Biotechnology Glossary



A polysaccharide extracted from seaweed and one of the two principal components of agar growth media; used for the electrophoresis of DNA and other large molecules.
See Electrophoresis


A laboratory technique for separating mixtures; used for preparation, purification and analyses.


The receptive state of bacteria that are able to undergo transformation. This may occur naturally or induced in a laboratory.


The transfer of genetic material between two bacteria that are in direct contact. One of three horizontal gene transfer processes.
See also Transduction, Transfection, Transformation


Abbreviation for deoxyribonucleic acid. A chain of nucleotides that carry genetic information for the growth, development and function of living organisms and many viruses. Most DNA molecules consist of two coiled strands that form a double helix.

DNA Electrophoresis

See Nucleic Acid Electrophoresis

DNA Fragmentation

See Restriction Digest

DNA Purification

See Ethanol Precipitation, Plasmid DNA Purification

DNA Quantification

Procedure performed to determine the purity and concentrations of DNA or RNA present in a mixture.

DNA Replication

The creation or biosynthesis of DNA in vivo.
See DNA Synthesis, Polymerase Chain Reaction

DNA Synthesis

The natural or artificial creation of deoxyribonucleic acid (DNA) molecules.


A laboratory technique that uses an electrical current to separate the components of substances based on size.


Abbreviation for enzyme-linked immunosorbent assay. A test that uses antibodies and color change to identify a substance.

Ethanol Precipitation

A common method for concentrating and purifying nucleic acids (DNA or RNA).

Gel Electrophoresis

A method to separate and analyze macromolecules based on size and electrical charge. Used to separate proteins, mixed populations of DNA and RNA fragments (by length), and to estimate the sizes of DNA and RNA fragments.

Gene Synthesis

The process of creating artificial gene sequences.


See Plasmid DNA Purification

Horseradish Peroxidase

Abbreviated as HRP. A glycoprotein that can be conjugated to labeled molecules to produce a detectable and quantifiable signal. Also commonly used in ELISA and immunohistochemistry techniques.


See Plasmid DNA Purification


See Plasmid DNA Purification


See Plasmid DNA Purification


See Plasmid DNA Purification


See Plasmid DNA Purification

Northern Blot

Also called RNA blot. Used to study gene expression by detecting RNA/isolated mRNA. Electrophoresis is used to separate RNA samples by size, and further detection is performed using a hybridization probe.

Nucleic Acid Electrophoresis

An analytical technique used to separate DNA or RNA fragments by size and reactivity. Both agarose (for relatively long DNA molecules) and polyacrylamide (for short DNA) gels may be used. Results are visualized using a fluorescent dye that specifically binds to the nucleic acid and reveals bands corresponding to different nucleic acid molecules populations with different molecular weights.


See Polymerase Chain Reaction


Small DNA molecules inside cells that can replicate independently and are not part of the chromosomal DNA. Plasmids in nature may carry genes like antibiotic resistance; artificial plasmids are used in molecular cloning as vectors that drive the replication of recombinant DNA sequences within host organisms, a process called transformation. See Transformation

Plasmid DNA Purification

Typically performed using commercial kits; named by the bacterial culture volume and corresponding plasmid yield.

  • • Microprep volume: 0.5 to 1.5mL; yield: up to 6µg
  • • Miniprep volume: 1 to 5mL; yield: up to 60µg
  • • Midiprep volume: 25 to 100mL; yield: up to 150µg
  • • Maxiprep volume: 100 to 500mL; yield: up to 750µg
  • • Megaprep volume: 500mL to 2.5L; yield: up to 2.5mg
  • • Gigaprep volume: 2.5 to 5L; yield: up to 10mg

Polymerase Chain Reaction

Also called PCR. A technique used to make multiple copies of small pieces of DNA for further testing; used for DNA cloning and sequencing, gene cloning and manipulation, gene mutagenesis; functional analysis of genes; hereditary disease diagnosis, genetic “fingerprints” for forensic and parentage testing; and detecting infectious disease pathogens.

Restriction Digest

Also called DNA fragmentation. A procedure to prepare DNA for analysis; an enzymatic technique that cleaves DNA molecules at specific sites.


Abbreviation for ribonucleic acid. A polymeric molecule that performs gene coding, decoding, regulation, and expression. Typically a single-strand of material that is folded onto itself.

Southern Blot

Used to detect specific DNA sequences in DNA samples. DNA fragments are separated by electrophoresis, applied to a filter membrane and further tested using probe hybridization.

Western Blot

Also called protein immunoblot. Widely used to detect specific proteins in a sample of tissue homogenate or extract. Denatured samples are separated by gel electrophoresis and then exposed sequentially to a primary antibody and a secondary (labelled) antibody.

RNA Electrophoresis

See Nucleic Acid Electrophoresis


The quantitative measurement of the reflection or transmission properties of a material as a function of wavelength, typically in the visible, near-ultraviolet, or near-infrared light spectra. May be used to measure enzyme activity, protein concentrations, enzymatic kinetic constants, and ligand binding reactions.


Abbreviation for sodium dodecyl sulfate polyacrylamide gel electrophoresis. A variant of electrophoresis with polyacrylamide gel; used to analyze proteins and short DNA segments.

Streak Plates for Bacterial Culture

A method used to produce individual colonies of bacteria for subsequent study or testing. Agar plates are inoculated with a sample; the sample is then spread out so that single bacteria will grow in isolated colonies.

Taq Polymerase

A heat-stable enzyme that assembles a new DNA strand from free nucleotides; uses single-stranded DNA as a template and DNA oligonucleotides to initiate synthesis.

Thermal Cycler

Device used to help perform PCR by exposing the samples to cycles of heating and cooling.


The injection of foreign DNA into a bacterium by introducing a bacteriophage virus. One of three horizontal gene transfer processes.
See also Conjugation, Transfection, Transformation


The insertion of new genetic material into nonbacterial (animal and plant) cells.
See also Conjugation, Transduction, Transformation


Genetic changes to a cell made by direct uptake and incorporation (through the cell membrane) of exogenous genetic material. One of three horizontal gene transfer processes.
See also Conjugation, Transduction, Transfection