Acclimatisation
Adaptation of an organism to a new environment.
Action letter
An official FDA communication that informs an NDA or BLA sponsor of a decision by the agency. An approval letter allows commercial marketing of the product.
Active immunity
A type of acquired immunity whereby resistance to a disease is built up by either having the disease or receiving vaccination for it.
Adjuvant
Insoluble material that increases the formation and persistence of antibodies when injected with an antigen.
Aerobic
Requiring oxygen to live, grow and reproduce.
Agrobacterium tumefaciens
A common soil bacterium used as a vector to create transgenic plants.
Allele
Any of several alternative forms of a gene.
Allogenic
Of the same species, but with a different genotype. Also allogeneic.
Alzheimer's disease
A disease characterized by, among other things, progressive loss of memory. The development of Alzheimer's disease is thought to be associated, in part, with possessing certain alleles of the gene that encodes apolipoprotein E.
Aminoacids
Building blocks of proteins. There are 20 common amino acids: alanine, arginine, aspargine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine and valine. Two more amino acids have been discovered in microbes: selenocysteine and pyrrolysine.
Amplification
The process of increasing the number of copies of a particular gene or chromosomal sequence.
Anaerobic
Growing in the absence of oxygen.
Antibiotic
Chemical substance formed as a metabolic by-product in bacteria or fungi and used to treat bacterial infections. Antibiotics can be produced naturally, using microorganisms, or synthetically.
Antibody
Defensive protein produced by humans and higher animals in response to the presence of a specific antigen.
Anticodon
Triplet of nucleotide bases (codon) in transfer RNA that pairs with (is complementary to) a triplet in messenger RNA. For example, if the codon is UCG, the anticodon is AGC. See also Base; Base pair; Complementarity.
Antigen
A substance that, when introduced into the body, induces an immune response by a specific antibody.
Antigenic determinant
See Hapten.
Antiheamophilic factors
A family of whole-blood proteins that initiate blood clotting. Some of these proteins, such as factor VIII, can be used to treat haemophilia. See also Factor VIII; Kidney plasminogen activator.
Antisense
A piece of DNA producing a mirror image ("antisense") messenger RNA that is opposite in sequence to one directing protein synthesis. Antisense technology is used to selectively turn off production of certain proteins.
Antiserum
Blood serum containing specific antibodies against an antigen. Antisera are used to confer passive immunity to many diseases.
Apolipoprotein E (Apo E)
Certain alleles of the gene that encodes the protein apolipoprotein E have been associated with the development of heart disease and Alzheimer's disease.
Assay
Technique for measuring a biological response.
Attenuated
Weakened; with reference to vaccines, made from pathogenic organisms that have been treated so as to render them avirulent.
Autoimmune disease
A disease in which the body produces antibodies against its own tissues.
Autoimmunity
A condition in which the body mounts an immune response against one of its own organs or tissues.
Autosome
Any chromosome other than a sex chromosome.
Avirulent
Unable to cause disease.

Bacillus subtilis
A bacterium commonly used as a host in recombinant DNA experiments. Important because of its ability to secrete proteins.
Bacillus thuringiensis (Bt)
Naturally occurring soil bacterium that generates a protein toxic to a variety of lepidoptera, such as corn borers, but is harmless to people and animals.
Bacteriophage
Virus that uses bacteria to reproduce and in the process kills them. Also called phage.
Bacterium
Any of a large group of microscopic organisms with a very simple cell structure. Some manufacture their own food, some live as parasites on other organisms, and some live on decaying matter.
Base
A key component of DNA and RNA molecules. Four different bases are found in DNA: adenine (A), cytosine (C), guanine (G) and thymine (T). In RNA, uracil (U) substitutes for thymine. Also known as nitrogenous bases. A base, a phosphate molecule and a sugar joined together constitute a nucleotide.
Base pair
Two nucleotide bases on different strands of the nucleic acid molecule that bond together. The bases can pair in only one way: adenine with thymine (DNA) or uracil (RNA), and guanine with cytosine.
Bioassay
Determination of the effectiveness of a compound by measuring its effect on animals, tissues or organisms in comparison with a standard preparation.
Bioaugmentation
Increasing the activity of bacteria that break down pollutants by adding more of their kind. A technique used in bioremediation.
Biocatalyst
In bioprocessing, and in general, an enzyme that activates or speeds up a biochemical reaction.
Biochemical
The product of a chemical reaction in a living organism.
Biochip
An electronic device that uses organic molecules to form a semiconductor.
Bioconversion
Chemical restructuring of raw materials by using a biocatalyst.
Biodegradable
Capable of being reduced to water and carbon dioxide by the action of microorganisms.
Bioenrichment
A bioremediation strategy that involves adding nutrients or oxygen, thereby bolstering the activity of microbes as they break down pollutants.
Bioinformatics
The science of informatics as applied to biological research. Informatics is the management and analysis of data using advanced computing techniques. Bioinformatics is particularly important as an adjunct to genomics research, because of the large amount of complex data this research generates.
Biolistic device
A device that shoots microscopic DNA-coated particles into target cells.
Biological oxygen demand (BOD)
The amount of dissolved oxygen available for biological use within water.
Biologic (Biologic response modifier)
A substance that alters the growth or functioning of a cell. Includes hormones and compounds that affect the nervous and immune systems.
Biomass
The totality of biological matter in a given area. As commonly used in biotechnology, refers to the use of cellulose, a renewable resource, for the production of chemicals that can be used to generate energy or as alternative feedstocks for the chemical industry to reduce dependence on non-renewable fossil fuels.
Biomaterials
Biological molecules, such as proteins and complex sugars, used to make medical devices, including structural elements used in reconstructive surgery. Also includes biodegradable plastics and packaging.
Bioprocess
A process in which living cells, or components thereof, are used to produce a desired product.
Bioreactor
Vessel used for bioprocessing.
Bioremediation
The use of microorganisms to remedy environmental problems, rendering hazardous wastes non hazardous.
Biosynthesis
Production of a chemical by a living organism.
Biotechnology
The use of biological processes to solve problems or make useful products.
Biotransformation
The use of enzymes in chemical synthesis to produce chemical compounds of a desired stereochemistry.
Blastocyst (Blastula)
The 4- to 5-day-old ball of undifferentiated cells from which a prospective embryo develops. In mammals it consists of two distinct parts: the inner cell mass and the trophoblast.
B lymphocytes (B-cells)
A class of lymphocytes, released from the bone marrow, that produce antibodies.
Bovine somatotropin (BST)
A hormone secreted by the bovine pituitary gland. It is used to increase milk production by improving the feed efficiency in dairy cattle milk. Also called bovine growth hormone.
BRCA1 and BRCA2 (BReast CAncer genes 1 and 2)
Two genes that normally help to restrain cell growth, but which can contain certain genetic mutations associated with the development of breast and ovarian cancer. Note, however, that inherited BRCA1 and BRCA2 mutations are thought to account for less than 10 percent of all breast and ovarian cancers. Recent evidence suggests that somatic cell genetic mutations (i.e., non inherited genetic mutations) in these two genes may also play a role in the development of cancer.
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C
Callus
A cluster of undifferentiated plant cells that can, in some species, be induced to form the whole plant.
Carbohydrate
A type of biological molecule composed of simple sugars such as glucose. Common examples include starch and cellulose.
Carcinogen
Cancer-causing agent.
Catalyst
An agent (such as an enzyme or a metallic complex) that facilitates a reaction but is not itself changed during the reaction.
Cell
The smallest structural unit of a living organism that can grow and reproduce independently.
Cell culture
Growth of cells under laboratory conditions.
Cell fusion
See Fusion.
Cell line
Cells that grow and replicate continuously outside the living organism.
Cell-mediated immunity
Acquired immunity in which T lymphocytes play a predominant role. Development of the thymus in early life is critical to the proper development and functioning of cell-mediated immunity.
Chemical genomics
Using structural and functional genomic information about biological molecules, especially proteins, to identify useful small molecules and alter their structure to improve their efficacy.
Chimera
The individual (animal or lower organism) produced by grafting an embryonic part of one individual onto an embryo of either the same or a different species.
Chromosomes
Threadlike components in the cell that contain DNA and proteins. Genes are carried on the chromosomes.
Clinical studies
Human studies that are designed to measure the efficacy of a new drug or biologic. Clinical studies routinely involve the use of a placebo group that is given an inactive substance that looks like the test product.
Clone
A term that is applied to genes, cells or entire organisms that are derived from — and are genetically identical to — a single common ancestor gene, cell or organism, respectively. Cloning of genes and cells to create many copies in the laboratory is a common procedure essential for biomedical research. Note that several processes commonly described as cell "cloning" give rise to cells that are almost but not completely genetically identical to the ancestor cell. Cloning of organisms from embryonic cells occurs naturally in nature (e.g., identical twins). Researchers have achieved laboratory cloning using genetic material from adult animals of several species including mice, pigs and sheep.
Codon
A sequence of three nucleotide bases that specifies an amino acid or represents a signal to stop or start a function.
Co-enzyme
An organic compound that is necessary for the functioning of an enzyme. Co-enzymes are smaller than the enzymes themselves and sometimes separable from them.
Co-factor
A non protein substance required for certain enzymes to function. Co-factors can be co-enzymes or metallic icons.
Colony-stimulating factors (CSFs)
A group of lymphokines that induce the maturation and proliferation of white blood cells from the primitive cell types present in bone marrow.
Combinatorial chemistry
A product discovery technique that uses robotics and parallel synthesis to generate and screen quickly as many as several million molecules with similar structure in order to find chemical molecules with desired properties.
Co-metabolism
A microbe oxidizing not only its main energy source but also another organic compound.
Complementarity
The relationship of the nucleotide bases on two different strands of DNA or RNA. When the bases are paired properly (adenine with thymine [DNA] or uracil [RNA]; guanine with cytosine), the strands are complementary.
Complementary DNA (cDNA)
DNA synthesized from a messenger RNA rather than from a DNA template. This type of DNA is used for cloning or as a DNA probe for locating specific genes in DNA hybridization studies.
Computational biology
A sub discipline within bioinformatics concerned with computation-based research devoted to understanding basic biological processes.
Contraindications
Conditions under which a drug should not be prescribed
Conjugation
Sexual reproduction of bacterial cells in which there is a one-way exchange of genetic material between the cells in contact.
CRO
Contract Research Organisation
Crossing over
Exchange of genes between two paired chromosomes.
Cross-licensing
Legal, contractual procedure in which two or more firms with competing, similar technologies and possible conflicting patent claims strike a deal to reduce the need for legal actions to clarify who is to profit from applications of the technology.
Culture
As a noun, cultivation of living organisms in prepared medium; as a verb, to grow in prepared medium.
Culture medium
Any nutrient system for the artificial cultivation of bacteria or other cells; usually a complex mixture of organic and inorganic materials.
Cyto-
Referring to cell or cell plasm.
Cytokines
Soluble substances secreted by cells, which have a variety of effects on other cells, e.g. Interleukin 1 (Il-1).
Cytogenetics
Study of the cell and its heredity-related components, especially chromosomes.
Cytoplasm
Cellular material that is within the cell membrane and surrounds the nucleus.
Cytotoxic
Chemicals that are directly toxic to cells.
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D
Deoxyribonucleic acid (DNA)
The molecule that carries the genetic information for most living systems. The DNA molecule consists of four bases (adenine, cytosine, guanine and thymine) and a sugar-phosphate backbone, arranged in two connected strands to form a double helix. See also Complementary DNA; Double helix; Recombinant DNA.
Differentiation
The process of biochemical and structural changes by which cells become specialized in form and function.
Diploid
A cell with two complete sets of chromosomes. Compare Haploid.
DNA
See Deoxyribonucleic acid.
DNA chip
A small piece of glass or silicon that has small pieces of DNA arrayed on its surface.
DNA fingerprinting
The use of restriction enzymes to measure the genetic variation of individuals. This technology is often used as a forensic tool to detect differences or similarities in blood and tissue samples at crime scenes.
DNA hybridisation
The formation of a double-stranded nucleic acid molecule from two separate strands. The term also applies to a molecular technique that uses one nucleic acid strand to locate another.
DNA library
A collection of cloned DNA fragments that collectively represent the genome of an organism.
DNA polymerase
An enzyme that replicates DNA. DNA polymerase is the basis of PCR — the polymerase chain reaction.
DNA probe
A small piece of nucleic acid that has been labelled with a radioactive isotope, dye or enzyme and is used to locate a particular nucleotide sequence or gene on a DNA molecule.
DNA repair enzymes
Proteins that recognize and repair certain abnormalities in DNA.
DNA sequence
The order of nucleotide bases in the DNA molecule.
DNA vaccines
Pieces of foreign DNA that are injected into an organism to trigger an immune response.
Double helix
A term often used to describe the configuration of the DNA molecule. The helix consists of two spiralling strands of nucleotides (a sugar, phosphate and base) joined crosswise by specific paring of the bases. See also Deoxyribonucleic acid; Base; Base pair.
Diagnostic
A product used for the diagnosis of disease or medical condition. Both monoclonal antibodies and DNA probes are useful diagnostic products. Also includes environmental products.
Double Blind Trial
A type of clinical investigation where neither the investigator nor the patient knows whether they are using an active or non-active ingredient in their treatment.
Drug delivery
The process by which a formulated drug is administered to the patient. Traditional routes have been oral or intravenous perfusion. New methods deliver through the skin with a transdermal patch or across the nasal membrane with an aerosol spray.
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E
Electrophoresis
A technique for separating different types of molecules, usually proteins, based on their patterns of movement in an electrical field.
Electroporation
The creation of reversible small holes in a cell wall or membrane through which foreign DNA can pass. This DNA can then integrate into the cell's genome.
Enzyme-linked immunosorbent assay (ELISA)
A technique for detecting specific proteins by using antibodies linked to enzymes.
Embryonic stem cells
Cells that can give rise to any type of differentiated cell. They can be derived from two sources: the inner cell mass from a blastocyst or the primordial germ cells (eggs and sperm) of an older embryo.
EMEA
European Medicines Evaluation Agency
Endostatin
An endogenous protein that blocks the proliferation of blood vessels.
Enzyme
A protein catalyst that facilitates or enhances specific chemical or metabolic reactions necessary for cell growth and reproduction.
Erythropoietin (EPO)
A protein that boosts production of red blood cells. It is clinically useful in treating certain types of anaemia.
Escherichia coli (E. coli)
A bacterium that inhabits the intestinal tract of most vertebrates. Much of the work using recombinant DNA techniques has been carried out with this organism because it has been genetically well characterized.
Eukaryote
A cell or organism containing a true nucleus, with a well-defined membrane surrounding the nucleus. All organisms except bacteria, viruses and cyanobacteria are eukaryotic. Compare Prokaryote.
Exon
In eukaryotic cells, that part of the gene that is transcribed into messenger RNA and encodes a protein. See also Intron; Splicing.
Expression
In genetics, manifestation of a characteristic that is specified by a gene. With hereditary disease, for example, a person can carry the gene for the disease but not actually have the disease. In this case, the gene is present but not expressed. In industrial biotechnology, the term is often used to mean the production of a protein by a gene that has been inserted into a new host organism.
Extremophiles
Microorganisms that live at extreme levels of pH, temperature, pressure orand salinity.
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F
Factor VIII
A large, complex protein that aids in blood clotting and is used to treat haemophilia. See also Antihemophilic factors.
FDA
Food and Drugs Administration
Feedstock
The raw material used for chemical or biological processes.
Fermentation
The process of growing microorganisms for the production of various chemical or pharmaceutical compounds. Microbes are normally incubated under specific conditions in the presence of nutrients in large tanks called fermentors.
Functional foods
Foods containing compounds with beneficial health effects beyond those provided by the basic nutrients, minerals and vitamins. Also called nutraceuticals.
Functional genomics
A field of research that aims to understand what each gene does, how it is regulated and how it interacts with other genes.
Fusion
Joining of the membrane of two cells, thus creating a daughter cell that contains some of the same properties from each parent cells. Used in making hybridomas.
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G
Gel electrophoresis
A process for separating molecules by forcing them to migrate through a gel under the influence of an electric field.
Gene
A segment of chromosome. Some genes direct the syntheses of proteins, while others have regulatory functions. See also Operator gene; Structural gene; Suppressor gene.
Gene amplification
The increase, within a cell, of the number of copies of a given gene.
Gene knockout
The replacement of a normal gene with a mutated form of the gene by using homologous recombination. Used to study gene function.
Gene machine
A computerised device for synthesizing genes by combing nucleotides (bases) in the proper order.
Gene mapping
Determination of the relative locations of genes on a chromosome.
Gene sequencing
Determination of the sequence of nucleotide bases in a strand of DNA. See also Sequencing.
Gene therapy
The replacement of a defective gene in an organism suffering from a genetic disease. Recombinant DNA techniques are used to isolate the functioning gene and insert it into cells. More than 300 single-gene genetic disorders have been identified in humans. A significant percentage of these may be amenable to gene therapy.
Genetic code
The code by which genetic information in DNA is translated into biological function. A set of three nucleotides (codons), the building blocks of DNA, signifies one amino acid, the building blocks of proteins.
Genetic modification
A number of techniques, such as selective breeding, mutagenesis, transposon insertions and recombinant DNA technology, that are used to alter the genetic material of cells in order to make them capable of producing new substances, performing new functions or blocking the production of substances.
Genetic predisposition
Susceptibility to disease that is related to a genetic predisposition mutation, which may or may not result in actual development of the disease.
Genetic screening
The use of a specific biological test to screen for inherited diseases or medical conditions. Testing can be conducted prenatally to check for metabolic defects and congenital disorders in the developing foetus as well as postnatally to screen for carriers of heritable diseases.
Genetic testing
The analysis of an individual's genetic material. Genetic testing can be used to gather information on an individual's genetic predisposition to a particular health condition, or to confirm a diagnosis of genetic disease.
Genome
The total hereditary material of a cell, comprising the entire chromosomal set found in each nucleus of a given species.
Genomics
The study of genes and their function. Recent advances in genomics are bringing about a revolution in our understanding of the molecular mechanisms of disease, including the complex interplay of genetic and environmental factors. Genomics is also stimulating the discovery of breakthrough health-care products by revealing thousands of new biological targets for the development of drugs and by giving scientists innovative ways to design new drugs, vaccines and DNA diagnostics. Genomic-based therapeutics may include "traditional" small chemical drugs, protein drugs and gene therapy.
Genotype
Genetic makeup of an individual or group. Compare Phenotype.
Germ cell
Reproductive cell (sperm or egg). Also called gamete or sex cell.
Germplasm
The total genetic variability, represented by germ cells or seeds, available to a particular population of organisms.
Glycoprotein
A protein conjugated with a carbohydrate group.
GCP
Good clinical practice
GLP
Good laboratory practice.
GMP
Good manufacturing practice.
Granulocyte
One of three types of white blood cells. Granulocytes digest bacteria and other parasites.
Granulocyte-macrophage colony stimulating factor (GMCSF)
A natural hormone that stimulates white blood cell production, particularly that of granulocytes and monocytes (the precursors of macrophages).
Growth factors
Naturally occurring proteins that stimulate the growth and reproduction of specific cell types. Growth factors are essential to regenerative medicine and tissue engineering.
Growth hormone
A protein produced by the pituitary gland that is involved in cell growth. Human growth hormone is used clinically to treat dwarfism. Various animal growth hormones can be used to improve milk production as well as produce a leaner variety of meat. Also called somatotropin.
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H
Haploid
A cell with half the usual number of chromosomes, or only one chromosome set. Sex cells are haploid. Compare Diploid.
Hapten
The portion of an antigen that determines its immunological specificity. When coupled to a large protein, a hapten stimulates the formation of antibodies to the two-molecule complex. Also called antigenic determinant.
Haemagglutination
Clumping (agglutination) of red blood cells.
Heredity
Transfer of genetic information from parent cells to progeny.
Histocompatibility
Immunologic similarity of tissues such that grafting can be done without tissue rejection.
Histocompatibility antigen
An antigen that causes the rejection of grafted material from an animal different in genotype from the host animal.
Homeobox
Family of genes that regulates activities of other genes (turns genes on and off).
Homologous
Corresponding or alike in structure, position or origin.
Hormone
A chemical or protein that acts as a messenger or stimulatory signal, relaying instructions to stop or start certain physiological activities. Hormones are synthesized in one type of cell and then released to direct the function of other cell types.
Host
A cell or organism used for growth of a virus, plasmid or other form of foreign DNA, or for the production of cloned substances.
Host-vector system
Combination of DNA-receiving cells (host) and DNA-transporting substance (vector) used for introducing foreign DNA into a cell.
Human Genome Project
An international research effort aimed at discovering the full sequence of bases in the human genome. Led in the United States by the National Institutes of Health and the Department of Energy. The UK Human Genome Mapping Project Resource Centre (HGMP-RC) provides access to leading-edge tools for research in the fields of genomics, genetics and functional genomics. The Research Division and the Bioinformatics Division are located on the Hinxton Genome Campus along with the Wellcome Trust Sanger Institute and the European Bioinformatics Institute. MRC geneservice of the HGMP-RC is located on the site of the Babraham Institute, Babraham.
Human immunodeficiency virus (HIV)
The virus that causes acquired immune deficiency syndrome (AIDS).
Hybridization
Production of offspring, or hybrids, from genetically dissimilar parents. The process can be used to produce hybrid plants (by crossbreeding two different varieties) or hybridomas (hybrid cells formed by fusing two unlike cells, used in producing monoclonal antibodies). See DNA hybridization.
Hybridoma
The cell produced by fusing two cells of different origin. In monoclonal antibody technology, hybridomas are formed by fusing an immortal cell (one that divides continuously) and an antibody-producing cell. See also Monoclonal antibody; Myeloma.
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I
Immune response
The response of the immune system to challenge by a foreign antigen.
Immune serum
Blood serum containing antibodies.
Immune system
The combination of cells, biological substances (such as antibodies) and cellular activities that work together to provide resistance to disease.
Immunity
Non susceptibility to a disease or to the toxic effects of antigenic material. See also Active immunity; Cell-mediated immunity; Natural active immunity; Natural passive immunity; Passive immunity.
Immunoassay
Technique for identifying substances based on the use of antibodies.
Immunodiagnostics
The use of specific antibodies to measure a substance. This tool is useful in diagnosing infectious diseases and the presence of foreign substances in a variety of human and animal fluids (blood, urine, etc.). It is currently being investigated as a way of locating tumour cells in the body.
Immunofluorescence
Technique for identifying antigenic material that uses an antibody labelled with fluorescent material. Specific binding of the antibody and antigen can be seen under a microscope by applying ultraviolet light rays and noting the visible light that is produced.
Immunogen
Any substance that can elicit an immune response.
Immunoglobulin
General name for proteins that function as antibodies. These proteins differ somewhat in structure and are grouped into five categories on the basis of these differences; immunoglobulin G (IgG), IgM, IgA, IgE and IgD.
Immunology
Study of all phenomena related to the body's response to antigenic challenge (i.e., immunity, sensitivity and allergy).
Immunomodulators
A diverse class of proteins that boost the immune system. Many are cell growth factors that accelerate the production of specific cells that are important in mounting an immune response in the body. These proteins are being investigated for use in possible cures for cancer.
Immunotoxins
Specific monoclonal antibodies that have a protein toxin molecule attached. The monoclonal antibody is targeted against a tumour cell, and the toxin is designed to kill that cell when the antibody binds to it.
Inducer
A molecule or substance that increases the rate of enzyme synthesis, usually by blocking the action of the corresponding repressor.
In situ
In its original or natural place or position.
Interferon
A class of lymphokine proteins important in the immune response. There are three major types of interferon: alpha (leukocyte), beta (fibroblast) and gamma (immune). Interferons inhibit viral infections and may have anticancer properties.
Interleukin
A type of lymphokine that regulates the growth and development of white blood cells. Twelve interleukins (IL-1 through IL-12) have been identified to date.
Intron
In eukaryotic cells, a sequence of DNA that is contained in the gene but does not encode for protein. The presence of introns "splits" the coding region of the gene into segments called exons. See also Exon; Splicing.
Investigational New Drug Application (IND)
An application to begin studies of a new drug or biologic on humans. The IND gives the plan for the study and contains formulation, manufacturing and animal test result information.
In vitro
Literally, "in glass." Performed in a test tube or other laboratory apparatus.
In vivo
In the living organism.
Islet cells
Pancreatic cells that are the source of insulin and two other hormones involved in regulating glucose metabolism and absorption.
Isoenzyme
One of the several forms that a given enzyme can take. The forms may differ in certain physical properties, but function similarly as biocatalysts.
Isogenic
Of the same genotype.

K
Kidney plasminogen activator
A precursor to the enzyme urokinase that has blood-clotting properties.
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L
Leukocyte
A colourless cell in the blood, lymph and tissues that is an important component of the body's immune system. Also called white blood cells.
Library
A set of cloned DNA fragments that taken collectively contain the entire genome of an organism. Also called a DNA library.
Ligase
An enzyme used to join DNA or RNA segments together. They are called DNA ligase or RNA ligase, respectively.
Linkage
The tendency for certain genes to be inherited together due to their physical proximity on the chromosome.
Linker
A fragment of DNA with a restriction site that can be used to join DNA strands.
Lipoproteins
A class of serum proteins that transport lipids and cholesterol in the blood stream. Abnormalities in lipoprotein metabolism have been implicated in certain heart diseases.
Lymphocyte
A type of leukocyte found in lymphatic tissue in the blood, lymph nodes and organs. Lymphocytes are continuously made in the bone marrow and mature into antibody-forming cells. See also B lymphocytes; T lymphocytes.
Lymphokine
A class of soluble proteins produced by white blood cells that play a role, as yet not fully understood, in the immune response. See also Interferon; Interleukin.
Lymphoma
Form of cancer that affects the lymph tissue.
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M
Macrophage
A type of white blood cell produced in blood vessels and loose connective tissues that can ingest dead tissues and cells and is involved in producing interleukin-1. When exposed to the lymphokine macrophage-activating factor, macrophages also kill tumour cells. See also Phagocyte.
Macrophage colony stimulating factor (M-CSF)
A natural hormone that stimulates the production of white blood cells, particularly monocytes (the precursors of macrophages).
MCA
Medicines Control Agency
Medium
A substance containing nutrients needed for cell growth.
Meiosis
Process of cell reproduction whereby the daughter cells have half the chromosome number of the parent cells. Sex cells are formed by meiosis. Compare Mitosis.
Messenger RNA (mRNA)
Nucleic acid that carries instructions to a ribosome for the synthesis of a particular protein.
Metabolism
All biochemical activities carried out by an organism to maintain life.
Microbial herbicides and pesticides
Microorganisms that are toxic to specific plants or insects. Because of their narrow host range and limited toxicity, these microorganisms may be preferable to their chemical counterparts for certain pest control applications.
Microbiology
Study of living organisms that can be seen only under a microscope.
Microinjection
The injection of DNA using a very fine needle into a cell.
Microorganism
Any organism that can be seen only with the aid of a microscope. Also called microbe.
Mitosis
Process of cell reproduction whereby the daughter cells are identical in chromosome number to the parent cells. Compare Meiosis.
Molecular genetics
Study of how genes function to control cellular activities.
Monoclonal antibody (MAb)
Highly specific, purified antibody that is derived from only one clone of cells and recognizes only one antigen. See also Hybridoma; Myeloma.
Monocytes
One of three types of white blood cells. Monocytes are precursors to macrophages.
Multigenic
Of hereditary characteristics, one that is specified by several genes.
Mutagen
A substance that induces mutations.
Mutant
A cell that manifests new characteristics due to a change in its DNA.
Mutation
A permanent transmissible change in the genetic material of a cell.
Myeloma
A type of tumour cell that is used in monoclonal antibody technology to form hybridomas.
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N
Natural active immunity
Immunity that is established after the occurrence of a disease.
Natural killer cell (NK)
A type of leukocyte that attacks cancerous or virus-infected cells without previous exposure to the antigen. NK cell activity is stimulated by interferon.
Natural passive immunity
Immunity conferred by the mother on the foetus or newborn.
NDA
New Drug Application
Nitrogen fixation
A biological process (usually associated with plants) whereby certain bacteria convert nitrogen in the air to ammonia, thus forming a nutrient essential for growth.
Nitrogenous base
See Base.
Non coding DNA
DNA that does not encode any product (RNA or protein). The majority of the DNA in plants and animals is none coding.
Nuclease
An enzyme that, by cleaving chemical bonds, breaks down nucleic acids into their constituent nucleotides.
Nucleic acids
Large molecules, generally found in the cell's nucleus and/or cytoplasm, that are made up of nucleotides. The two most common nucleic acids are DNA and RNA.
Nucleotides
The building blocks of nucleic acids. Each nucleotide is composed of sugar, phosphate and one of four nitrogen bases. The sugar in DNA is deoxyribose and RNA's sugar is ribose. The sequence of the bases within the nucleic acid determines the sequence of amino acids in a protein. See also Base.
Nucleus
The structure within eukaryotic cells that contains chromosomal DNA.

O
Oligonucleotide
A polymer consisting of a small number (about two to 10) of nucleotides.
Oncogene
Mutated or overexpressed variant of a normal gene. Can cause uncontrolled growth resulting in tumor formation.
Oncogenic
Cancer causing.
Oncology
Study of tumours.
Operator gene
A region of the chromosome, adjacent to the operon, where a repressor protein binds to prevent transcription of the operon.
Operon
Sequence of genes responsible for synthesizing the enzymes needed for biosynthesis of a molecule. An operon is controlled by an operator gene and a repressor gene.
Organic compound
A compound containing carbon.
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P
Passive immunity
Immunity acquired from receiving preformed antibodies.
Pathogen
Disease-causing organism.
Peptide
Two or more amino acids joined by a linkage called a peptide bond.
Phagocyte
A type of white blood cell that can ingest invading microorganisms and other foreign material. See also Macrophage.
Pharmacodynamics
The study of the biochemical and physiological effects of drugs and the mechanisms of the actions, including the correlation of actions and effects of drugs with their chemical structure
Pharmacokinetics
The action of drugs in the body over a period of time, including the processes of absorption, distribution, localisation in tissues, metabolism and excretion.
Pharmacovigilance
Continued monitoring of a product after it has been marketed.
Phenotype
Observable characteristics resulting from interaction between an organism's genetic makeup and the environment. Compare Genotype.
Photosynthesis
Conversion by plants of light energy into chemical energy, which is then used to support the plants' biological processes.
Phytoremediation
The use of plants to clean up pollution.
Placebo
An inactive substance used as a comparison with an active drug.
Plasma
The fluid (non cellular) fraction of blood.
Plasmapheresis
A technique used to separate useful factors from blood.
Plasmid
A small circular form of DNA that carries certain genes and is capable of replicating independently in a host cell.
Pluripotent cells
Having the capacity to become any kind of cell or tissue in the body. Embryonic stem cells and cells of the inner cell mass are pluripotent. Adult stem cells are multipotent. The mammalian embryo (blastocyst trophoblast plus inner cell mass) is totipotent because it can become an entire organism. Fully differentiated cells from many plants are totipotent.
Polyclonal
Derived from different types of cells.
Polymer
A long molecule of repeated subunits.
Polymerase
General term for enzymes that carry out the synthesis of nucleic acids.
Polymerase chain reaction (PCR)
A technique to amplify a target DNA sequence of nucleotides by several hundred thousand fold.
Polypeptide
Long chain of amino acids joined by peptide bonds.
Preclinical studies
Studies that test a drug on animals and in other nonhuman test systems. Safety information from such studies is used to support an investigational new drug application (IND).
Prokaryote
An organism (e.g., bacterium, virus, cyrobacterium) whose DNA is not enclosed within a nuclear membrane. Compare Eukaryote.
Promoter
A DNA sequence that is located in front of a gene and controls gene expression. Promoters are required for binding of RNA polymerase to initiate transcription.
Prophage
Phage nucleic acid that is incorporated into the host's chromosome but does not cause cell lysis.
Protein
A molecule composed of amino acids. There are many types of proteins, all carrying out a number of different functions essential for cell growth.
Protein A
A protein produced by the bacterium Staphylococcus aureus that specifically binds antibodies. It is useful in the purification of monoclonal antibodies.
Proteomics
Each cell produces thousands of proteins, each with a specific function. This collection of proteins in a cell is known as the proteome, and, unlike the genome, which is constant irrespective of cell type, the proteome varies from one cell type to the next. The science of proteomics attempts to identify the protein profile of each cell type, assess protein differences between healthy and diseased cells, and uncover not only a protein's specific function but also how it interacts with other proteins.
Protoplast
The cellular material that remains after the cell wall has been removed from plant and fungal cells.
Pure culture
In vitro growth of only one type of microorganism

R
R&D
Research and Development
Radioimmunoassay (RIA)
A test combining radioisotopes and immunology to detect trace substances. Such tests are useful for studying antibody interactions with cell receptors, and can be developed into clinical diagnostics.
Rational drug design
Using the known three-dimensional structure of a molecule, usually a protein, to design a drug molecule that will bind to it. Usually viewed as an alternative to drug discovery through screening many molecules for biological activity.
Reagent
Substance used in a chemical reaction.
Recombinant DNA (rDNA)
The DNA formed by combining segments of DNA from two different sources.
Regeneration
Laboratory technique for forming a new plant from a clump of plant cells.
Regulatory gene
A gene that acts to control the protein-synthesizing activity of other genes.
Replication
Reproduction or duplication, as of an exact copy of a strand of DNA.
Replicon
A segment of DNA (e.g., chromosome or plasmid) that can replicate independently.
Repressor
A protein that binds to an operator adjacent to a structural gene, inhibiting transcription of that gene.
Restriction enzyme
An enzyme that breaks DNA in highly specific locations, creating gaps into which new genes can be inserted.
Restriction fragment length polymorphism (RFLP)
The variation in the length of DNA fragments produced by a restriction endonuclease that cuts at a polymorphic locus. This is a key tool in DNA fingerprinting and is based on the presence of different alleles in an individual. RFLP mapping is also used in plant breeding to see if a key trait such as disease resistance is inherited.
Reticuloendothelial system
The system of macrophages, which serves as an important defence system against disease.
Retrovirus
A virus that contains the enzyme reverse transcriptase. This enzyme converts the viral RNA into DNA, which can combine with the DNA of the host cell and produce more viral particles.
Rheology
Study of the flow of matter such as fermentation liquids.
Rhizobium
A class of microorganisms that converts atmospheric nitrogen into a form that plants can utilize for growth. Species of this microorganism grow symbiotically on the roots of certain legumes, such as peas, beans and alfalfa.
Ribonucleic acid (RNA)
A molecule similar to DNA that delivers DNA's genetic message to the cytoplasm of a cell where proteins are made.
Ribosome
A cellular component, containing protein and RNA, that is involved in protein synthesis.
RNA interference
A natural process used by organisms to block protein production.
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S
Scale-up
Transition from small-scale production to production of large industrial quantities.
Selective medium
Nutrient material constituted such that it will support the growth of specific organisms while inhibiting the growth of others.
Sepsis
The presence in the blood or other tissues of pathogenic microorganisms or their toxins; the condition associated with such presence.
Sequencing
Decoding a strand of DNA or gene into the specific order of its nucleotides: adenine, cytosine, guanine and thymine. This analysis can be done manually or with automated equipment. Sequencing a gene can require analyzing an average of 40,000 nucleotides.
Serology
Study of blood serum and reactions between the antibodies and antigens therein.
Single-cell protein
Cells or protein extracts from microorganisms, grown in large quantities for use as protein supplements.
Somatic cells
Cells other than sex or germ cells.
Somatic cell gene therapy
Somatic cell gene therapy involves the insertion of genes into cells for therapeutic purposes; for example, to induce the treated cells to produce a protein that the body is missing. It does not affect genetic makeup of a patient's offspring and generally does not change all, or even most, cells in the recipient. Somatic cell gene therapy is only one way of applying the science of genomics to improve health care.
Splicing
The removal of introns and joining of exons to form a continuous coding sequence in RNA.
Stop codon
One of three codons in messenger RNA that signal the end of the amino acid chain in protein synthesis.
Structural gene
A gene that codes for a protein, such as an enzyme.
Substrate
Material acted on by an enzyme.
Suicide gene
A gene that codes for an antibiotic that can kill the host bacterial cell. It is genetically modified into the bacterium along with a molecular switch that is controlled by a nutrient in the environment. When the nutrient disappears, the suicide gene is switched on and the bacterium dies.
Suppressor gene
A gene that can reverse the effect of a mutation in other genes.
Systems biology
A hypothesis-driven field of research that creates predictive mathematical models of complex biological processes or organ systems.
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T
Technology transfer
The process of transferring discoveries made by basic research institutions, such as universities and government laboratories, to the commercial sector for development into useful products and services.
Template
A molecule that serves as the pattern for synthesizing another molecule.
Terminator
Sequence of DNA bases that tells the RNA polymerase to stop synthesizing RNA.
Tertiary structure
The total three-dimensional shape of a protein that is essential to protein function.
Therapeutics
Compounds that are used to treat specific diseases or medical conditions.
Thymus
A lymphoid organ in the lower neck, the proper functioning of which in early life is necessary for development of the immune system.
Tissue culture
In vitro growth in nutrient medium of cells isolated from tissue.
Tissue plasminogen activator (tPA)
A protein produced in small amounts in the body that aids in dissolving blood clots.
T lymphocytes (T-cells)
White blood cells that are produced in the bone marrow but mature in the thymus. They are important in the body's defence against certain bacteria and fungi, help B lymphocytes make antibodies and help in the recognition and rejection of foreign tissues. T lymphocytes may also be important in the body's defence against cancers.
Toxin
A poisonous substance produced by certain microorganisms or plants.
Transcription
Synthesis of messenger (or any other) RNA on a DNA template.
Transdifferentiation
The process whereby a specialized cell de-differentiates and re-differentiates into a different cell type; or the process whereby an adult stem cell from a specific tissue type becomes a cell type from a very different tissue (for example a nerve stem cell differentiates into a kidney cell).
Transduction
Transfer of genetic material from one cell to another by means of a virus or phage vector.
Transfection
Infection of a cell with nucleic acid from a virus, resulting in replication of the complete virus.
Transfer RNA (tRNA)
RNA molecules that carry amino acids to sites on ribosomes where proteins are synthesized.
Transformation
Change in the genetic structure of an organism by the incorporation of foreign DNA.
Transgenic organism
An organism formed by the insertion of foreign genetic material into the germ line cells of organisms. Recombinant DNA techniques are commonly used to produce transgenic organisms.
Translation
Process by which the information on a messenger RNA molecule is used to direct the synthesis of a protein.
Transposon
A segment of DNA that can move around and be inserted at several sites in bacterial DNA or in a phage, thus alerting the host's DNA.
Tumor necrosis factors (TNF)
Rare proteins of the immune system that appear to destroy some types of tumour cells without affecting healthy cells.
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V
Vaccine
A preparation that contains an antigen, consisting of whole disease-causing organisms (killed or weakened) or parts of such organisms, that is used to confer immunity against the disease that the organisms cause. Vaccine preparations can be natural, synthetic or derived by recombinant DNA technology.
Vector
The agent (e.g., plasmid or virus) used to carry new DNA into a cell.
Virion
An elementary viral particle consisting of genetic material and a protein covering.
Virology
Study of viruses.
Virulence
The degree of the ability to infect or cause disease.
Virus
A submicroscopic organism that contains genetic information but cannot reproduce itself. To replicate, it must invade another cell and use parts of that cell's reproductive machinery.
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W
White blood cells
Leukocytes.
Wild type
The form of an organism that occurs most frequently in nature.
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X
X-ray crystallography
An essential technique for determining the three-dimensional structure of biological molecules. This information aids in the discovery of products that will interact with the biological molecule.
Xenobiotics
Synthetic chemicals believed to be resistant to environmental degradation. A branch of biotechnology called bioremediation is seeking to develop biological methods to degrade such compounds.
Xenotransplantation
The transplantation of living organs, cells or tissues from animals into humans.
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Y
Yeast
A general term for single-celled fungi that reproduce by budding. Some yeasts can ferment carbohydrates (starches and sugars) and thus are important in brewing and baking.

The life science terms are very useful for easy identification and rectification of various names, the glossary will help best for this purpose. It contains one of the collection of various terms from different sectors such as development biology, genetic, cell biology, molecular biology, molecular genetic and biochemistry definitions. Could you please produce some attachment links about any additional terns in glossary.