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An alphabetical glossary of technical terms used on the site.


A substance that has an unstable nucleus, which can fall apart and release energy.


Treatment of cancer or other diseases with radiation.


Male sheep.

Reactive oxygen species (ROS)

Chemicals like hydrogen peroxide (H2O2), superoxide (O2-) and the hydroxyl radical (-OH). Reactive oxygen species are produced naturally by the human body, but at high levels they can damage DNA.


A substance used in a laboratory to produce a reaction.


Refers to a trait that appears in an organism only if both copies of the gene are identical.


A person or animal that receives something, for example an organ or blood.

Recognition site

A specific sequence of DNA that is recognised by a restriction enzyme.


Resources able to be sustained or renewed indefinitely, either because of inexhaustible supplies or because of new growth.


The process of copying DNA within a cell.

Reporter gene

A gene coding for a protein that can be easily measured in the laboratory.


A substance left behind after a process or treatment.


A solid or liquid synthetic organic polymer used as the basis of plastics, adhesives, varnishes or other products.


The ability to withstand harmful or unfavourable conditions, such as an infectious disease.

Restriction endonuclease

An enzyme that causes a break, or cut, in both strands of DNA at a specific sequence, usually about 4-8 base pairs long. Also called a restriction enzyme.

Restriction enzyme

An enzyme that causes a break, or cut, in both strands of DNA at a specific sequence, usually about 4-8 base pairs long. Also called a restriction endonuclease.

Reverse transcription

The process of making a double-stranded DNA copy from a single-stranded RNA template.

Revolutions per minute (rpm)

A measure of centrifuge speed.

Rhesus factor

An antigen found on the surface of red blood cells. If a person does not have the antigen (Rhesus negative) they should not be given a blood transfusion from someone who does (Rhesus positive).

Rheumatic fever

A disease that causes high temperature, painful swelling of the joints, and damage to heart valves.

Rheumatic heart disease

Permanent damage to heart valves, caused by rheumatic fever.


Ribonucleic acid; generated in cells by transcription and required for the synthesis of proteins.

RNA interference (RNAi)

The process when a double-stranded RNA molecule prevents a messenger RNA (mRNA) molecule from being translated into a protein. Also called RNA silencing or RNA inactivation.

RNA polymerase

The enzyme which catalyses the formation of RNA during transcription.


Breed of sheep.


Remedy, preservative against sickness or death.

Royal Jelly

A substance made by honey bees to feed the queen bee.


Payments made for the right to use or sell an asset, sometimes an intellectual property (IP).

RPM (revolutions per minute)

A measure of centrifuge speed.


The first stomach in the digestive system of a ruminant animal, such as a cow, sheep, deer or goat.


Cud-chewing, hooved mammals, for example, sheep, cattle, deer and camels, which have a complex 3 or 4-chambered stomach.

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