Biology key terms

A comparison of two quantities, such as the estimated area of the cytoplasm compared with that of the nucleus.

The scientific reason for carrying out an investigation in a particular way, including what is being tested and why.

The return of a substance from fluid in the kidney to the blood.

A substance that is used up in a chemical reaction.

The time between a stimulus occurring and a person responding to it.

A substance added to a sample to produce a chemical reaction that can reveal whether another substance is present.

The actual physical size of the object being viewed.

A cell that detects a stimulus.

Describes an allele that is expressed in the phenotype only when two copies are present and no dominant allele is present.

An allele that is expressed in the phenotype only when two copies are present and no dominant allele is present.

DNA made by artificially joining genetic material from different sources.

The period after exercise during which pulse or breathing rate moves back towards its resting value.

How quickly pulse rate falls back towards its resting value after exercise.

The time from the end of exercise until a measured rate returns to its resting level.

The processing of waste materials so that they can be used again as resources.

A biconcave blood cell containing haemoglobin and specialised to transport oxygen.

A blood cell that transports oxygen using haemoglobin.

A sugar, such as glucose, lactose or maltose, that gives a positive result with Benedict’s solution when heated.

A group whose measurements provide the values used for comparison on a percentile chart.

A rapid, involuntary response to a stimulus.

A rapid, automatic response to a stimulus that does not require conscious thought.

The pathway taken by nerve impulses to produce a reflex action.

A rapid, automatic response to a stimulus that occurs without conscious control.

Planting trees to restore woodland or forest.

The bending of light as it passes between materials; lenses use this to change where light rays come to a focus.

The growth or replacement of damaged cells or tissues so that some function may be restored.

An immune response in which the recipient’s body recognises a transplanted organ as foreign and attacks it.