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An alphabetical glossary of technical terms used on the site.


A breeding method for introgressing a desirable trait into an elite breeding population. In traditional backcrossing, successive generations of apples with the trait of interest are crossed with the same high-quality parent. In modified backcrossing, a different high-quality parent is used at each generation.


Single-celled microorganisms that lack a nucleus.

Bacterial artificial chromosome (BACs)

A bacterial vector for cloning DNA. BACs can accommodate longer stretches of DNA than plasmid vectors.


DNA is made up of four bases: adenine (A), cytosine (C), guanine (G) and thymine (T). In RNA, the base uracil (U) replaces thymine.

Base pairs

The unit of double-stranded DNA. Bases pair up so that A joins with T and C joins with G.


A type of sugar molecule.


An error caused by favouring some outcomes more than others.

Binary fission

A form of asexual reproduction and cell division used by all prokaryotes. It is the process by which a single cell after replicating its genetic material, divides into two nearly equal sized daughter cells.


A substance that has an effect on living tissue.


A method used to determine the concentration or properties of a substance in a living cell or organism.


The use of a living organism, or the product of a living organism to control the population size of another organism, usually a pest.


The ability of a substance to be broken down physically and/or chemically by microorganisms. For example, many chemicals, food scraps, cotton, wool and paper are bio-degradable; plastics and polyester generally are not.


An alternative to diesel fuel that is made from renewable resources, such as animal fats or vegetable oils.


The variety of living organisms, including plants, animals and microorganisms, living in a particular area.


A process of growing microorganisms to produce a substance, such as an enzyme or chemical.


A conglomeration of bacterial cells on a surface.


A fuel made from biological materials, (i.e. biomass) such as wood, fish oil, vegetable oil or animal waste.


The use of information technology and computers to capture, record and interpret complex biological data, for example DNA sequences and patterns of gene expression.


Using a particle bombardment system, like a gene gun, to deliver DNA into a cell.

Biological oxygen demand (BOD)

The amount of oxygen needed by the organisms living in an aquatic environment.

Biologically active

A substance that has an effect on living tissue.


Light emitted from an organism as a result of a biochemical reaction.


Plant material or agricultural waste, which can be turned into a biofuel.


Using biological science for medical developments.


A chemical compound that naturally occurs in living organisms, which consist mainly of carbon and hydrogen, nitrogen, oxygen, phosphorus and sulfur.


A pesticide that is biological in origin. Examples include viruses, bacteria or natural plant chemicals.


Producing pharmaceuticals in plants or livestock, a process that may involve genetic modification.


Any large molecule in an organism that is made up of a repeating number of smaller components. Examples include proteins (made up of amino acids), starch and cellulose (made up of sugars) and DNA (made up of nucleic acids).


A sample of tissue taken from a living patient for diagnostic tests.


A vessel for growing live organisms or cells, which can be used for the production of substances such as pharmaceuticals, antibodies or vaccines, or for breaking down organic waste.


The use of organisms, usually microorganisms, to break down pollutants in soil, air or groundwater.


The protection of a geographical area from invasion by an unwanted organism.


The production of a new molecule by a living organism.


Having two shells. Bivalve molluscs, such as mussels, have two symmetrical shells that enclose their flesh.


An early embryo, about 4–7 days after fertilisation, which consists of a hollow ball of cells filled with fluid.

Bovine spongiform encephalopathy

Bovine spongiform encephalopathy (BSE) or mad cow disease is a fatal disease that affects cattle. It causes the animals to stagger and become agitated.


A genus of plants in the mustard family (Brassicaceae). The members of the genus may be collectively known either as cabbages, or as mustards.

Breeding value

The value of an individual plant or animal as a genetic parent. Breeding values are a measure of the ability of an individual to pass on desirable traits to its progeny.

Broadcast spawning

A method of reproduction used by many marine animals in which unfertilised eggs and sperm are released into the water at the same time.


A group of mature adult fish or shellfish that are kept separate and used for breeding.


A solution that is added to chemical reactions in the laboratory to prevent changes in pH.


Also called incidental catch. The harvest of fish or shellfish other than the species for which the fishing gear was set.

Byssal threads

Strong fibres made from protein that are used by mussels and other bivalves to attach to rocks and other surfaces. Also known as the mussel’s ‘beard’.

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