Agrobacterium tumefaciens is a common soil bacterium that causes crown gall disease by transferring some of its DNA to the plant host. Scientists alter Agrobacterium so that it no longer causes the disease but is still able to transfer DNA. They then use this altered Agrobacterium to ferry desirable genes into plants. Amino acid is the fundamental building blocks of a protein molecule. A protein is composed of a chain of hundreds or thousands of amino acids. Our bodies can synthesize most of the amino acids. However, eight amino acids (called "essential amino acids") must be obtained from food. Antibody is a protein produced in response to the presence of a specific antigen. Antigen is a foreign substance that elicits the production of antibodies. Anti-sense technology is the use of an RNA molecule to block gene expression by interfering with protein production. This technique is used commercially in tomatoes to slow ripening for better shipping and longer shelf life. Assay is a method for determining the presence or quantity of a component. B lymphocytes (B cells) is a type of cell that produces antibodies. Bacillus thuringiensis is a naturally occurring bacterium with pesticidal properties. Bacillus thuringiensis produces a protein (Bt toxin) that is toxic only to certain insect larvae that consume it. Bacteriophage is a virus that infects bacteria. Also called a phage. Bioassay is a method of determining the effect of a compound by quantifying its effect on living organisms or their component parts. Biocatalyst is an enzyme that activates or speeds up a chemical reaction. Biological control is the use of one organism to control the population size of another organism. Biological molecules is large, complex molecules, such as proteins, nucleic acids, lipids and carbohydrates, that are produced only by living organisms. Biological molecules are often referred to as macromolecules or biopolymers. Bioprocessing is a technique in which microorganisms, living cells, or their components are used to produce a desired end product. Bioreactor is a container used for bioprocessing. Bioremediation is the use of organisms, usually microorganisms, to break down pollutants in soil, air or groundwater. Biosensor technology is the use of cells or biological molecules in an electronic system to detect specific substances. Consists of a biological sensing agent coupled with a microelectronic circuit. Biosynthesis is a production of a chemical by a living organism. Biotechnology is a collection of technologies that use living cells and/or biological molecules to solve problems and make useful products. Callus is a cluster of undifferentiated plant cells that have the capacity to regenerate a whole plant in some species. Catalyst is a substance that speeds up a chemical reaction, but is not itself changed during the reaction. Cell is the smallest structural unit of living organisms that is able to grow and reproduce independently. Cell culture is a technique for growing cells under laboratory conditions. Cell fusion is the formation of a hybrid cell produced by fusing two different cells. Chromosome are components in a cell that contain genetic information. Each chromosome contains numerous genes. Chromosomes occur in pairs: one obtained from the mother; the other from the father. Chromosomes of different pairs are often visibly different from each other. Clone is a cell or collection of cells containing identical genetic material. Clones are produced from a single parent cell. 
