OCR GCSE Combined Science B key terms

The passage of a wave through a material.

The loss of water vapour from a plant's leaves.

The movement of water and dissolved mineral ions through xylem from the roots towards the leaves.

A wave in which the vibrations are perpendicular to the direction of wave travel.

A device with blades that is turned by moving air, water or steam.

A condition in which the pancreas stops producing insulin, so blood glucose is not properly controlled.

A condition in which body cells respond inadequately to insulin, or the pancreas produces insufficient insulin, so blood glucose is not properly controlled.

Use of a contraceptive method in everyday life, including mistakes such as missed pills or incorrect condom use.

The fine detail of a cell's sub-cellular structures, revealed by electron microscopy.

An indication of the doubt associated with a measurement; repeated readings can help reveal its likely spread.

Acceleration for which velocity changes by the same amount in each equal time interval.

An agreed measurement standard used to express a quantity, such as the metre for length.

A symbol or word placed before a unit to indicate a power-of-ten multiple or fraction of that unit.

A mixture of indicators that changes colour across a range of pH values, allowing pH to be estimated using a colour chart.

A waste substance formed in the liver when excess amino acids are broken down, carried to the kidneys and removed in urine.

Giving a vaccine containing a safe form of a pathogen or its antigens to stimulate an immune response and form memory cells.

The extent to which a method measures what it is intended to measure and allows the investigation to answer its question.

A structure that prevents blood flowing backwards.

A letter or symbol representing a quantity whose value can vary or be unknown.

A component whose resistance can be adjusted to change the current in a circuit.

A different version of a gene; also called a genetic variant or allele.

An organism that carries a pathogen from one host to another.

A blood vessel that carries blood towards the heart.

Speed in a specified direction. Constant velocity requires both constant speed and constant direction.

A graph showing how an object's velocity changes with time. Its gradient gives acceleration and its signed area gives displacement.

A lower chamber of the heart that pumps blood out into an artery.

Workable in practice: technically possible, affordable and able to produce something useful.

An instrument that measures potential difference and is connected in parallel across the component being investigated.