Combined Science key terms

A positively charged particle used to probe atomic structure in the gold-foil scattering experiment.

An electric current that repeatedly reverses direction.

An electric current in which the movement of charge repeatedly changes direction.

A potential difference whose polarity repeatedly reverses: each terminal is alternately positive and negative relative to the other.

A potential difference whose polarity repeatedly reverses.

A tiny air sac in a mammalian lung where gases are exchanged between air and blood.

A small molecule that can be joined to other amino acids to make a protein.

A meter that measures electric current and is connected in series with the components being tested.

The unit of electric current. A current of one ampere means one coulomb of charge passes a point each second.

The maximum displacement of a point on a wave from its undisturbed position. Amplitude is measured in metres (m).

A carbohydrase enzyme that breaks down starch into sugars.

The breakdown of organic matter by microorganisms without oxygen.

Respiration that transfers energy from glucose without using oxygen. In muscle cells, it produces lactic acid.

The angle between the incoming ray and the normal.

The angle between the transmitted, refracted ray and the normal.

A salt containing no water of crystallisation.

A negatively charged ion, formed when an atom gains electrons.

The positive electrode in electrolysis, towards which negative ions move.

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

A result that does not fit the pattern of the other results.

A substance that kills bacteria or inhibits their growth and reproduction.

The ability of bacteria to survive an antibiotic that would normally kill them.

A protein produced by white blood cells that binds to an antigen with a complementary shape, helping the body destroy the pathogen.

A molecule on a pathogen’s surface to which a specific antibody can bind.

A medicine used to control HIV infection by reducing the virus's reproduction.

A protein produced by white blood cells that neutralises a toxin produced by a pathogen.

Describes a substance dissolved in water.