needed to react completely with the other reactant.

A specialised surface across which substances move between an organism and its environment.

A chemical reaction that transfers energy to the surroundings, causing their temperature to rise.

The predicted number of occurrences of an event over repeated trials, calculated as probability multiplied by the number of trials.

The power to which a number is raised. In $10^3$, the exponent is 3, meaning $10\times10\times10$.

The increase in a spring's length compared with its unstretched length, measured in metres.

A force exerted on a system by something outside that system.

The permanent loss of every living member of a species.

Estimating a value beyond the range of the collected data by extending a line or curve.

The lens through which the observer looks, which further magnifies the image produced by the objective lens.

A test result indicating that a particular allele is absent when it is actually present.

A test result indicating that a particular allele is present when it is actually absent.

A raw material used to manufacture other chemicals or materials.

The breakdown of sugars by enzymes in microorganisms such as yeast, producing ethanol and carbon dioxide without oxygen.