OCR GCSE Combined Science B key terms

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

Information collected through observations or measurements.

One of the new cells produced when a parent cell divides.

The nucleus remaining after a parent nucleus has emitted radiation.

A decrease in speed; for motion in a chosen positive direction, this corresponds to negative acceleration.

A way of writing a number using place value, with a decimal point separating whole-number places from tenths, hundredths and smaller places.

The number of digits written after the decimal point.

An organism, such as a bacterium or fungus, that obtains nutrients by breaking down dead organisms or organic waste.

A change in an object's shape or size caused by applied forces.

A unit of angular measure; one complete turn is $360^\circ$.

An electron that is not attached to one particular atom and can move throughout a structure.

A change in an enzyme’s shape that prevents its substrate fitting the active site, so the enzyme can no longer catalyse the reaction.

Mass per unit volume: how much mass is packed into a given volume.

The variable measured in an investigation, such as water uptake rate.

Removing dissolved salts from salt water to obtain fresh water.

A model that describes or summarises a pattern or phenomenon, without necessarily explaining its cause.

Keeping a plant in darkness so that stored starch is used up, providing leaves without starch at the start of an investigation.

A molecule containing two atoms, such as $\mathrm{Cl_2}$.

A tool that identifies an organism through a sequence of choices between two alternative descriptions of its features.

The process by which a cell becomes specialised to carry out a particular function.

The net movement of particles from a region of higher concentration to a region of lower concentration, down a concentration gradient.

The breakdown of large food molecules into smaller molecules that can be absorbed.

An acid solution containing a relatively small amount of acid in a given volume of solution.

A component that allows substantial current in one direction but has very high resistance in the reverse direction.

Having two sets of chromosomes in the nucleus, one inherited from each parent.

An electric current that flows in one direction.

A relationship in which one quantity is a constant multiple of another: $A\propto B$ means $A=kB$, where $k$ is constant.