Edexcel GCSE Combined Science key terms

An action taken to prevent or reduce the risk of harm; also called a control measure.

A solid formed in a solution during a chemical reaction because the product is insoluble.

The formation of an insoluble solid from a solution.

A reaction in which dissolved substances react to form an insoluble solid.

Testing a potential medicine on cells, tissues and animals before testing it in humans.

An interaction in which one organism, the predator, kills and eats another organism, the prey.

The force exerted per unit area of a surface, measured in pascals (Pa). Gas pressure results from particles colliding with a surface.

The coil of a transformer connected to the input alternating supply.

Energy supplied by natural resources before conversion into forms such as electricity. Total primary energy use includes resources used for transport and heating, not just electricity generation.

An organism that makes its own food, providing organic material that can support other organisms in a food chain.

A substance formed in a chemical reaction.

A hormone produced by the corpus luteum after ovulation that maintains the uterus lining and inhibits FSH and LH release.

A single-celled organism whose cell has no nucleus.

A cell without a nucleus; its chromosomal DNA lies in the cytoplasm. Bacterial cells are prokaryotic.

A particle in an atom’s nucleus with relative mass 1 and relative charge +1.

A grid showing the possible combinations of parental alleles in offspring.

A single element or compound that is not mixed with any other substance.

A square frame enclosing a known area, used to sample organisms within that area.

A measure of a person's exposure to radiation, taking account of its potential biological harm. Radiation dose is measured in sieverts (Sv).

The unwanted presence of radioactive material on or inside an object or person.

The process in which an unstable atomic nucleus emits radiation.

A radioactive substance introduced into the body so that its radiation can be detected to investigate what is happening inside the body.

A dating method that uses radioactive carbon-14 in material that was once living.

Estimating age using the radioactive decay of isotopes in suitable materials.

Movement in changing, unpredictable directions rather than along one shared path.

Selecting sampling locations by chance rather than choosing them deliberately, to reduce selection bias.

A region of a longitudinal wave where particles are farther apart than usual.