tailieunhanh - A Dictionary of Genetics phần 2

Tham khảo tài liệu 'a dictionary of genetics phần 2', ngoại ngữ, ngữ pháp tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | J r J J ơ PALEARCTIC Biston betularia 51 biorhythm a recurring cycle in the physiology or functioning of an organism such as the daily cycle of sleeping and waking a cyclic pattern of physical emotional or mental activity said to occur in the life of a person. See circadian rhythm. biosphere the surface of the earth where life resides. biosynthesis the production of a chemical compound by a living organism. biota a collective term to include all the organisms living in a given region. biotechnology the collection of industrial processes that involve the use of biological systems. For some industries these processes involve the use of genetically engineered microorganisms. biotic potential See reproductive potential. biotin one of the water-soluble B vitamins. It functions as a cofactor in enzymes that catalyze carboxylation reactions. Biotin is often used as a chemical tag on nucleic acid probes because biotin-scavenging proteins like streptavidin . bind it with high affinity. Biotin-binding proteins coupled with fluorescent dyes allow their detection on cytological preparations. See biotinylated DNA. o zc HN XNH 1 I HC-----CH 1 T . _ h2c CH- CH2 4-COOH xsz biotinylated DNA DNA probes labeled with biotin . . Biotinylated deoxyuridine triphosphate is incorporated into the molecule by nick translation . . The probe is then hybridized to the specimen such as denatured polytene chromosomes on a slide. The location of the biotin is visualized by complexing it with a streptavidin . molecule that is attached to a color-generating agent. The technique is less time consuming than autoradiography and gives greater resolution. See Appendix C 1981 Langer et al. biotron a group of rooms designed for the control of environmental factors singly and in combinations. Biotrons are used for producing uniform experimental organisms and for providing controlled conditions for experiments. biotype a physiologically distinct race within a species. If the biotype allows