Edexcel GCSE Combined Science key terms

The angle between an incoming ray and the normal at a boundary.

The angle between a transmitted, refracted ray and the normal at a boundary.

A negatively charged ion that moves towards the anode during electrolysis.

The positive electrode in electrolysis, where electrons are lost.

Solid impurities that collect beneath the anode during electrolytic purification of a metal.

A medicine that kills bacteria or inhibits their growth by interfering with bacterial cell processes.

An inherited ability of bacteria to survive an antibiotic that would kill susceptible bacteria or prevent their reproduction.

A protein produced by lymphocytes that binds to a particular antigen because its binding site has a complementary shape.

A molecule, often on a pathogen’s surface, that is recognised by the immune system and can trigger a specific immune response.

Dissolved in water, indicated by the state symbol $(aq)$ in a chemical equation.

A solution in which water is the solvent, shown by (aq) in a chemical equation.

An object made or modified by humans or their ancestors, such as a stone tool.

A blood vessel that carries blood away from the heart.

Reproduction involving one parent, producing genetically identical offspring unless mutations occur.

Medical treatment used to help people conceive, including IVF.

The build-up of fatty plaques in artery walls, which narrows the space through which blood flows.

The mixture of gases surrounding the Earth.

The smallest particle of an element that retains that element's identity. It contains a nucleus surrounded by electrons.

A representation used to explain observations and make predictions about how atoms behave.

The number of protons in a nucleus, represented by $Z$. It determines which element the atom belongs to.

An upper chamber of the heart that receives blood from veins and passes it into a ventricle.

The total distance travelled divided by the total time taken, including any stops.

The number of particles per mole, represented by $N_A$. For these GCSE calculations, use $N_A = 6.02 \times 10^{23}\ \text{mol}^{-1}$.

A long extension of a neurone that carries electrical impulses away from its cell body.

Ionising radiation present around us in the environment, even when no deliberate radioactive source is nearby.

A biological extraction method in which bacteria help produce a solution containing metal ions from an ore; also called bioleaching.

A chemical equation with the same number of atoms of each element on both sides.