Combined Science key terms

The breakdown of large hydrocarbon molecules into smaller, more useful molecules.

The internal volume of a skull’s braincase, used to estimate brain size.

Growing different crops on the same land in successive growing seasons; including legumes can help replenish soil nitrogen.

A liquid mixture of hydrocarbons formed over millions of years from buried remains of plankton.

A substance in which aluminium oxide is dissolved during aluminium extraction, forming an electrolyte with a lower melting point than pure aluminium oxide.

The formation of solid crystals from a solution.

The rate of flow of electric charge, measured in amperes (A).

An inherited disorder of cell membranes caused by a recessive allele, resulting in thick, sticky mucus in the airways and digestive system.

Division of the cytoplasm to form two separate daughter cells.

The gel-like material inside a cell where many chemical reactions take place.

A new cell produced when a parent cell divides.

The nucleus produced by radioactive decay.

The breakdown of dead organic material by decomposers, such as bacteria and fungi.

A decrease in speed per unit time; the acceleration acts opposite to the direction of motion.

An organism, such as a bacterium or fungus, that breaks down dead organisms and waste materials.

The breakdown of dead organisms and waste materials, returning their materials to the environment.

The clearing of forests, usually on a large scale, often to use the land for another purpose.

A change in an object's shape caused by forces, such as stretching, bending or compression.

Water from which dissolved ions have been removed, used to avoid interference in chemical analysis.

An electron that is not tied to one atom or bond and can move through a structure.

A change in an enzyme’s shape, including its active site, so that its substrate no longer fits and the enzyme cannot catalyse the reaction effectively.

A short, branched extension of a neurone that receives signals.

An extension of a sensory neurone that carries electrical impulses towards its cell body.

The conversion of nitrates into nitrogen gas by denitrifying bacteria, particularly in oxygen-poor soil.

The mass per unit volume of a material: $\rho = m/V$. Its SI unit is kilograms per metre cubed, kg/m³.

The quantity measured to find out whether the independent variable has an effect.

The change directly from gas to solid, without becoming a liquid.