AQA GCSE Combined Science Trilogy key terms

The process by which plants use light energy to make glucose from carbon dioxide and water.

A change in which no new substance forms. When a change of state is reversed, the material recovers its original properties.

A change that does not produce new substances, such as dissolving, evaporating or separating the components of a mixture.

A method of extracting metals using plants to absorb metal compounds, followed by harvesting and burning the plants and processing the ash.

An endocrine gland at the base of the brain that releases several hormones, including hormones that stimulate other endocrine glands.

A treatment resembling the medicine being tested but containing none of its active drug, used as a comparison in a trial.

Small organisms that drift in water, including microscopic aquatic plants and animals.

The liquid component of blood, mainly water, which transports dissolved substances and suspends blood cells and platelets.

A small circular piece of DNA found in bacterial cells, separate from their main chromosome; it can be used as a vector.

A small cell fragment involved in blood clotting.

A small compass whose magnetic needle aligns with the magnetic field; its north-seeking end indicates the field direction.

An early model of the atom consisting of a ball of positive charge with negative electrons embedded throughout it.

The addition of harmful substances to the environment.

A charged group of atoms that acts as a single ion, such as nitrate, $\mathrm{NO_3^-}$, or sulfate, $\mathrm{SO_4^{2-}}$.

Having extra fingers or toes; the inherited form studied here is caused by a dominant allele.

A substance consisting of very large molecules in which a group of atoms repeats many times, joined by covalent bonds.

All the organisms of one species living in a particular habitat.

The relative amounts of reactants and products present in a reaction mixture at equilibrium.

A particle formed when an atom loses one or more electrons, leaving more protons than electrons.

A positively charged particle formed when a metal atom loses outer-shell electrons.

An observable change indicating that the substance being tested for has been detected.

Water that is safe to drink, with sufficiently low levels of harmful microbes and dissolved substances. It is not necessarily chemically pure.

The energy transferred per unit charge between two points, measured in volts (V).

An apparatus that measures water uptake by a leafy shoot, allowing transpiration rate to be estimated.

The rate of energy transfer, measured in watts (W). One watt is one joule transferred per second.

The stated power of an appliance when it operates under its intended conditions.

An insoluble solid formed during a reaction in a solution.