See chaperone.参阅chaperone。...[继续阅读]

    One ofthe two divisions of the AUTONOMIC NER-VOUS SYSTEM,which supplies motornerves to the smooth muscles of the internalorgans and to cardiac muscles. Parasympa-thetic fibers emerge from the central nervoussystem via cranial nerves,especially the va-gus ...[继续阅读]

    USbiochemist and endocrinologist who isolated thefemale sex hormones estradiol,estriol,and es-trone. Doisy also isolated a principle named vi-tamin K2(now termed menaquinone) and wasable to characterize vitamins K1 and K2. Hewas awarded the Nobel Prize fo...[继续阅读]

    A cell capable of fusing with anoth-er cell to produce a ZYGOTE,from which anew individual organism can develop. Thefemale and male gametes of a particularspecies can have similar structure and behav-ior (isogametes),as in many simple organ-isms,but they ...[继续阅读]

    An enclosed cylindrical tract ofnerve fibers that forms a central route for theconduction of nerve impulses within thebody;for example,the spinal cord in verte-brates and other chordates.一个封闭的圆柱状的神经纤维形成的中枢神经通路。其作用是传递机体内的神经冲动,例如...[继续阅读]

    A peptide hormone produced by the anteri-or pituitary gland in vertebrates. It has amarked action on pigmentation in the skin of amphibians and reptiles,but its physiologicalrole in mammals is unclear.(MSH) 一种在脊椎动物中由腺垂体产生的肽类激素。对两栖类和爬行类动物皮肤...[继续阅读]

    In meiosis,the stage in mid-prophase I that is characterized by the con-traction of paired homologous chromosomes.At this point each chromosome consists of apair of chromatids,and the two associatedchromosomes are termed a tetrad.减数分裂中的中前期Ⅰ阶段。该阶段的特征是成对的同源...[继续阅读]

    See nuclear magnetic resonance.参阅nuclear magnetic reso-nance。...[继续阅读]

    American protein chemist. He was awardedthe Nobel Prize for chemistry jointly with S.Moore in 1972 for their contribution to theunderstanding of the connection betweenchemical structure and catalytic activity ofthe active center of the ribonucleasemolecul...[继续阅读]

    1.A‘back-up’mechanismthat helps to regulate gene expression in bac-terial OPERONS. An operon has a leader se-quence,which lies downstream of theoperons promotor and operator sites,but be-fore the start of the structural genes. An at-tenuator site is a seg...[继续阅读]