GLOSSARY

Amino acids: organic compounds linked together in a linear chain to form proteins. There are 20 amino acids commonly found in proteins.

Antibodies: proteins produced by an organism's immune system that recognize foreign proteins (or their surface sugars). Specific antibodies can be produced in large volumes and employed to detect, diagnose, or treat one or more diseases.

Base: one of the four chemical units (nucleotides) arranged along the DNA or RNA molecule.

Base pair: a pair of nucleotides on complementary strands of DNA or RNA. Each nucleotide base can pair with only one of the three other bases, thereby determining the sequence of a complementary strand.

Bio-: prefix meaning "biologically based", often attached to various verbs and nouns (e.g., bioprocessing, biofactory) in a biotechnology context.

Biomass: materials and waste from living things that can be used as a source of fuel, energy, commodity chemicals, animal feed, and specialty products (e.g., flavors, fragrances, pigments).

Biomaterials: materials with novel chemical, physical, mechanical, or "intelligent" properties, produced through processes that employ or mimic biological phenomena.

Biomimetic: mimicking a biological substance or process.

Biomolecular materials: complex biological macromolecules that can have unusual combinations of properties (e.g., strong and supple yet lightweight). These materials comprise a subset of biomaterials.

Bioreactor: a chamber where biological growth, product formation, and/or enzymatic reactions occur.

Bioremediation: the use of living organisms or their products to degrade wastes into less toxic or non-toxic products and to concentrate and immobilize toxic elements, such as heavy metals. Bioremediation may be employed either on site or in bioreactors, using either native organisms or newly introduced ones, including genetically engineered varieties. The choice of organisms and treatments is determined by the nature of the toxic material and the biological and physical characteristics of the affected system.

Biosynthesis: production of a chemical compound by a living organism.

Cell: the smallest structural and functional unit of living organisms, generally having a nucleus, cytoplasm, and a surrounding membrane.

Chromosomes: Rod-like structures composed of highly coiled DNA and proteins.

Cloning: the use of techniques of molecular biology to produce multiple copies of segments of DNA, usually genes.

Dehalogenate: to remove chlorine or bromine ions from common organic contaminants and thereby reduce either their toxicity or the difficulty of degrading them.

DNA: deoxyribonucleic acid. The basic unit of DNA is the nucleotide (containing one of four bases). A DNA strand can be made up of thousands of nucleotides joined by a backbone of phosphate sugars. Chromosomes typically are constructed of two strands of DNA twisted together in the shape of a double helix. Specific nucleotide sequences define genes, which encode instructions for cell function and products (including proteins). The human genome contains 100,000 genes, or 3 x 109 base pairs; the simplest bacterium contains about 2,000 genes, or 2 million base pairs.

DNA probe: a fragment of DNA used to recognize a specific complementary DNA sequence, or gene(s). Probes can be employed, for example, to bind to the genetic material of microbes for purposes of detection, identification, or, in some cases, inactivation.

DNA "fingerprint": the chemical/physical profile of an organism's nucleotide sequences, typically determined from

segments of DNA that are 100 to 1,000 base pairs long. DNA fingerprints illuminate the genetic differences between and among individuals and are used in fields ranging from agricultural research to law enforcement. The extent of the variation depends on the target region of DNA being compared. Some regions appear to be common to all forms of life, while others are highly variable.

DNA sequencing: a technique for determining the order of nucleotide bases in a segment of DNA. This technique was made possible by the Nobel Prize-winning development of molecular cloning techniques for replicating genetic material. Automated sequencing technology is available now, and researchers are beginning to sequence entire genomes of free-living organisms, such as bacteria, yeast (single-celled fungi), and humans.

Enzymes: protein catalysts, produced by living cells, that facilitate specific chemical or metabolic reactions.

Enzyme-linked immunosorbent assay (ELISA): a sensitive, inexpensive assay technique involving the use of antibodies coupled with indicators (e.g., enzymes linked to dyes) to detect the presence of specific substances, such as enzymes, viruses, or bacteria.

Gene: the basic unit of heredity; an ordered sequence of nucleotide bases in a segment of DNA.

Genetic code: the biochemical basis of heredity; the sets of nucleotide bases in a DNA sequence that specify each amino acid in the sequence of a protein.

Genome: the total hereditary composition of a cell or organism.

Metabolism: all biochemical activities carried out by an organism to maintain life.

Microorganisms: organisms so small (e.g., bacteria and yeast) that they can be seen only with a microscope.

Molecular biology: general term referring to study of the structure and function of proteins and nucleic acids; may be used as a synonym for genetic engineering or recombinant DNA techniques.

Monoclonal antibodies: antibodies made from single cells that recognize one chemical component on a foreign target molecule.

Nitrogen fixing: conversion of atmospheric nitrogen gas to a chemically combined form, ammonia, which is essential to plant growth. Some microorganisms can "fix" nitrogen.

Nucleotide: see "base".

Pathogen: a specific causative agent of disease.

pH: a measure of the acidity or basicity of a solution.

Photosynthesis: the reaction carried out by plants in which energy from sunlight is used to convert carbon dioxide from the atmosphere into sugars and oxygen.

Polymerase chain reaction (PCR): a powerful technique for producing millions of copies of a specific region of DNA, so it can be analyzed as readily as can a purified chemical substance. PCR has been instrumental in major breakthroughs in diagnostic kit development, forensic medicine, and detection of genes associated with inborn errors of metabolism. A Nobel Prize in medicine was awarded in 1993 for the development of PCR.

Protease: an enzyme that digests proteins.

Protein: a linear polymer that, in its biologically active state, functions as a catalyst in metabolism or as a structural element of cells and tissues.

Protein engineering (genetic engineering): the alteration of DNA to encode the synthesis of new proteins that perform new functions. DNA is made of only four nucleotides, in varying sequences, so it can be modified more easily than can proteins, which are difficult to alter using standard chemical means. Protein engineering was the basis for a Nobel prize in 1994.

Quantitative trait loci: a combination of genes that often controls economically significant genetic traits, such as disease resistance in animals and, in dairy cattle, milk quality and quantity.

Recombinant DNA: the hybrid DNA produced by joining pieces of DNA from different organisms together in vitro. This is accomplished by inserting a desired DNA sequence into a vector (usually a circular strand of DNA or a virus), which then is introduced into another organism, often a bacterium.

Recombinant DNA technology: a broad term referring to molecular cloning as well as techniques for making recombinant DNA or using it for specific purposes.

RNA: ribonucleic acid, which is similar to a single strand of DNA but with a small chemical difference in the structure of the nucleotides. There are three classes: messenger RNA is the template for decoding the instructions contained in DNA, while transfer RNA and ribosomal RNA (located in structures known as ribosomes inside cells) follow these instructions to make proteins.

Transgenic organism: an organism formed by the insertion of foreign genetic material into a germ cell.

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