OCR GCSE Biology A key terms

The amount of substrate used up or product formed per unit time.

The return of a substance from the kidney tubules to the blood.

A substance present at the start of a chemical reaction and changed during it.

A cell or group of cells that detects a change called a stimulus.

An allele whose associated phenotype is usually seen only when two copies are present.

An allele whose associated phenotype is seen only when two copies are present in a simple dominant–recessive pattern.

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

A small, specialised blood cell that transports oxygen from the lungs to body tissues.

A sugar, such as glucose, that gives a positive result when heated with Benedict’s reagent.

The neural pathway through which impulses travel to produce a reflex response.

A rapid, automatic and involuntary response to a stimulus.

The change in direction of light as it passes between materials, such as air and a lens.

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

A nerve cell within the central nervous system that connects neurones, such as sensory and motor neurones.

The outer region of the kidney, containing Bowman’s capsules and proximal convoluted tubules.

The inner region of the kidney, into which loops of Henlé extend and through which collecting ducts pass.

A central, funnel-shaped space that collects urine and leads into the ureter.

The ability to distinguish two points that are close together as separate points; greater resolution reveals finer detail.

The cellular process that releases energy from organic substances and transfers carbon into carbon dioxide.

The action or change produced after a stimulus has been detected and information has been coordinated.

A measurement taken while a person is seated quietly before exercise, used as a comparison for later measurements.

An enzyme that cuts DNA at particular base sequences.

A layer of light-sensitive receptor cells at the back of the eye where a sharply focused image should form.

A structure in a cell where amino acids are joined together during protein synthesis.

The changes through which a fruit becomes ready for its seeds to be dispersed, often including changes in colour, texture and smell.

Something associated with an increased probability of developing a disease; exposure does not guarantee that the disease will occur.

A specialised epidermal cell on a young root whose long projection provides a large surface area for absorbing water and mineral ions from the soil.