Bilingual word

双语生物化学词汇 Glossary of Biochemistry Bilingually

李关荣

编

西 南 大 学

Activity[Ak5tiviti]（活度，活性） The true thermodynamic

A Absolute configuration[5Abs[lu:t kEn9fi^jU5reiF[n]（绝 对构型） The configuration of four different substituent groups around an asymmetric carbon atom, in relation to D- and L-glyceraldehyde.

activity or potential of a substance, as distinct from its molar concentration.

Activity coefficient [Ak5tiviti

kEui5fiF[nt]（活度系数）

The factor by which the numerical value of the concentration of a solute must be multiplied to give its true

Absorption[[b5sR:pF[n] （ 吸 收 ） : transport of the

thermodynamic activity.

products of digestion from the intestinal tract into the

Adenosine[[5den[si:n] 3',5'-cyclic monophosphate: See

blood.

cyclic AMP.

Acceptor control [[k5sept（[）r

k[n5trol] （受体控

Adenosine diphosphate: See ADP.

制）: The regulation of the rate of respiration by the

Adenosine triphosphate: See ATP.

availability of ADP as phosphate group acceptor.

Adipocyte [5Adip[usait] （脂肪细胞）An animal cell

Accessory pigments [Ak5ses[ri 5pi^m[nt]（辅助色素）:

specialized for the storage of fats (triacylglycerols).

Visible light-absorbing pigments (carotenoids, xanthophyll, and phycobilins 藻 胆 素) in plants and photosynthetic bacteria that complement chlorophylls in trapping energy from sunlight.

Adipose[5Adip[us] tissue:（脂肪组织）Connective tissue specialized

for

the

storage

of

large

amounts

of

triacylglycerols.

ADP

(adenosine

diphosphate):

A

ribonucleoside

Acidosis[7Asi5d[usis]（酸中毒）: A metabolic condition in

diphosphate serving as phosphate group acceptor in the cell

which the capacity of the body to buffer is diminished;

energy cycle.

usually accompanied by decreased blood pH.

Aerobe[5ZEr[ub]（需氧生物） An organism that lives in

Actin[5Aktin]（肌动蛋白）: A protein making up the thin

air and uses oxygen as the terminal electron acceptor in

filaments[5fil[m[nt]（细丝） of muscle; also an important

respiration.

component of the cytoskeleton of many eukaryotic cells.

Aerobic[9ei[5r[ubik] Requiring or occurring in the

Activation energy [Akti5veiF[n 5en[dVi] (ΔG*)（活化

presence of oxygen.

能）: The amount of energy (in joules) required to convert

Alcohol fermentation[7f[:men5teiF[n]（乙醇发酵） The

all the molecules in 1 mole of a reacting substance from the

anaerobic conversion of glucose to ethanol via glycolysis.

ground state to the transition state.

See also fermentation.

Activator[5Aktiveit[] （ 活 化 物 、 激 活 剂 ） (1) A

Aldose[5Ald[us] （醛糖）A simple sugar in which the

DNA-binding

carbonyl carbon atom is an aldehyde; that is, the carbonyl

protein

that

positively

regulates

the

expression of one or more genes; that is, transcription rates

carbon is at one end of the carbon chain.

increase when an activator is bound to the DNA. (2) A

Alkalosis[7Alk[5l[usis]（碱中毒） A metabolic condition

positive modulator of an allosteric enzyme.

in which the capacity of the body to buffer is diminished;

Active site[5Aktiv sait]（活性部位） The region of an

usually accompanied by an increase in blood pH.

enzyme surface that binds the substrate molecule and

Allosteric enzyme[9Al[5sterik 5enzaim]（变/别构效应）

catalytically transforms it; also known as the catalytic site.

A regulatory enzyme, with catalytic activity modulated by

Active transport [5Aktiv trAns5pR:t] （ 主 动 运 输 ）

the noncovalent binding of a specific metabolite at a site

Energy-requiring transport of a solute across a membrane

other than the active site.

in the direction of increasing concentration.

Allosteric protein[5pr[uti:n] （变/别构蛋白） A protein

(generally

with

multiple

subunits)

with

multiple

Ampholyte[9Amf[lait]（两性电解质） A substance that

ligand-binding sites, such that ligand binding at one site

can act as either a base or an acid.

affects ligand binding at another.

Amphoteric[9Amf[5terik]（两性的） Capable of donating

Allosteric site （变/别构部位） The specific site on the

and accepting protons, thus able to serve as an acid or a

surface of an allosteric enzyme molecule to which the

base.

modulator or effector molecule is bound.

Anabolism[[5nAb[lizm] （ 合 成 代 谢 ） The phase of

α helix [5hi:liks]（α-螺旋）A helical conformation of a

intermediary

polypeptide chain, usually right-handed, with maximal

energy-requiring biosynthesis of cell components from

intrachain hydrogen bonding; one of the most common

smaller precursors.

secondary structures in proteins.

Anaerobe[A5nei[r[ub]（厌氧生物） An organism that

Ames[eimz] test: A simple bacterial test for carcinogens, based on the assumption that carcinogens are mutagens.

enzymatic esterification of the carboxyl group of an amino acid to the 3'-hydroxyl group of its corresponding tRNA.

with

the

lives without oxygen. Obligate anaerobes（专性厌氧生物）

Anaerobic[7Anei[5r[Ubik]（厌氧的）Occurring in the absence of air or oxygen.

Anaplerotic[AnQplE5rRnik]reaction: （回 补 反 应 ）An

an

Amino-substituted carboxylic acids, the building blocks of proteins.

Amino-terminal residue[5rezidju:]（氨基末端残基） The only amino acid residue in a polypeptide chain with a free a-amino group; defines the amino terminus of the polypeptide.

Aminoacyl-tRNA: （氨酰tRNA）An aminoacyl ester of a tRNA. Aminoacyl-tRNA synthetases: （氨酰tRNA合成酶） Enzymes that catalyze synthesis of an aminoacyl-tRNA at the expense of ATP energy.

Aminotransferases[[7mi:n[U5trAnsf[7reis]（氨基转移 酶） Enzymes that catalyze the transfer of amino groups fromα-amino to α-keto acids; also called transaminases.

Ammonotelic[7Am[Un[5telik] （ 排 氨 的 ） Excreting excess nitrogen in the form of ammonia.

Amphibolic pathway[9Amfi5bClik 5pB:Wwei] （双向代谢 途径）A metabolic pathway used in both catabolism and anabolism.

Amphipathic[9Amfi5pAWik]（双亲的）Containing both polar and nonpolar domains.

concerned

die when exposed to oxygen.

Amino acid activation（氨基酸活化）ATP-dependent

Amino acids[5Amin[U 5Asidz] （ 氨 基 酸 ）

metabolism

enzyme-catalyzed reaction that can replenish the supply of intermediates in the citric acid cycle.

Angstrom[5ANstr[m] (Ǻ) （埃）A unit of length (10-8cm) used to indicate molecular dimensions.

Anhydride[An5haidraid]（酸酐） The product, of the condensation of two carboxyl or phosphate groups in which the elements of water are eliminated to form a compound with the general structure R—X—O—X—R, where X is either carbon or phosphorus.

Anion[5Anai[n]-exchange resin[5rezin]（阴离子交换树 脂） A polymeric resin with fixed cationic groups; used in the chromatographic separation of anions.

Anomer[5einEum[] （ 异 头 物 、 端 基 异 构 体 ） Two stereoisomers of a given sugar that differ only in the configuration about the carbonyl (anomeric) carbon atom.

Antibiotic[7Antibai5Rtik] （ 抗 生 素 ） One of many different organic compounds that are formed and secreted by various species of microorganisms and plants, are toxic to other species, and presumably have a defensive function.

Antibody[7Anti7bRdi] （ 抗 体 ）

A defense protein

synthesized by the immune system of vertebrates. See also immunoglobulin.

Anticodon [7Anti5k[Ud[n] （ 反 密 码 子 ） A specific

coupling endergonic and exergonic reactions.

sequence of three nucleotides in a tRNA, complementary

ATP synthase[5sin Weis]（ATP合酶）An enzyme complex

to a codon for an amino acid in an mRNA.

that forms ATP from ADP and phosphate during oxidative

Antigen[7AntidV[n] （ 抗 原 ） A molecule capable of

phosphorylation in the inner mitochondrial membrane or

eliciting the synthesis of a specific antibody in vertebrates.

the

Antiparallel[7Anti5pAr[lel]（反平行） Describing two linear polymers that are opposite in polarity or orientation.

Antiport[7AntipC:t] （ 反 向 转 运 ） Cotransport of two solutes across a membrane in opposite directions.

Apoenzyme[7Ap[U5enzaim] （ 酶 蛋 白 ） The protein portion of an enzyme, exclusive of any organic or inorganic cofactors or prosthetic groups that might be required for catalytic activity.

Apolipoprotein[7Ap[U5lip[u5pr[uti:n]（脱辅基脂蛋白） The protein component of a lipoprotein.

bacterial

plasma

membrane,

and

during

photophosphorylation in chloroplasts.

ATPase[5eitipeis]（ATP酶）An enzyme that hydrolyzes ATP to yield ADP and phosphate; usually coupled to some process requiring energy.

Attenuator[E5tenjJeitE]（弱化子）An RNA sequence involved in regulating the expression of certain genes; functions as a transcription terminator.

Autotroph[5R:tEutrRf]（自养生物） An organism that can synthesize its own complex molecules from very simple carbon and nitrogen sources, such as carbon dioxide and ammonia.

Apoprotein[7Ap[U5pr[uti:n] （脱辅基蛋白）The protein portion of a protein, exclusive of any organic or inorganic cofactors or prosthetic groups that might be required for activity.

Apoptosis[eipRp5tEUsis]（细胞凋亡） (app'-a-toe'-sis) Programmed cell death, in which a cell brings about its own death and lysis, signaled from outside or programmed in its genes, by systematically degrading its own

Auxin[5R:ksin]（植物生长素） A plant growth hormone.

Auxotrophicmutant.[5mju:tEnt](auxotroph[5R:ksEtrRf] ) （营养缺陷突变体） A mutant organism defective in the synthesis of a given biomolecule, which must therefore be supplied for the organism's growth.

Avogadro's number: The number of molecules in a gram molecular weight (a mole) of any compound (6.02 × 1023).

B

macromolecules.

Arrestin [E5restin]（抑制蛋白） A family of proteins that bind to the phosphorylated carboxyl-terminal region of

Back-mutation（回复突变） A mutation that causes a mutant gene to regain its wild-type base sequence.

serpentine receptors, preventing their interactions with G

Bacteriophage[bAk5ti[riEfeidV](phage[feidV]) （ 噬 菌

proteins and thereby terminating the signal through those

体）A virus capable of replicating in a bacterial cell.

receptors.

Basal metabolic rate: （基础代谢率）The rate of oxygen

Asymmetric[Asi5metrik] carbon atom: （不对称碳原

consumption by an animal's body at complete rest, long

子）A carbon atom that is covalently bonded to four

after a meal.

different groups and thus may exist in two different

Base pair（bp,碱基对） Two nucleotides in nucleic acid

tetrahedral configurations.

chains that are paired by hydrogen bonding of their bases;

ATP

(adenosine

triphosphate):

A

ribonucleoside

for example, A with T or U, and G with C.

5'-triphosphate functioning as a phosphate group donor in

β conformation[7kRnfR:5meiF[n]（β构象）、An extended,

the cell energy cycle; carries chemical energy between

zigzag arrangement of a polypeptide chain; a common

metabolic pathways by serving as a shared intermediate

secondary structure in proteins.

β oxidation[Rksi5deiFEn] （β氧化）Oxidative degradation

Buffer[5bQfE]（缓冲液）A system capable of resisting

of fatty acids into acetyl-CoA by successive oxidations at

changes in pH, consisting of a conjugate acid-base pair in

the β-carbon atom.

which the ratio of proton acceptor to proton donor is near

β-turn （ β 转 角 ） A type of secondary structure in

unity.

polypeptides consisting of four amino acid residues

C

arranged in a tight turn so that the polypeptide turns back

Calorie[5kAlEri]（卡 , 卡路 里 ） The amount of heat

on itself.

required to raise the temperature of 1.0 g of water from

Bilayer[9bai5leir]（双分子层） A double layer of oriented

14.5 to 15.5 °C. One calorie (cal) equals 4.18 joules (J).

amphipathic lipid molecules, forming the basic structure of

Calvin cycle:（Calvin循环） The cyclic pathway used by

biological membranes. The hydrocarbon tails face inward

plants to fix carbon dioxide and produce triose phosphates.

to form a continuous nonpolar phase.

cAMP: See cyclic AMP.

Bile salts（胆酸盐） Amphipathic steroid derivatives with

cAMP receptor protein (CRP): （cAMP受体蛋白）A

detergent properties, participating in digestion and

specific regulatory protein that controls initiation of

absorption of lipids.

transcription of the genes producing the enzymes required

Binding energy:（吸附能） The energy derived from

for a bacterial cell to use some other nutrient when glucose

noncovalent interactions between enzyme and substrate or

is lacking. Also called catabolite[kE5tAbElait]gene

receptor and ligand.

activator protein (CAP)，降解物基因活化蛋白.

Binding site: （结合部位）The crevice or pocket on a

CAP: See catabolite gene activator protein.

protein in which a ligand binds.

Biocytin[7bai[u5saitin]（生物胞素） The conjugate amino acid residue arising from covalent attachment of biotin, through an amide linkage, to a Lys residue.

Biomolecule[7bai[u5mRlikju:l]（生物分子） An organic compound normally present as an essential component of living organisms.

Biopterin[5bai[u7terin] （ 生 物 喋 呤 ） An enzymatic cofactor derived from pterin and involved in certain oxidation-reduction reactions.

Biosphere[5baiEsfi[]（生物圈）All the living matter on or in the earth, the seas, and the atmosphere.

Biotin[5baiEtin]（ 生 物 素 ） A vitamin; an enzymatic cofactor involved in carboxylation reactions.

Bond energy:（键能） The energy required to break a bond.

Branch migration[mai5greiF[n]（分支迁移） Movement of the branch point in branched DNA formed from two DNA molecules with identical sequences. See also Holliday intermediate.

Capsid[5kApsid]（衣壳） The protein coat of a virion or virus particle.

Carbanion[5kB:bEnaiEn] （ 碳 负 离 子 ） A negatively charged carbon atom.

Carbocation[7kB:bE5keiF[n]（碳正离子） A positively charged carbon atom; also called a carbonium ion.

Carbon-assimilation[E9simi5leiFEn] reactions:（碳同化 反应） Reaction sequences in which atmospheric CO2 is converted into organic compounds.

Carbon-fixation reaction:（固碳反应） The reaction catalyzed by rubisco during photosynthesis, or by other carboxylases, in which atmospheric CO2 is initially incorporated into an organic compound.

Carboxyl-terminal residue:（羧基末端残基） The only amino acid residue in a polypeptide chain with a free a-carboxyl group; defines the carboxyl terminus of the polypeptide.

Carotenoids[kE5rRtEnRidz]（类葫罗卜素） Lipid-soluble photosynthetic pigments made up of isoprene units.

Catabolism[kE5tAbElizEm]（分解代谢） The phase of

Chiral [5tFir[l] center: （ 手 性 中 心 ） An atom with

intermediary

substituents arranged so that the molecule is not

metabolism

concerned

with

the

energy-yielding degradation of nutrient molecules.

superimposable on its mirror image.

Catabolite gene activator protein (CAP): See cAMP

Chiral compound: （手性化合物） A compound that

receptor protein.

contains an asymmetric center (chiral atom or chiral center)

Catalytic[7kAtE5litik] site（催化部位）See active site.

and thus can occur in two nonsuperimposable mirror-image

Catecholamines[9kAti5kEulEmi:n] （ 儿 茶 酚 胺 类 ）

forms (enantiomers).

Hormones, such as epinephrine, that are amino derivatives

Chlorophylls[5klR:rEfil] （ 叶 绿 素 ） A family of green

of catechol.

pigments functioning as receptors of light energy in

Catenane[5kAtnein] （ 连 环 体 ） Circular polymeric

photosynthesis; magnesium-porphyrin complexes.

molecules with a noncovalent topological link resembling

Chloroplasts

the links of a chain.

Chlorophyll-containing photosynthetic organelles in some

Cation[5kAtaiEn]-exchange resin: （阳离子交换树脂）

eukaryotic cells.

An insoluble polymer with fixed negative charges; used in

Chromatin[5krEumEtin] （ 染 色 质 ） A filamentous

the chromatographic separation of cationic substances.

complex of DNA, histones, and other proteins, constituting

cDNA: See complementary DNA.

the eukaryotic chromosome.

Central dogma[5dRgm[]（中心法则） The organizing

Chromatography[7krEumE5tRgr[fi]（层析） A process in

principle of molecular biology: genetic information flows

which complex mixtures of molecules are separated by

from DNA to RNA to protein.

many repeated partitionings between a flowing (mobile)

Centromere[5sentrE7miE]（着丝粒） A specialized site

phase and a stationary phase.

within a chromosome, serving as the attachment point for

Chromosome[5kEumEsEum]（染色体） A single large

the mitotic or meiotic spindle.

DNA molecule and its associated proteins, containing

Cerebroside[5seribrEusaid]( 脑 苷 酯 )

Sphingolipid

[5klR:rEplB:st]

（

叶

绿

体

）

many genes; stores and transmits genetic information.

containing one sugar residue as a head group.

Chylomicron[9kailEu5maikrRn]（乳糜微粒）A plasma

Channeling[5tFAnEliN]（生物合成途径限制作用) The

lipoprotein consisting of a large droplet of triacylglycerols

direct transfer of a reaction product (common intermediate)

stabilized by a coat of protein and phospholipid; carries

from the active site of one enzyme to the active site of a

lipids from the intestine to the tissues.

different enzyme catalyzing the next step in a sequential

cis and trans isomers: （顺反异构体）See geometric

pathway.

isomers.

Chemiosmotic coupling[9kemiRz5mRtik 5kQpliN]（化学

Cistron[5sistrRn]（顺反子） A unit of DNA or RNA

渗透偶联） Coupling of ATP synthesis to electron transfer

corresponding to one gene.

via an electrochemical H+ gradient across a membrane.

Citric acid cycle[5sitrik 5Asid 5saikl]（柠檬酸循环）A

Chemotaxis[7kemE5tAksis]（向化性）: A cell's sensing of

cyclic system of enzymatic. reactions for the oxidation of

and movement toward, or away from, a specific chemical

acetyl residues to carbon dioxide, in which formation of

agent.

citrate is the first step; also known as the Krebs cycle or

Chemotroph[7kemE5trRf]（化能生物） An organism that

tricarboxylic acid cycle.

obtains energy by metabolizing organic compounds

Clones[klEJn]（克隆） The descendants of a single cell.

derived from other organisms.

Cloning: The production of large numbers of identical

DNA molecules, cells, or organisms, from a single

inhibitor generally competes with the normal substrate or

ancestral DNA molecule, cell, or organism.

ligand for a protein's binding site.

Closed system （封闭系统）A system that exchanges

Complementary[kRmplE5mentEri]（互补的） Having a

neither matter nor energy with the surroundings. See also

molecular surface with chemical groups arranged to

system.

interact specifically with chemical groups on another

Cobalamin[kEu5bRlEmin]（钴胺素） See cocnzyme B12.

molecule.

Codon: （ 密 码 子 ） A sequence of three adjacent

Complementary DNA (cDNA) A DNA used in DNA

nucleotides in a nucleic acid that codes for a specific amino

cloning,

acid.

complementary to a given mRNA.

Coenzyme[kEu5enzaim]（辅酶） An organic cofactor

Configuration[kEn7figju5reiFEn] （ 构 型 ） The spatial

required for the action of certain enzymes; often contains a

arrangement of an organic molecule that is conferred by

vitamin as a component.

the presence of either (1) double bonds, about which there

Coenzyme A（辅酶A） A pantothenic acid（泛酸） -containing coenzyme serving as an acyl group carrier in certain enzymatic reactions.

Coenzyme B12(辅酶B12) An enzymatic cofactor derived

usually

made

by

reverse

transcriptase;

is no freedom of rotation, or (2) chiral centers, around which substituent groups are arranged in a specific sequence.

Configurational

isomers

cannot

be

interconverted without breaking one or more covalent

B

from the vitamin cobalamin, involved in certain types of carbon skeletal rearrangements.

Cofactor[kEu5fAktE](辅助因子) An inorganic ion or a coenzyme required for enzyme activity.

Cognate[5kRgneit]（相关的）Describing two biomolecules that normally interact; for example, an enzyme and its normal substrate, or a receptor and its normal ligand.

Cohesive ends [kEu5hi:siv endz]（粘性末端）See sticky ends.

Cointegrate[kEu5inti9greit]（共整合） An intermediate in the migration of certain DNA transposons in which the donor DNA and target DNA are covalently attached.

Colligative[5kRligEtiv] properties（依数性） Properties of solutions that depend on the number of solute particles per unit volume; for example, freezing-point depression.

Common intermediate[7intE5mi:djEt]（共同中间产物） A chemical compound common to two chemical reactions, as a product of one and a reactant in the other.

Competitive inhibition[kEm5petitiv 7inhi5biFEn]（竞争 性抑制作用） A type of enzyme inhibition reversed by increasing the substrate concentration; a competitive

bonds.

Conformation[7kRnfR:5meiFEn] （ 构 象 ） The spatial arrangement, of substituent groups that are free to assume different positions in space, without breaking any bonds, because of the freedom of bond rotation.

Conjugate[5kRndVUgit] acid-base pair:（共扼酸碱对） A proton donor and its corresponding deprotonated species; for example, acetic acid (donor) and acetate (acceptor).

Conjugate redox[5redRks] pair: （共扼氧还对） An electron donor and its corresponding electron acceptor form; for example, Cu+ (donor) and Cu2+ (acceptor), or NADH (donor) and NAD+ (acceptor).

Conjugated protein（结合蛋白质） A protein containing one or more prosthetic groups.

Consensus sequence[kEn5sens[s 5si:kwEns]（一致序 列） A DNA or amino acid sequence consisting of the residues that occur most commonly at each position within a set of similar sequences.

Conservative substitution[kEn5sE:vEtiv 7sQbsti5tju:FEn] （保守性置换） Replacement of an amino acid residue in a polypeptide by another residue with similar properties; for example, substitution of Glu by Asp.

Constitutive enzymes[5kRnstitjU:tiv 5enzaim]（组成酶）

small secreted proteins (such as interleukins or interferons)

Enzymes required at all times by a cell and present at some

that activate cell division or differentiation by binding to

constant level; for example, many enzymes of the central

plasma membrane receptors in sensitive cells.

metabolic pathways. Sometimes called house-keeping

Cytokinesis[7satEUkai5ni:sis] （ 胞 质 分 裂 ） The final

enzymes.

separation of daughter cells following mitosis.

Contour length[5kRntu[ lenW] (外形长度) The length of

Cytoplasm[5sait[UplAzm]（细胞质） The portion of a

a helical polymeric molecule as measured along the

cell's contents outside the nucleus but within the plasma

molecule's helical axis.

membrane; includes organelles such as mitochondria.

Corticosteroids[7kRtkEu5stiErRidz]（皮质类固醇激素）

Cytoskeleton[5sait[U5skelitEn] （ 细 胞 骨 架 ）

Steroid hormones formed by the adrenal cortex.

filamentous network providing structure and organization

Cotransport[kEU5trAnspR:t]（协同转运，共转运） The

to the cytoplasm; includes actin filaments, microtubules,

simultaneous transport, by a single transporter, of two

and intermediate filaments.

solutes across a membrane. See antiport, symport.

Cytosol[5saitEUsRl]（细胞浆） The continuous aqueous

Coupled reactions（偶联反应） Two chemical reactions

phase of the cytoplasm, with its dissolved solutes; excludes

that have a common intermediate and thus a means of

the organelles such as mitochondria.

The

D

energy transfer from one to the other.

Covalent bond[kEu5veilEnt bRnd]（共价键）A chemical

Dalton:（道尔顿） The weight of a single hydrogen atom

bond that involves sharing of electron pairs.

(1.66 x I0-24 g).

Cristae[5kristE]（嵴）Infoldings of the inner mitochondrial

Dark reactions:（暗反应） See carbon-assimilation

membrane.

reactions.

CRP（cAMP受体蛋白）See cAMP receptor protein.

De novo pathway [di:5nEJvEJ 5pB:Wwei]（从头合成）

Cyclic AMP (cAMP): A second messenger within cells;

Pathway for synthesis of a biomolecule, such as a

its formation by adenylyl cyclase is stimulated by certain

nucleotide, from simple precursors; as distinct from a

hormones or other molecular signals.

salvage pathway.

Cyclic electron flow:（循环电子流） In chloroplasts, the

Deamination[di:7Ami5neiFEn] （ 脱 氨 基 作 用 ） The

light-induced flow of electrons originating from and

enzymatic removal of amino groups from biomolecules

returning to photosystem I.

such as amino acids or nucleotides.

Cyclicphotophosphorylation[5saiklik

Degenerate code[di5dVen[reit kEUd]（兼并密码） A

7fEUtEUfRsfEri5lPiFEn]（循环光合磷酸化） ATP synthesis

code in which a single element in one language is specified

driven by cyclic electron flow through photosystem I.

by more than one element in a second language.

Cyclin[saiklin]（细胞周期蛋白） One of a family of

Dehydrogenases[di:5haidrEdVE7neis] （ 脱 氢 酶 类 ）

proteins that activate cyclin-dependent protein kinases and

Enzymes catalyzing the removal of pairs of hydrogen

thereby regulate the cell cycle.

atoms from their substrates.

Cytochromes[5saitEUkrEUm]（细胞色素） Heme proteins

Deletion mutation[di5li:FEn mjU5teiFEn]（删除突变）

serving as electron carriers in respiration, photosynthesis,

A mutation resulting from the deletion of one or more

and other oxidation-reduction reactions.

nucleotides from a gene or chromosome.

Cytokine[5saitEukin]（细胞因子） One of a family of

Denaturation[di:neitFE5reiFEn] （ 变 性 ）

Partial or

complete unfolding of the specific native conformation of a

polypeptide chain, protein, or nucleic acid.

each type.

Denatured protein[di:5neitFEd 5prEUti:n]（变性蛋白）

Dipole[5daipEUl]（双极分子） A molecule having both

A protein that has lost its native conformation by exposure

positive and negative charges.

to a destabilizing agent such as heat or detergent.

Diprotic acid[dai5prEUtik 5Asid] An acid having two

Deoxyribonucleic acid; See DNA.

dissociable protons.

Deoxyribonucleotides[di:5Rksi9raib[J5njU:kliEtaid]（脱

Disaccharide[dai5sAkEraid] （ 二 糖 ） A carbohydrate

氧核糖核苷酸） Nucleotides containing 2-deoxyribose as

consisting of two covalently joined monosaccharide units.

the pentose component.

Dissociation constant[di7sEUFi5eiFEn 5kRnstEnt]（解离

Desaturases[disAtFEreisis]（去饱和酶） Enzymes that

常数）

catalyze the introduction of double bonds into the

dissociation of a complex of two or more biomolecules into

hydrocarbon portion of fatty acids.

its components; for example, dissociation of a substrate

Desolvation[di:zRl5veiFEn]（脱水） In aqueous solution,

from an enzyme. (2) The dissociation constant (Ka) of an

the release of bound water surrounding a solute.

acid, describing its dissociation into its conjugate base and

Dextrorotatory isomer[5dekstrEU5rEUtEtEri 5aisEUmE]

a proton.

（右旋异构体） A stercoisomer that rotates the plane of

Disulfide bridge[dai5sQlfaid bridV] (二硫桥)A covalent

plane-polarized light clockwise.

cross link between two polypeptide chains formed by a

Diabetes mellitus[7daiE5bi:ti:z melitEs] （糖尿病） A

cystine residue (two Cys residues).

metabolic disease resulting from insulin deficiency;

DNA (deoxyribonucleic acid) A polynucleotide having a

characterized by a failure in glucose transport from the

specific sequence of deoxyribonucleotide units covalently

blood into cells at normal glucose concentrations.

joined through 3', 5'-phosphodiester bonds; serves as the

Dialysis[dai5Alisis]（透析）Removal of small molecules

carrier of genetic information.

from a solution of a macromolecule, by allowing them to

DNA chimera[kai5miErE] （ DNA 嵌 合 ）

diffuse through a semipermeable membrane into water.

containing genetic information derived from two different

Differential

species.

centrifugation

[7difE5renFEl

(1) An equilibrium constant (Kd)for the

A DNA

sen7trifju5geiFEn] （ 差 速 离 心 ） Separation of cell

DNA cloning: Sec cloning.

organelles or other particles of different size by their

DNA library:（DNA文库） A collection of cloned DNA

different rates of sedimentation in a centrifugal field.

fragments.

Differentiation[7difE7renFi5eiFEn]（分化） Specialization

DNA ligase[li5geis]（DNA连接酶） An enzyme that

of cell structure and function during embryonic growth and

creates a phosphodiester bond between the 3' end of one

development.

DNA segment, and the 5' end of another.

Diffusion[di5fjU:VEn]（扩散 ） The net movement, of

DNA looping[lU:piN] （DNA出环）The interaction of

molecules in the direction of lower concentration.

proteins bound at distant sites on a DNA molecule so that

Digestion[di5dVestFEn]（消化） Enzymatic hydrolysis of

the intervening DNA forms a loop.

major nutrients in the gastrointestinal system to yield their simpler components.

Diploid[5diplRid]（二倍体） Having two sets of genetic information; describing a cell with two chromosomes of

DNA microarray（DNA微阵列） A collection of DNA sequences immobilized on a solid surface, with individual sequences laid out in patterned arrays that can be probed by hybridization.

DNA polymerase[5pRlimE7reis] （ DNA 聚 合 酶 ） An

enzyme that catalyzes template-dependent synthesis of

Electron acceptor（电子受体） A substance that receives

DNA

electrons in an oxidation-reduction reaction.

from

its

deoxyribonucleoside

5'-triphosphate

precursors.

Electron carrier（ 电 子载体 ） A protein, such as a

DNA replicase[5replikeis] system（DNA复制酶系统）

flavoprotein or a cytochrome, that can reversibly gain and

The entire complex of enzymeH and specialized proteins

lose electrons; functions in the transfer of electrons from

required in biological DNA replication.

organic nutrients to oxygen or some other terminal

DNA supercoiling[5sjU:pE7kRiliN]（DNA超螺旋化） The

acceptor.

coiling of DNA upon itself, generally as a result of bending,

Electron donor（电子供体） A substance that donates

underwinding, or overwinding of the DNA helix.

electrons in an oxidation-reduction reaction.

DNA transposition[7trAnsp[5ziFEn]（DNA转座） See transposition.

Electron transfer（电子转移） Movement of electrons from substrates to oxygen via the carriers of the respiratory

Domain[dEu5mein]（结构域） A distinct structural unit of

(electron transfer) chain.

a polypeptide; domains may have separate functions and

Electrophile[i7lektrEfail]（亲电剂） An electron-deficient

may fold as independent, compact units.

group with a strong tendency to accept electrons from an

Double helix（双螺旋） The natural coiled conformation of two complementary, antiparallel DNA chains.

Electrophoresis[i7lektrEfE5ri:sis]（电泳） Movement of

Double-reciprocal[ri5siprEkEl] plot:（双倒数作图） A plot, of 1/Vo versus 1/[S], which allows a more accurate determination of Vmax and Km than a plot of V versus [S]; also called the Lineweaver-Burk plot,

common bacterium found in the small intestine of vertebrates; the most well-studied organism.

Electrochemical gradient[i7lektrEJ5kmikEl 5greidiEnt] （电化学梯度） The sum of the gradients of concentration and of electric charge of an ion across a membrane; the oxidative

phosphorylation

and

photophosphorylation.

Electrochemical potential[i7lektrEJ5kmikEl pE5tenFEl] （电化学势）

Electroporation[i7lektrEpR:reiFEn] （ 电 穿 孔 法 ）

high-voltage pulse.

E. coli[i: 5kEUlai] (Escherichia coli): （大肠杆菌）A

for

to separate mixtures of ions, proteins, or nucleic acids.

the cells transiently permeable by the application of a

E'°: 标准还原电位 See standard reduction potential.

force

charged solutes in response to an electrical field; often used

Introduction of macromolecules into cells after rendering

E

driving

electron-rich group (nucleophile).

The energy required to maintain a

separation of charge and of concentration across a membrane.

Electrogenic[i7lektrE5dVenik]（生电的）Contributing to an electrical potential across a membrane.

Elongation[7i:lRN5geiFEn] factors（延长因子） Specific proteins required in the elongation of polypeptide chains by ribosomes.

Eluate[5PljUit] （ 流 出 液 ）

The effluent from a

chromatographic column.

Enantiomers[i5nAntiEUmE] （ 对 映 异 构 体 ） Stereoisomers that are nonsuperimposable mirror images of each other.

End-product inhibition: See feedback inhibition.

Endergonic[7endE5gRnik] reaction( 耗 能 反 应 ): A chemical reaction that consumes energy (that is, for which ΔG is positive).

Endocrine glands[5endEUkrain glAnd]（内分泌腺） Groups of cells specialized to synthesize hormones and secrete them into the blood to regulate other types of cells.

Endocytosis[5endEUsai5tEUsis]（内吞体） The uptake of

of reactions, often involved in regulatory events, in which

extracellular material by its inclusion within a vesicle

one enzyme activates another (often by phosphorylation),

formed by an invagination of the plasma membrane.

which activates a third, and so on. The effect, of a catalyst

Endonuclease[7endEU5njU:kli7eis]（ 内切核 酸酶 ） An

activating a catalyst is a large amplification of the signal

enzyme that hydrolyzes the interior phosphodiester bonds

that initiated the cascade.

of a nucleic acid; that is, it acts at points other than the

Epimerases[5epimE7reis] （ 表 异 构 酶 ） Enzymes that

terminal bonds.

catalyze the reversible interconveraion of two epimers.

Endoplasmic reticulum[5endEUplAzmik ri5tikjUlEm]

Epimers[5epimE] （ 表 异 构 体 ） Two stereoisomers

（内质网） An extensive system of double membranes in

differing in configuration at one asymmetric center, in a

the cytoplasm of eukaryotic cells; it encloses secretory

compound having two or more asymmetric centers.

channels and is often studded with ribosomes (rough

Epithelial [7epi5Wi:ljEl] cell（上皮细胞） Any cell that

endoplasmic reticulum).

forms part of the outer covering of an organism or organ.

Endothermic[7endEU5WV:mik]

reaction （吸热反应）

Epitope[5epitEUp] （ 抗 原 决 定 族 ）

An antigenic

A chemical reaction that takes up heat (that is, for which

determinant; the particular chemical group or groups

ΔH is positive).

within a macromolecule (antigen) to which a given

Energy charge（能荷） The fractional degree to which the

antibody binds.

ATP/ADP/AMP

Equilibrium[7i:kwi5libriEm]（平衡）The state of a system

system

is

filled

with

high-energy

phosphate groups.

in which no further net change is occurring; the free energy

Energy coupling（能量偶联） The transfer of energy from

is at a minimum.

one process to another.

Equilibrium constant (K'eq) （平衡常数）A constant,

Enhancers[in5hB:nsE] （增强子）DNA sequences that

characteristic for each chemical reaction; relates the

facilitate the expression of a given gene; may be located a

specific concentrations of all reactants and products at

few hundred, or even thousand, base pairs away from the

equilibrium at a given temperature and pressure.

gene.

Erythrocyte[i5riWrEUsait]（红细胞） A cell containing

Enthalpy (H)[5PnWAlpi]（焓） The heat. content of a

large amounts of hemoglobin and specialized for oxygen

system.

transport; a red blood cell.

Enthalpy change (ΔH) （ 焓 变 ） For a reaction, is

Escherichia coli[7eFE5rikiE

approximately equal to the difference between the energy

Essential[i5senFEl] amino acids（必需氨基酸） Amino

used to break bonds and the energy gained by the

acids that cannot be synthesized by humans (and other

formation of new ones.

vertebrates) and must be obtained from the diet.

Entropy (S)[5entrEpi]（熵） The extent of randomness or

Essential fatty acids （ 必 需 脂 肪 酸 ） The group of

disorder in a system.

polyunsaturated fatty acids produced by plants, but not by

Enzyme[5enzaim]（酶） A biomolecule, either protein or

humans; required in the human diet.

RNA, that catalyzes a specific chemical reaction. It does

Ethanol fermentation[5eWEnR:l 7fE:men5teiFEn]（乙醇发

not affect the equilibrium of the catalyzed reaction; it

酵） See alcohol fermentation.

enhances the rate of a reaction by providing a reaction path

Eukaryote[jU5kAriEUt]（真核生物） A unicellular or

with a lower activation energy.

multicellular

Enzyme cascade[5enzaim kAs5keid]（酶级联） A series

membrane-bounded nucleus, multiple chromosomes, and

organism

5kEUlai]See E. coli.

with

cells

having

a

internal organelles.

metabolic sequence by the end product of the sequence;

Excited state（激发态） An energy-rich state of an atom or

also known as end-product inhibition.

molecule; produced by the absorption of light energy.

Fermentation[7fE:men5teiFEn]（发酵）Knergy-yielding A

anaerobic breakdown of a nutrient molecule, such as

chemical reaction that proceeds with the release of free

glucose, without net oxidation; yields lactate, ethanol, or

energy (that is, for which ΔG is negative).

some other simple product.

Exocytosis[7eksEUsai5tEUsis]（胞泌作用） The fusion of

Fibroblast[5faibrEUblB:st]（成纤维细胞） A cell of the

an intracellular vesicle with the plasma membrane,

connective tissue that secretes connective tissue proteins

releasing the vesicle contents to the extracellular space.

such as collagen.

Exon[eksRn]（外显子） The segment of a eukaryotic gene

Fibrous[5faibrEs] proteins（纤维状蛋白质） Insoluble

that encodes a portion of the final product of the gene; a

proteins that serve in a protective or structural role; contain

portion that remains after posttranscriptional processing

polypeptide chains tliat generally share a common

and is transcribed into a protein or incorporated into the

secondary structure.

structure of an RNA. See intron.

Fingerprinting[5fiNgEprintiN]（指纹作图）See peptide

Exonuclease[7eksEU5njU:klieis] （ 外 切 核 酸 酶 ） An

mapping.

enzyme that hydrolyzes only those phosphodiester bonds

First law of thermodynamics[5WE:mEUdai5nAmiks]The

that are in the terminal positions of a nucleic acid.

law staling that in all processes, the total energy of the

Exothermic[7ksEJ5WV:mik] reaction:（放热反应） A

universe remains constant.

chemical reaction that releases heat (that is, for which A//

Fischer projection formulas: （ Fischer 投 影 式 ） See

is negative).

projection formulas.

Expression vector[5vektE]（表达载体） See vector.

5' end: The end of a nucleic acid that lacks a nucleotide

Exergonic[7eksE5gRnik] reaction （ 放 能 反 应 ）

bound at the 5' position of the F

terminal residue.

Facilitated diffusion[fE5siliteitid di5fjU:VEn] （协助扩

Flagellum[fl[5dVelEm](鞭毛 )A cell appendage used in

散）Diffusion of a polar substance across a biological

propulsion. Bacterial flagella have a much simpler

membrane through a protein transporter; also called

structure than eukaryotic flagella, which are similar to

passive diffusion or passive transport.

cilia.

Facultative[5fAkEltEtiv] cells（兼性需样氧细胞）Cells

Flavin

that can live in the presence or absence of oxygen.

Dehydrogenases requiring one of the riboflavins.

FAD (flavin adenine dinucleotide)[5fleivin 5AdEni:n

coenzymes, FMN or FAD.

dai5njU:kliE7taid] （ 黄 素 腺 嘌 呤 二 核 苷 酸 ）

The

linked

dehydrogenases( 黄 素 脱 氢 酶 )

Flavin nucleotides（黄素核苷酸） Nucleotide coenzymes

coenzyme of some oxidation-reduction enzymes; it

(FMN and FAD) containing riboflavin.

contains riboflavin.

Flavoprotein[7fleivEU5prEUti:n](黄素蛋白 ) An enzyme

Fatty acid[5fAti 5Asid]（脂肪酸）A long-chain aliphatic

containing a flavin nucleotide as a tightly bound prosthetic

carboxylic acid found in natural fats and oils; also a

group.

component of membrane phospholipids arid glycolipids.

Fluid mosaic[mR5zeiik] model（流动镶嵌模型） A model

Feedback inhibition[5fi:dbAk 7inhi5bFEn]（反馈抑制）

describing biological membranes as a fluid lipid bilayer

Inhibition of an allosteric enzyme at the beginning of a

with embedded proteins; the bilayer exhibits both structural

and functional asymmetry.

enzyme-catalyzed cyclic reactions that results in release of

Fluorescence[flUE5resns]（荧光） Emission of light by

thermal energy by the hydrolysis of ATP. G

excited molecules as they revert to the ground state, FMN (flavin mononucleotide): （ 黄 素 单 核 苷 酸 ）

G proteins: （ G 蛋 白 ） A family of heterotrimeric

Riboflavin phosphate, a coenzyme of certain oxidation-

GTP-binding proteins that act in intracellular signaling

reduction enzymes.

pathways. Commonly, ligand binding to a serpentine

Footprinting[5fJtprintiN]( 足 迹 法 ) A technique for

receptor induces the exchange of GTP for bound GDP,

identifying the nucleic acid sequence bound by a DNA-or

enabling the G protein to activate a downstream enzyme in

RNA-binding protein.

a signaling pathway. G proteins have intrinsic GTPase

Fractionation[7frAkFE5neiFEn]（分级分离） The process of separating the proteins or other components of a

activity, and therefore self-inactivate. ΔG’°: (标准自由能变化) See standard free-energy change.

complex molecular mixture into fractions based on

Gametes[5gAmi:t]（配子） Reproductive cells with a

differences in their physical properties, such as size, net

haploid gene content; sperm or egg cells.

charge, and solubility.

Gangliosides[5gANgliEsaid] （ 神 经 节 苷 脂 ）

Frame shift（移码） A mutation caused by insertion or

Sphingolipids, containing complex oligosaccharides as

deletion of one or more paired nucleotides, changing the

head groups; especially common in nervous tissue.

reading frame of codons during protein synthesis; the

Gel filtration[dVel fil5treiFEn] （ 凝 胶 过 滤 ）

polypeptide product has a garbled amino acid sequence

size-exclusion chromatography.（分子排阻层析）

beginning at the mutated codon.

Gene[dVi:n]（基因）A chromosomal segment, that codes

Free energy (G)（自由能） The component of the total

for a single functional polypeptide chain or RNA molecule.

energy of a system that can do work at constant

Gene expression（基因表达） Transcription, and in the

temperature and pressure.

case of proteins, translation, to yield the product of a gene;

Free energy of activation ΔG‡ ( 活 化 自 由 能 ); See

a gene is expressed when its biological product is present

activation energy.

and active.

Free-energy change ΔG(自由能变化): The amount of

Gene splicing[dVi:n 5splaisiN] （ （ 基 因 拼 接 ） The

free energy released (negative ΔG) or absorbed (positive

enzymatic attachment of one gene, or part. of a gene, to

ΔG) in a reaction at constant temperature and pressure.

another.

Free radical[5rAdikEl]（自由基） See radical.

General acid-base catalysis[kE5tAlisis]（广义酸碱催化）

Functional group （功能团）The specific atom or group of

Catalysis involving proton transfer(s) to or from a

atoms that confers a particular chemical property on a

molecule other than water.

biomolccule.

Genetic code[dVi5netik kEUd]（遗传密码） The set of

Furanose[5fjUErE7nEUs] （ 呋 喃 糖 ） A simple sugar

triplet code words in UNA (or mRNA) coding for the

containing the five-membered furan ring.

amino acids of proteins.

Fusion[5fjU:VEn] protein（融合蛋白） (1) A family of

Genetic information （ 遗 传 信 息 ） The hereditary

proteins that facilitate membrane fusion. (2) The protein

information contained in a sequence of nucleotide bases in

product of a gene created by the fusion of two distinct

chromosomal DNA or RNA.

genes or portions of genes.

Genetic map（遗传图谱）A diagram showing the relative

Futile[5fjU:tail] cycle （ 无 效 循 环 ）

A set of

See

sequence and position of specific genes along a

chromosome.

glycolipids.

Genome[5dVi:nEUm] （ 基 因 组 ）

All the genetic

Glycolipid[7glaikE5lipid]（ 糖脂） A lipid containing a

information encoded in a cell or virus.

carbohydrate group,

Genomic library[5dVi:nEUmik 5laibrEri ]（基因组文库）

Glycolysis[glai5kRlisis]（糖酵解） The catabolic pathway

A DNA library containing DNA segments representing all

by which a molecule of glucose is broken down into two

(or most) of the sequences in an organism's genome.

molecules of pyruvate.

Genotype[5dVenEtaip]（基因性或遗传型） The genetic

Glycoprotein[glai5kEU5prEUti:n] ( 糖 蛋 白 ) A protein

constitution of an organism, as distinct from ils physical

containing a carbohydrate group.

characteristics, or phenotype.

Glycosaminoglycan[5glai5kEUsE5m:nEJ5glaikAn]（糖胺

Geometric isomers[dViE5metrik 5aisEUmE]（几何异构

聚糖） A heteropolysaccharide of two alternating units:

体） Isomers related by rotation about a double bond; also

one

called cis and trans isomers.

N-acetylgalactosamine; the other is a uronic acid (usually

Germ-line cell (生殖系细胞) A type of animal cell that is

glucuronic

formed early in embryogenesis and may multiply by

mucopolysaccharide[.(粘多糖)

mitosis or may produce, by meiosis, cells that develop into

Glycosidic[7glaikEJ5sidik] bonds （ 糖 苷 键 ） Bonds

gametes (egg or sperm cells).

between a sugar and another molecule (typically an alcohol,

Globular[5glRbjUlE] proteins（球蛋白） Soluble proteins

purine, pyrimidine, or sugar) through an intervening

with a globular (somewhat rounded) shape.

oxygen.

Glucogenic[glU:kE5dVenik] amino acids:（生糖氨基酸）

Glyoxylate[glai5Rksi7leit] cycle (乙醛酸循环) A variant

Amino acids with carbon chains that can be metabolically

of the citric acid cycle, for the net conversion of acetate

converted into glucose or glycogen via gluconeogenesis.

into succinate and, eventually, new carbohydrate; present

Gluconeogenesis[7glU:kE7ni:EU5dVenisis]( 糖 异 生 ) The

in bacteria and some plant cells.

biosynthesis

simpler,

Glyoxysome[7gli5RksEm] （ 乙 醛 酸 体 ） A specialized

as

peroxisome containing the enzymes of the glyoxylate cycle;

or

found in cells of germinating seeds.

of

noncarbohydrate

a

carbohydrate precursors

from such

oxaloacetate[7RksElEJ5Asiteit] （ 草 酰 乙 酸 ）

either

N-acetylglucosamine

acid).

Formerly

or called

Golgi complex（高尔基复合体）A complex membranous

pyruvate[pai5rU:veit]（丙酮酸）.

Glycan[5glaikAn] （ 聚 糖 ）

is

Another

term

for

organelle of eukaryotic cells; functions in the

polysaccharide; a polymer-of monosaccharide units joined

posttranslational modification of proteins and their

by glycosidic bonds,

secretion from the cell or incorporation into the plasma

Glycerophospholipid [^lisErEu7fCsfEU5lipid] （甘油磷 脂） An amphipathic lipid with a glycerol backbone; fatty acids are ester-linked to C-l and C-2 of glycerol, and a polar alcohol is attached through a phosphodiester linkage

Gram molecular weight（克分子重量） The weight in grams of a compound that is numerically equal to its molecular weight; the weight of 1 mole.

Grana[5greinE]（基粒） Stacks of thylakoids[5WailE7kRid]

to C-3.

Glycoconjugate[^laikEU55kRndVU^it]( 复 合 糖 )

membrane or organellar membranes.

A

（ 类 囊 体 ） , flattened membranous sacs or disks, in

compound containing a carbohydrate component bound

chloroplasts.

covalently to a protein or lipid, forming a glycoprotein or

Ground state（基态） The normal, stable form of an atom

or molecule; as distinct from the excited state.

sequences, often as a product of genetic recombination.

Group transfer potential（基团转移力） A measure of

Heteropolysaccharide[7hetErE7pRli5sAkEraid]（杂多糖）

the ability of a compound to donate an activated group

A polysaccharide containing more than one type of sugar.

(such as a phosphate or acyl group); generally expressed as

Heterotroph（异养生物）[7hetErEUtrRf] An organism that

the standard free energy of hydrolysis.

requires complex nutrient molecules, such as glucose, as a source of energy and carbon.

H Half-life （ 半 衰 期 ） The time required for the

Heterotropic[7hetErEUtrRpik]（异促的） Describes an

disappearance or decay of one-half of a given component

allosteric modulator that is distinct from the normal ligand.

in a system.

Heterotropic enzyme（异促酶）An allosteric enzyme

Haploid[5hAplRid]（ 单倍体） Having a single set of

requiring a modulator other than its substrate.

genetic

Hexose[5heks[Us] （ 己 糖 ） A simple sugar with a

information;

describing

a

cell

with

one

chromosome of each type.

backbone containing six carbon atoms.

Hapten[5hApten]（半抗原） A small molecule which,

High-energy compound（高能化合物）A compound that

when linked to a larger molecule, elicits an immune

on hydrolysis undergoes a large decrease in free energy

response.

under standard conditions.

Haworth perspective formulas:（Haworth透视式） A

High-performance

method for representing cyclic chemical structures so as to

chromatography[7krEUmE5tRgrEfi (HPLC)（高效液相色

define the configuration of each substituent group; the

谱 ） Chromatographic procedure, often conducted at

method commonly used for representing sugars.

relatively high pressures, using automated equipment that

Helicase[hilikeis](解螺旋酶) An enzyme that, catalyzes

permits refined and highly reproducible profiles,

the separation of strands in a DNA molecule before

Hill reaction（希尔反应） The evolution of oxygen and

replication.

the photoreduction of an artificial electron acceptor by a

Heme[hi:m]（血红素） The iron-porphyrin prosthetic

chloroplast preparation in the absence of carbon dioxide.

group of heme proteins.

Histones[5histEUn]（组蛋白） The family of five basic

Heme protein（血红素蛋白） A protein containing a heme

proteins that associate tightly with DNA in the

as a prosthetic group.

chromosomes of all eukaryotic cells,

Hemoglobin[7hi:mEU5glEUbin] （ 血 红 蛋 白 ） A heme

Holliday intermediate（赫利地中间物） An intermediate

protein in erythrocytes; functions in oxygen transport.

in genetic recombination in which two double-stranded

Henderson-Hasselbalch equation （ 亨 - 哈 方 程 ） An

DNA molecules are joined by virtue of a reciprocal

equation relating the pH, the pKa, and the ratio of the

crossover involving one strand of each molecule.

concentrations

Holoenzyme[7hRlEU5enzaim]（全酶） A catalytically

of

the

proton-acceptor

(A+)

and

enzyme

including

liquid

proton-donor (HA) species in a solution.

active

all

necessary

subunits,

Hepatocyte [5hepEtEsait](肝细胞) The major cell type of

prosthetic groups, and cofactors.

liver tissue.

Homeobox[7hEUmiEUbQks]（同源框） A conserved DNA

Heteroduplex[7hetErEU5djU:pleks] DNA ( 异 源 双 链

sequence of 180 base pairs encoding a protein domain

DNA) Duplex DNA containing complementary strands

found in many proteins that play a regulatory role in

derived from two different DNA molecules with similar

development.

Homeodomain[7hEUmiEU dEU5mein]（发育同源结构域）

Hyaluronic acid[haiEljU5rRnik 5Asid] （透明质酸） A

The protein domain encoded by the homeobox.

high molecular weight, acidic polysaccharide typically

Homeostasis[7hEUmiEU5steisis] （ 内 稳 态 ）

The

composed

of

the

alternating

disaccharide

maintenance of a dynamic steady state by regulatory

GlcUA(β1→3)GlcNAc, Hyaluronic acid is a major

mechanisms that compensate for changes in external

component of the extracellular matrix, and forms larger

circumstances.

complexes (proteoglycans) with proteins and other acidic

Homeotic[[5hEUmiEtik] genes（同源框基因）Genes that

polysaccharides.

regulate the development of the pattern of segments in the

Hydrogen bond（氢键）A weak electrostatic attraction

Drosophila body plan; similar genes are found in most

between one electronegative atom (such as oxygen or

vertebrates.

nitrogen) and a hydrogen atom covalently linked to a

Homologous[hR5mRlEgEs] genetic recombination（同源

second electronegative atom.

遗传重组） Recombination between two DNA molecules

Hydrolases[5haidrEleis]（水解酶） Enzymes (proteases,

of similar sequence, occurring in all cells; occurs during

lipases, phosphatases, nucleases, for example) that catalyze

meiosis and mitosis in eukaryotes.

hydrolysis reactions.

Homologous proteins （ 同 源 蛋 白 ） Proteins having

Hydrolysis[haidrRRlisis]（水解） Cleavage of a bond,

sequences and functions similar in different species; for

such as an anhydride or peptide bond, by the addition of

example, the hemoglobins.

the elements of water, yielding two or more products,

Homopolysaccharide[7hEUmEU5pRli5sAkEraid] （ 同 多

Hydronium[hai5drEUniEm] ion （ 水 合 氢 离 子 ） The

糖 ） A polysaccharide made up of only one type of

hydrated hydrogen ion (H3O+).

monosaccharide unit.

Homotropic[7hEUmEU5trRpik] ( 同 促 的 ） Describes an allosteric modulator that is identical to the normal ligand.

Homotropic enzyme:（同促酶） An allosteric enzyme that uses its substrate as a modulator.

Hormone[5hR:rmEUn]（激素） A chemical substance synthesized in small amounts by an endocrine tissue and carried in the blood to another tissue, where it acts as a messenger to regulate the function of the target tissue or organ.

Hormone receptor(激素受体) A protein in, or on the surface of, target cells that binds a specific hormone and initiates the cellular response, Hormone response element (HRE)（激素响应元件） A short (12 to 20 bp) DNA sequence to which receptors for steroid, retinoid, thyroid, and vitamin D hormones bind, altering the expression of the contiguous genes. For each hormone, there is a consensus sequence preferred by the cognate receptor.

Hydropathy[hai5drRpEWi]index:（亲水指数） A scale that expresses the relative hydrophobia and hydrophilic tendencies of a chemical group.

Hydrophilic[7haidrEU5filik]（亲水的） Polar or charged; describing molecules or groups that associate with (dissolve easily in) water.

Hydrophobic[7haidEJ5fEJbik] （ 疏 水 的 ） Nonpolar; describing molecules or groups that are insoluble in water. hydrophobic interactions （ 疏 水 相 互 作 用 ） The association of nonpolar groups, or compounds, with each other in aqueous systems, driven by the tendency of the surrounding

water

molecules

to

seek

their

most

stable(disordered)state.

Hyperchromic[7haipE5krEUmik] effect (增色效应) The large increase in light absorption at 260 nm occurring as a double- helical DNA is melted (unwound).

Hypoxia[haipEUksiE]（低氧） The metabolic condition in which the supply of oxygen is severely limited.

I

Insertion mutation（插入突变） A mutation caused by

Immune[i5mjU:n] response（免疫反应） The capacity of

insertion of one or more extra bases, or a mutagen,

a vertebrate to generate antibodies to an antigen, a

between successive bases in DNA.

macromolecule foreign to the organism.

Insertion sequence（插入序列） Specific base sequences

Immunoglobulin[i5mjU:nEU5glRbjUlin](免疫球蛋白) An

at either end of a transposable segment of DNA.

antibody protein generated against, and capable of binding

Integral[5intigrEl] proteins: （ 膜 整 体 蛋 白 ） Proteins

specifically to an antigen.

firmly bound to a membrane by hydrophobic interactions;

in vitro[in5vi:trEU]（体外） "In glass"; that is, in the

as distinct from peripheral proteins.

test tube.

Integrin[5intigrin]（整连蛋白） One of a large family of

in vivo[in5vi:vEu]（体内） "In life"; that is, in the

heterodimeric

living cell or organism.

adhesion of cells to other cells or to the extracellular

Induced fit （诱导契合）A change in the conformation of

matrix.

an enzyme in response to substrate binding that renders the

Intercatlating mutagen[in5tE:kEleitiN 5mjU:tEdVEn（嵌

enzyme catalytically active; also used to denote changes in

入突变） A mutagen that inserts itself between successive

the conformation of any macromolecule in response to

bases in a nucleic acid, causing a frame-shift mutation.

ligand binding such that the binding site of the

Intercalation[in5tE:kEleiFEn] （嵌入）Insertion between

macromolecule better conforms to the shape of the ligand.

stacked aromatic or planar rings; for example, the insertion

Indncer（诱导物） A signal molecule that, when bound to

of a planar molecule between two successive bases in a

a regulatory protein, produces an increase in the expression

nucleic acid.

of a given gene.

Interferons[7intE5fiErRn] （ 干 扰 素 ）

Induction （诱导） An increase in the expression of a

glycoproteins with antiviral activities.

gene in response to a change in the activity of a regulatory

Intermediary

protein.

me5tAbElizEm] （ 中 间 代 谢 ） In

Informational macromolecules: （ 信 息 大 分 子 ）

enzyme-catalyzed reactions that extract chemical energy

Biomolecules containing information in the form of

from nutrient molecules and utilize it to synthesize and

specific sequences of different monomers; for example,

assemble cell components.

many proteins, lipids, polysaccharides, and nucleic acids.

Intron [5intrRn](intervening sequence)（内含子，间隔序

Initiation codon[i7niFi5eiFEn 5kEUdEn] （ 起 始 密 码 ）

列 ） A sequence of nucleotides in a. gene that is

AUG (sometimes GUG in prokaryotes); codes for the first amino acid in a polypeptide sequence: N-formylmethionine in prokaryotes, and methionine in eukaryotes.

Initiation complex（ 起始复合物） A complex of a ribosome with an mRNA and the initiating Met-tRNAMet or fMet-tRNAMet, ready for the elongation steps.

Inorganic pyrophosphatase[pairE5fRsfEteis](无机焦磷 酸酶) An enzyme that hydrolyzes a molecule of inorganic pyrophosphate to yield two molecules of (ortho) phosphate; also known as pyrophosphatase.

transmembrane

proteins

metabolism

that

mediate

A class of [7intE5mi:diEri cells,

the

transcribed but excised before the gene is translated.

Ion channel[5aiEn

5tFAnl]（离子通道） An integral

protein that provides for the regulated transport of a specific ion, or ions, across a membrane.

Ion-exchange resin[5rezin]（离子交换树脂） A polymeric resin that contains fixed charged groups; used in chromatographic columns to separate ionic compounds.

Ion product of water (Kw)（水的离子积） The product of the concentrations of H+and OH- in pure water:

kw = [H+] X [OH- ] = 10-14 at 25 °C.

Isozymes[5ais[Uzaim]（同工酶） Multiple forms of an

Ionizing radiation[7reidi5eiFEn]（电离辐射） A type of

enzyme that catalyze the same reaction but differ from

radiation, such as x rays, that causes loss of electrons from

each other in their amino acid sequence, substrate affinity,

some organic molecules, thus making them more reactive.

Vm, and / or regulatory properties; also called isoenzymes.

Ionophore[ai5RnEfR:]（离子载体） A compound that

K

binds one or more metal ions and is capable of diffusing

Keratins[5kerEtin]( 角 蛋 白 ) Insoluble protective or

across a membrane, carrying the bound ion.

structural proteins consisting of parallel polypeptide chains

Iron-sulfur center（铁硫中心） A prosthetic group of

in α-helical or β conformations.

certain redox proteins involved in electron transfers; Fe2+

[7ki:tEU5dVenik] amino acids（生酮氨基酸）Amino acids

3+

or Fe

is bound to inorganic sulfur and to Cys groups in

with carbon skeletons that can serve as precursors of the

the protein.

ketone bodies.

Isoelectric focusing[7aisEUi5lektrik 5fEUkEsiN]（等电聚

Ketone bodies[5ki:tEUn 5bQdis]（酮体） Acetoacetate,

焦 ）

An

electrophoretic

method

for

separating

D-β-hydroxybutyrate, and acetone; water-soluble fuels

macromolccules on the basis of their isoelectric pH.

normally exported by the liver but overproduced during

Isoelectric pH (isoelectric point)( 等电点)

fasting or in untreated diabetes mellitus.

The pH at

which a solute has no net electric charge and thus does not

Ketose[5ki:tEUn]（酮糖） A simple monosaccharide in

move in an electric field,

which the carbonyl group is a ketone.

Isoenzymes[7aisEU5en7zaim]（同工酶） See isozymes.

Ketosis[ki5tEUsis]（酮尿症） A condition in which the

Isomerases[ai5sRmEreis] （ 异 构 酶 类 ） Enzymes that

concentration of ketone bodies in the blood, tissues, and

catalyze the transformation of compounds into their

urine is abnormally high.

positional isomers.

Kinases[5kineis] （ 激 酶 ） Enzymes that catalyze the

Isomers[5aisEUmE]（异构体）Any two molecules with the

phosphorylation of certain molecules by ATP.

same molecular formula, but a different arrangement of

Kinetics[kai5netiks]（动力学）The study of reaction rates.

molecular groups.

Krebs cycle[krebz 5saikl]（Krebs 循环）See citric acid

Isoprene[5aisEUpri:n] （ 异 戊 二 烯 ） The hydrocarbon

cycle.

2-methyl-1, 3-butadiene, a recurring structural unit of the terpenoid biomolecules.

Isoprenoid[7aisEU5prenRid]（类异戊二烯）Any of a large number of natural products synthesized by enzymatic polymerization of two or more isoprene units; also called terpenoids.

Isothermal[7aisEU5WE:mEl] （ 等 温 的 ） Occurring at constant temperature.

L Lagging strand[5lAgiN strAnd]（滞后链） The DNA strand that, during replication, must be synthesized in the direction opposite to that in which the replication fork moves.

Law of mass action（质量作用定律） The law stating that the rate of any given chemical reaction is proportional to the product of the activities (or concentrations) of the

Isotopes[5aisEUtEUp]（同位素） Stable or radioactive

reactants.

forms of an element that differ in atomic weight but are

Leader（ 前导序列） A short sequence near the amino

otherwise chemically identical to the naturally abundant form of the clement; used as tracers.

terminus of a protein or the 5' end of an RNA that has a specialized targeting or regulatory function.

Leading strand（领头链） The DNA strand that, during

Vmax and Km by extrapolation of [S] to infinity.

replication, is synthesized in the same direction in which

Linking number (连接数)The number of times one closed

the replication fork moves.

circular DNA strand is wound about another; the number

Leaky mutant（渗漏突变） A mutant gene that gives rise

of topological links holding the circles together.

to a product with a detectable level of biological activity,

Lipases[5lipeis] （ 脂 酶 ） Enzymes that catalyze the

Leaving group（离去基团） The departing or displaced

hydrolysis of triacylglycerols.

molecular group in a unimolecular elimination or a

Lipid[5lipid（脂） A small water-insoluble biomolecule

bimolecular substitution reaction.

generally containing fatty acids, st.erols, or isoprenoid

Lectin[5lektin] （ 凝 集 素 ） A protein that binds a

compounds.

carbohydrate, commonly an oligosaccharide, with very

Lipoate[5lipEUeit] (lipoic acid)（硫辛酸） A vitamin for

high

some microorganisms; an intermediate carrier of hydrogen

affinity

and

specificity,

mediating

cell-cell

interactions.

atoms and acyi groups hi a-keto acid dehydrogenases.

Lethal mutation5li:WEl mjU:5teiFEn]（ 致 死 突 变 ） A mutation that inactivates a biological function essential to the life of the cell or organism.

aggregate that serves to carry water-insoluble lipids in the blood. The protein component alone is an apolipoprotein.

Leucine zipper（亮氨酸拉链） A protein structural motif involved in protein-protein interactions in many eukaryotic regulatory proteins; consists of two interacting a helices in which Leu residues in every seventh position are a prominent, feature of the interacting surfaces.

Leukotrienes[liUkE5trains] （ 白 三 烯 ） A family of molecules derived from arachidonate; muscle contractants that constrict air passages in the lungs and are involved in asthma.

Levorotatory[li:vEU5rEUtE7tEri] isomer（左旋异构体） A stercoisomer that rotates the plane of plane-polarized light counterclockwise.

Ligand[5ligEnd] A small molecule that binds specifically to a larger one; for example, a hormone is the ligand for its specific protein receptor.

Ligases[li5geis] （ 连 接 酶 ） Enzymes that. catalyze condensation reactions in which two atoms are joined using the energy of ATP or another energy-rich compound.

Light-dependent reactions（光反应） The reactions of photosynthesis that require light and cannot, occur in the dark; also known as the light reactions.

Lineweaver-Burk equation

Lipoprotein[7lipE5prEUti:n]（脂蛋白） A lipid-protein

An algebraic transform of

the Michaells-Menten equation, allowing determination of

Liposome[5lipEUsEUm]（脂质体） A small, spherical vesicle composed of a phospholipid bilayer, which forms spontaneously when phospholipids are suspended in an aqueous buffer.

Low-energy phosphate compound( 低 能 化 合 物 ） A phosphorylated compound with a relatively small standard free energy of hydrolysis.

Lyases[5laiEs]（裂解裂合酶类）Enzymes that catalyze the removal of a group from a molecule to form a double bond, or the addition of a group to a double bond.

Lymphocytes [5limfEsait]（淋巴细胞） A subclass of leukocytes lymphocytes

involved

in

synthesize

the and

immune secrete

response.

B

antibodies;

T

lymphocytes either play a regulatory role in immunity or kill foreign and virus-infected cells.

Lysis[5laisis] （ 裂 解 ） Destruction of a cell's plasma membrane or of a bacterial cell wall, releasing the cellular contents and killing the cell.

Lysosome[5laisEUsEUm]（溶酶体）A membrane-bounded organelle in the cytoplasm of eukaryotic cells; it contains many hydrolytic enzymes and serves as a degrading and recycling center for unneeded components.

M

Michaelis constant (Km)（米氏常数） The substrate

Macromolecule[7mAkrEU5mRlikjU:l] （ 大 分 子 ）

A

concentration at which an enzyme-catalyzed reaction

molecule having a molecular weight in the range of a few

proceeds at one-Iialf its maximum velocity.

thousand to many millions.

Michaelis-Menten equation（米氏方程） The equation

Matrix[5meitriks]（基质） The aqueous contents of a cell

describing the hyperbolic dependence of the initial reaction

or organelle (the mitochondrion, for example) with

velocity, V, on substrate concentration, [S], in many

dissolved solutes.

enzyme-catalyzed reactions.

Meiosis[mai5EUsis]（减数分裂） A type of cell division in

Michaelis-Menten kinetics （米氏动力学）A kinetic

which diploid cells give rise to haploid cells destined to

pattern in which the initial rate of an enzyme-catalyzed

become gametes.

reaction exhibits a hyperbolic dependence on substrate

Membrane potential (Vm)（膜电位） The difference in

concentration.

electrical

Microbodies[5maikrEU7bRdi] （ 微 体 ）

potential

across

a

biological

membrane,

Cytoplasmic,

commonly measured by the insertion of a microelectrode.

membrane-bounded vesicles containing peroxide-forming

Typical membrane potentials vary from —25 mV (by

and peroxide-destroying enzymes; include lysosomes,

convention, the negative sign indicates that the inside is

peroxisomes, and glyoxysomes.

negative relative to the outside) to greater than —100 mV

Microfilaments[7maikrEJ5filEmEnt （ 微 丝 ）

across some plant vacuole membranes.

filaments composed of actin, found in the cytoplasm of

Membrane transport（膜转运） Movement of a polar

eukaryotic cells; serve in structure and movement.

solute across a membrane via a specific membrane protein

Microtubules[7maikrEU5tjU:bjU:l]（微管） Thin tubules

(a transporter).

assembled from two types of globular tubulin subunits;

Messenger RNA (mRNA)（信使RNA） A class of RNA

present, in cilia, flagella, centrosomes, and other contractile

molecules, each of which is complementary to one strand

or motile structures.

of DNA; carries the genetic message from the chromosome

Mismatch(碱基错配)

to the ribosomes,

cannot form normal Watson-Crick pairs.

Metabolism[me5tAbElizEm] (新陈代谢) The entire set of

Mismatch repair (错配修复) an enzymatic system for

enzyme-catalyzed transformations of organic molecules in

repairing base mismatches in DNA.

living cells; the sum of anabolism and catabolism.

Mitochondrion[7maitEJ5kRndriE] （ 线 粒 体 ）

Metabolite[mi5tAbElait] （ 代 谢 物 ）

A chemical

Membrane-bounded

intermediate

reactions

eukaryotes; contains the enzyme systems required for the

in

the

enzyme-catalyzed

of

metabolism.

Metalloprotein[mi7tAlE5prEUti:in] （ 金 属 蛋 白 ）

Thin

a base pair in a nucleic acid that

organelle

in

the

cytoplasm

of

citric acid cycle, fatty acid oxidation, electron transfer, and A

oxidative phosphorylation.

protein having a metal ion as its prosthetic group.

Mitosis[mi5tEUsis]（有丝分裂） The multistep process in

Metamerism[me5tAmErizEm]（分节） Division of the

eukaryotic cells that results in the replication of

body into segments; in insects, for example.

chromosomes and cell division,

Micelle[mi5sel]（微团） An aggregate of amphipathic

Mixed-function oxidases（混合功能氧化酶） Enzymes (a

molecules in water, with the nonpolar portions in the

monooxygenase, for example) that catalyze reactions in

interior and the polar portions at the exterior surface,

which two reductants, one of which is generally NADPH,

exposed to water.

the other the substrate, are oxidized. One oxygen atom is

incorporated into the product, the other is reduced to H2O.

Myofibril[7maiEJ5faibril]（肌原纤维）A unit of thick and

These enzymes often employ cylochrome P-450 to carry

thin filaments of muscle fibers.

electrons from NADPH to O2.

Myosin[5maiEsin]（肌球蛋白） A contractile protein; the

Mixed inhibition（混合抑制） The reversible inhibition

major component of the thick filaments of muscle and

pattern resulting when an inhibitor molecule can bind to

other actin-myosin systems.

either the free enzyme or to the enzyme-substrate complex

N

(not necessarily with the same affinity).

NAD,NADP

Modulator[5mRdjUleitE]（调节物） A Metabolite that,

dinucleotide,

when bound to the allosteric site of an enzyme, alters its

phosphate)(尼克酰胺腺嘌呤二核苷酸，尼克酰胺腺嘌呤

kinetic characteristics.

二 核 苷 酸 磷 酸 ) Nicotinamide-containing coenzyme:

Molar solution（摩尔溶液）One mole of solute dissolved

functioning as carriers of hydrogen atoms and electrons in

in water to give a total volume of 1000 mL.

some oxidation-reduction reactions.

Mole[mEUl] （摩尔）One gram molecular weight of a

Native conformation（天然构象） Ttie biologically active

compound. See Avogadro's number.

conformation of a macromolecule.

Monoclonal antibodies[7mRnE5klEJnEl 5Anti7bRdis]（单

Negative cooperativity[kEJ9RpErE5tivEti]（负协同性）A

克隆抗体） Antibodies produced by a cloned hybridoma

phenomenon of some inultisubunit enzymes or proteins in

cell, which therefore are identical and directed against the

which binding of a ligand or substrate to one subunit

same epitope of the antigen.

impairs binding to another subunit.

Monolayer（单分子层） A single layer of oriented lipid

Negative feedback（负反馈） Regulation of a biochemical

molecules.

pathway achieved when a reaction product. inhibits an

Monoprotic acid (单质子酸)An acid having only one

earlier step in the pathway.

dissociable proton-

Neuron[5njUErRn]（神经元） A cell of nervous tissue

Monosaccharide[7mRnEU5sAkEraid] （ 单 糖 ）

A

(nicotinamide[7nikE5tinEmaid]adenine nicotinamide

adenine

dinucleotide

specialized for transmission of a nerve impulse.

carbohydrate consisting of I single sugar unit.

Neurotransmitter[7njUErEtrAns5mitE]（神经递质）A low

mRNA: See messenger RNA.

molecular weight compound (usually containing nitrogen)

Mucopolysaccharide[7mjU:kEU7pRli5sAkE7raid] （ 粘 多

secreted from the terminal of a neuron and bound by a

糖） An older name for a glycosaminoglycan.

specific receptor in the next neuron; serves to transmit a

Multienzyme system（多酶系统） A group of related enzyme; participating in a given metabolic pathway.

Mutarotation[7mjU:tErEJ5teiFEn] （ 变 旋 现 象 ） The change in specific rotation o a pyranose or furanose sugar or glycoside accompanying tlie equilibration of its a- and j8- anomcric forms.

Mutases[5mjU:teis]（变位酶）: Enzymes that catalyze the transposition of functional groups.

Mutation An inheritable change in the nucleotide sequence of a chromosome.

nerve impulse.

Nicotinamide

adenine

dinucleotide,

nicotinamide

adenine dinucleotide phosphate: See NAD,NADP. Ninhydrin[nin5haidrin] reaction（茚三酮反应） A color reaction given by amino acida and peptides on heating with ninhydrin; widely used for their detection and estimation.

Nitrogen cycle（氮循环） The cycling of various forms of biologically available nitrogen through the plant, animal, and microbial worlds, and through the atmosphere and geosphere.

Nitrogen fixation（固氮作用）Conversion of atmospheric

nitrogen (N3) into a reduced, biologically available form

DNA and RNA.

by nitrogen-fixing organisms.

Nucleoid[5njU:kliRid]（拟核）In bacteria, the nuclear zone

Nitrogenase[5naitrEdVE7neis] complex（固氮复合物）A

that contains the chromosome but has no surrounding

system of enzymes capable of reducing atmospheric

membranc-

nitrogen to ammonia in the presence of ATP.

Nucleolus[njU:5kli:ElEs] （ 核 仁 ） A densely staining

Noncyclic electron flow （ 非 环 式 电 子 流 ）

The

+

structure in the nucleus of eukaryotic cells; involved in

light-induced tlow of electrons from water to NADP in

rRNA synthesis and ribosome formation.

oxygen-evolving

Nucleophile[5njU:kliEfail]（亲核剂） An electron-rich

photosynthesis;

it

involves

both

photosystems I and II.

group with a strong tendency to donate electrons tu an

Nonessential amino acids:（非必需氨基酸） Amino acids

electron-deficient nucleus (electrophilc); the entering

tliat can be made by humans and other vertebrates from

reactant in a bimolecular substitution reaction.

simpler precursors, and are thus not required in the diet.

Nucleoplasm[5njU:kliEplAzm]（核质）The portion of a

Nonheme iron proteins:（非血红素铁蛋白） Proteins,

cell's contents enclosed by the nuclear membrane; also

usually acting in oxidation-reduction reactions, containing

called the nuclear matrix.

iron but no porphyrin groups.

Nucleoside[5njU:kliEsaid] （ 核 苷 ）

Nopolar [5nRn5pEUlE] （ 非 极 性 的 ） Hydrophobic;

A compound

consisting of a purinc or pyrimidine base cuvalently linked

describing molecules or groups that are poorly soluble in

to a pentose.

water.

Nucleoside diphosphate kinase（核苷二磷酸激酶）An

Nonsense codon:（无义密码） A codon that docs not

enzyme that catalyzes the transfer of the terminal

specify an amino acid, but signals the termination of a

phosphate of a nucleoside 5'-triphosphate to a nucleoside

polypeptide chain.

5'-diphosphate.

Nonsense mutation: （无义突变） A mutation that results

Nucleoside diphosphate sugar （ 核 苷 二 磷 酸 糖 ） A

in the premature termination of a polypeptide chain.

coenzymelike carrier of a sugar molecule, functioning in

Nonsense suppressor（无义抑制） A mutation, usually in

the enzymatic synthesis of polysaccharides and sugar

the gene for a tRNA, that, causes an amino acid to be

derivatives.

inserted into a polypeptide in response to a termination

Nucleoside monophosphate kinase（核苷一磷酸激酶）

codon.

An enzyme that catalyzes the transfer of the termi(NMR)

nal phosphate of ATP to a nucleoside 5'-monophosphate.

spectroscopy[spek5trRskEpi]（核磁共振谱）A technique

Nucleosome[5njU:kliEsEUm]（核小体） Structural unit

that utilizes certain quantum mechanical properties of

for packaging chromatin; consists of a UNA strand

atomic nuclei to study the structure and dynamics of the

wound around a histone core.

molecules of which they are a part.

Nucleotide[5njU:kliEtaid] （ 核 苷 酸 ） A nucleoside

Nucleases[5njU:kli7eis]（核酸酶） Knzymes that hydrolyze

phosphorylated at one of its pentose hydroxyl groups.

the internucicotidc (phosphodiester) linkages of nucleic

Nucleus[5njU:kliEs] （ 细 胞 核 ）

acids.

membrane-bounded organellc that contains chromosomes.

Nuclear

magnetic

resonance

Nucleic acids[5njU:kliik 5Asid] （ 核 酸 ） Biologically occurring polynucleotides in which the nucleotide residues are linked in a specific sequence by phosphodiester bonds;

In cukaryotes, a

O Oligomer[5RligEUmE](寡聚体) A short polymer, usually

of amino acids, sugars, or nucleotides; the definition of

compartment containing solute at a higher concentration.

"short" is somewhat arbitrary, but usually less than 50

Osmotic[Rz5mRtik] pressure（渗透压）Pressure generated

subunits.

by the osmotic flow of water through a semipermeable

Oligomeric protein (寡聚蛋白) A multisubunit protein

membrane into an aqueous compartment containing solute

having two or more identical polypeptide chains.

at a higher concentration.

Oligonucleotide[9RligEJ5njU:kliEUtaid]（寡核苷酸）: A

Oxidases[5Rksideis]（氧化酶） Enzymes that catalyse

short polymer of nucleotides (usually less than 50).

oxidation reactions in which molecular oxygen serves as

Oligopeptide[9RligEJ5peptaid]（寡肽）A few amino acids

the electron acceptor, but neither of the oxygen atoms is

joined by peptide bonds.

Oligosaccharide[9RligEJ5sAkEraid] （ 寡 糖 ） Several monosaccharide groups joined by glycosidic bonds.

Oncogene[5RnkE7dVi:n]（致癌基因） A cancer-causing gene; any of several mutant genes that, cause cells to exhibit, rapid, uncontrolled proliferation. See also protooncogene.

Open reading frame （ 开 放 阅 读 框 ） A group of contiguous nonoverlapping nucleotide codons in a DNA or RNA molecule that do not include a termination codon.

Open system（开放系统） A system that exchanges matter and energy with its surroundings. See also system.

Operator[5RpEreitE](操纵基因) A region of DNA that interacts with a represser protein to control the expression of a gene or group of genes.

Operon[5RpE7rRn]（操纵子） A unit, of genetic expression consisting of one or more related genes and the operator and promoter sequences that regulate their transcription.

Optical[5RptikEl] activity （光学活性） The capacity of

incorporated into the product. Compare oxygenases.

Oxidation[（氧化作用） The loss of electrons from a compound.

Oxidation-reduction reaction: （ 氧 化 还 原 反 应 ） A reaction in which electrons are transferred from a donor to an acceptor molecule; also called a redox reaction.

Oxidative phosphorylation（氧化磷酸化）The enzymatic phosphorylation of ADP to ATP coupled to electron transfer from a substrate to molecular oxygen.

Oxidizing agent (oxidant)（氧化剂） The acceptor of electrons in an oxidation-reduction reaction.

Oxygen debt[5RksidVEn det]（氧债）The extra oxygen (above the normal resting level) consumed in the recovery period after strenuous physical exertion.

Oxygenases[5RksidVineis] （ 加 氧 酶 ） Enzymes that catalyze reactions in which oxygen atoms are directly incorporated into tile product, forming a hydroxyl or carboxyl

group.

In

reactions

catalyzed

by

a

monooxygenase, only one of the two 0 atoms is incorporated; the other is reduced to rLO; in reactions

a substance to rotate the plane of plane-polarized light.

catalyzed by a dioxygenase, both 0 atoms are incorporated

Optimum[5RptimEm] pH（最适pH）The characteristic pH

into the product. Compare oxidases.

at which an enzyme has maximal catalytic activity.

P

Organelles[7R:gE5nel]( 细 胞 器 ) Membrane-bounded

Palindrome[5pAlindrEUm]（回文结构）: A segment of

structures found in eukaryotic cells; contain enzymes and

duplex DNA in which the base sequences of the two

other components required for specialized cell functions.

strands exhibit twofold rotational symmetry about an axis.

Origin（起始位点） The nucleotide sequence or site in

Partition coefficient [pB:5tiFEnkEUi5fiFEnt]（分配系数）:

DNA where DNA replication is initiated.

A constant that expresses the ratio in which a given solute

Osmosis[Rz5mEUsis]（渗透作用） Bulk flow of water

will be partitioned or distributed between two given

through a semi-permeable membrane into another aqueous

immiscible liquids at equilibrium.

Pathogenic[9pAWE5dVenik]（病原性的） Disease-causing.

characteristics of an organism.

Pentose[5pentEUs] （ 戊 糖 ） A simple sugar with a

Phosphatases[5RsfEteis] （ 磷 酸 酯 酶 ） Enzymes that

backbone containing five carbon atoms.

hydrolyze a phosphate ester or anhydride, releasing

Pentosephosphate pathway（磷酸戊糖途径）: A pathway

inorganic phosphate, Pi.

that serves to interconvert hexoses and pentoses and is a

Phosphodiester linkage [5fRsfEdaiist[ 5liNkidV]（磷酸二

source

for

酯键） A chemical grouping that contains two alcohols

biosynthetic processes; present, in most organisms. Also

esterified to one molecule of phosphoric acid, winch thus

called the phosphogluconate pathway.

serves as a bridge between them.

Peptidases[5peptideis]（肽酶） Enzymes that hydrolyze

Phosphogluconate [5fRsfE5glU:kEU7neit] pathway（磷酸

peptide bonds.

己糖途径） An oxidative pathway beginning with glucose

Peptide（肽） Two or more ammo acids covaleiitly joined

6-phosphate and leading, via 6-phosphogluconate, to

by peptide bonds.

pentose phosphates and yielding NADPH. Also called the

Peptide bond （ 肽 键 ） A substituted amide linkage

pentose phosphate pathway.

between the a-amino group of one amino acid and the

Phospholipid[7fRsfEU5lipid]（磷脂） A lipid containing

a-carboxyl group of another, with the elimination of the

one or more phosphate groups.

elements of water,

Phosphorolysis[7fRsfE5Rlisis]（磷酸解） Cleavage of a

Peptide mapping （ 肽 指 纹 图 ） The characteristic

compound with phosphate as the attacking group;

two-dimensional pattern (on paper or gel) formed by the

analogous to hydrolysis.

separation of a mixture of peptides resulting from partial

Phosphorylases[5fRsfEri7leis]（磷酸化酶）Enzymes that

hydrolysis

catalyze phosphorolysis (defined above).

of

reducing

of

a

equivalents

protein;

also

and

pentoses

known

as

peptide

fingerprinting.

Phosphorylation[fR7sfRri5leiFEn] （ 磷 酸 化 作 用 ）

Peptidoglycan[9peptidEJ5glaikAn]（肽聚糖） A major

Formation of a phosphate derivative of a biomolecule,

component of bacterial cell walls; generally consists of

usually by enzymatic transfer of a phosphoryl group from

parallel

ATP.

heteropolysaccharides

cross-linked

by

short

peptides.

Phosphorylation potential (ΔGp)（磷酸化能力）: The

Peripheral proteins[pE5rifErEl 5prEUti:n]（外周蛋白）

actual free-energy change of ATP hydrolysis under the

Proteins that are loosely or reversibly bound to a

nonstandard conditions prevailing within a cell.

membrane by hydrogen bonds or electrostatic forces;

Photochemical [7fEUtEU5kemikEl]reaction center（光化

generally water-soluble once released from the membrane.

Permeases[5pV:mieis]（透过酶） See transporters.

学反应中心） The part of a photosynthetic complex where the energy of an absorbed photon causes charge separation,

Peroxisome[pE5rRksisEJm] （ 过 氧 化 物 酶 体 ）

initiating electron transfer.

Membrane-bounded

organelle

in

Photon[5fEUtRn]（光子）The ultimate unit (a quantum) of

cukaryotic

contains

peroxide-forming

cells;

the

cytoplasm

of and

peroxide-destroying enzymes.

Photophosphorylation[7fEUtEUfRsfEri5leiFEn]（光合磷酸

pH The negative logarithm of the hydrogen ion concentration of an aqueous solution.

化） The enzymatic formation of ATP from ADP coupled to

Phage: See bacteriophage.

Phenotype[5fi:nEtaip] （ 表 型 ）

light energy.

The

observable

the

light-dependent

photosynthetic cells.

transfer

of

electrons

in

Photoreduction[7fEUtEUri5dQkFEn] （ 光 还 原 ）

The

hydrogen-bonded arrangement of polypeptide chains in the

light-induced reduction of an electron acceptor in

extended 0 conformation.

phot.osynthetic cells.

Plectonemic[7plektEU5nemik](具绞旋线的) A structure

Photorespiration[7fEUtEU7respi5reiFEn] （ 光 呼 吸 ）

in a molecular polymer in which there is a net twisting of

Oxygen

strands about each other in some simple and regular way.

consumption

temperate-zone

plants,

occurring largely

in

due

illuminated to

oxidation

Polar[5pEUlE]（极性的) Hydrophilic, or "water-loving";

ofphosphoglycolate.

describing molecules or groups that are soluble in water.

Photosynthesis[7fEUtEU75inWEsis]（光合作用） The use of

Polarity[pEU5lAriti] （ 极 性 ） (1) In chemistry, the

light energy to produce carbohydrates from carbon dioxide

nonuniform distribution of electrons in a molecule; polar

and a reducing agent sucli as water.

molecules are usually soluble in water. (2) In molecular

Photosynthetic[7fEUtEUsin5Wetik]7 phosphorylation（光

biology, the distinction between the 5' and 3' ends of

合磷酸化） See photophosphorylation .

nucleic acids.

In

Poly(A) tail( 多 聚 腺 苷 酸 尾 ) A length of adenosine

photosynthetic cells, a functional set of light-absorbing

residues added to the 3' ends of many mRNAs in

pigments and its reaction center.

eukaryotes (and sometimes in bacteria).

Phototroph[5fEUtEU7trRf]（光能生物） An organism that.

Polycistronic[7pRlisis5trRnik] mRNA（多顺反子mRNA）

can use the energy of light to synthesize its own fuels from

A contiguous mRNA with more than two genes that can be

simple molecules such as carbon dioxide, oxygen, and

translated into proteins.

water; as distinct from a chemotroph.

Polyclonal antibodies [9pRli5klEJnEl 5Anti7bRdis](多克

pKa: The negative logarithm of an equilibrium constant.

隆抗体) A heterogeneous pool of antibodies produced in

Plasma membrane[5plAzmE 5membrein](质膜)

an animal by a number of different. B lymphocytes in

Photosystem[7fEUtEU75sistEm] （ 光 系 统 ）

The

exterior membrane surrounding the cytoplasm of a cell.

response to an antigen. Different antibodies in the pool

Plasma proteins（血浆蛋白） The proteins present in

recognize different parts of the antigen.

blood plasma.

Polylinker（多连接物）A short, often synthetic, fragment

Plasmalogen[plAz5mAlEdVin] （ 缩 醛 磷 脂 ） A

of DNA containing recognition sequences for several

phospholipid with an alkenyl ether substituent on the C-l of

restriction endomicleases.

glycerol.

Polymerase chain reaction (PCR)（聚合酶链式反应） A

Plasmid[5plAzmid] （ 质 粒 ）

An extrachromosomal,

repetitive

procedure

that

results

in

a

geometric

independently replicating, small circular DNA molecule;

amplification of a specific DNA sequence.

commonly employed in genetic engineering.

Polymorphic[9pRli5mR:fik]（多态性的） Describing a

Plastid[5plAstid]（质体） In plants, a self-replicating

protein for which amino acid sequence variants exist in a

organelle; may differentiate into a chloroplast.

population of organisms, but the variations do not destroy

Platelets[5pleitlit]（血小板） Small, enucleated cells that initiate blood clotting; they arise from cells called

the protein's function.

Polynucleotide[7pRli5njU:kljE7taid] （ 多 核 苷 酸 ）

A

megakaryocytes in the bone marrow. Also known as

covalently linked sequence of nucieotides in which the 3'

thrombocytes.

hydroxyl of the pentose of one nucleotide residue is joined

Pleated sheet[pli:tid Fi:t]（折叠片） The side-by-side,

by a phosphodiester bond to the 5' hydroxyl of the pentose of the next residue.

Polypeptide[7pRli5peptaid]（多肽）A long chain of amino

(macromolecule), including the sequence of monomeric

acids linked by pcptide bonds; the molecular weight, is

subunits and any interchain and intrachain covalent bonds.

generally less than 10,000.

Primary transcript[5praimEri 5trAnskript]（原初转录

Polyribosome[7pRli5raibEsEUm] （ 多 核 糖 体 ）

See

本） The immediate RNA product of transcription before

polysome.

any posttranscriptional processing reactions.

Polysaccharide[pRli5sAkEraid] （ 多 糖 ） A linear or

Primase[5praimeis]（引物酶）: An enzyme that catalyzes

branched polymer of monosaccharide units linked by

the formation of RNA oligonucleotides used as primers by

glycosidic bonds.

DNA polymerascs.

Polysome[5pRlisEUm](polyribosome): A complex of an

Primer[5praimE]（引物）A short oligomer (of sugars or

inRNA molecule and two or more ribosomes.

nucieotides, for example) to which an enzyme adds

P/O ratio（磷/氧比） The number of moles of ATP formed

additional monomeric subunits.

in oxidative phosphorylation per gO^ reduced (thus, per

Primer terminus[5praimE

pair of electrons passed to Oa). Experimental values used

end of the primer to which monomeric suhunits are added.

in this text are 2.5 for passage of electrons from NADH to

Primosome[5praimEsEUm]（引发体）An enzyme complex

(X, and 1.5 for passage of electrons from FADH to 0^,

that synthesizes the primers required for lagging strand

Some textbooks use the integral values of 3.0 and 2.0.

DNA synthesis.

Porphyria[pR5fiEriE]（卟啉症）Genetic condition resulting

Probe[prEUb]（探针）A labeled fragment of nucleic acid

from the lack of one or more enzymes required to

containing a nucleotide sequence complementary to a gene

synthesize porphyrins.

or genomic sequence that one wishes to detect in a

Porphyrin[5pR:fErin] （ 卟 啉 ） Complex nitrogenous

hybridization experiment,

compound containing four substituted pyrroles covalently

Processivity[prE5sesiviti] （ 持 续 合 成 能 力 ） For any

joined into a ring; often complexed with a central metal

enzyme tliat catalyzes the synthesis of a biological polymer,

atom.

the property of adding multiple subunits to the polymer

Positive cooperativity[5pRzEtiv kEJ7RpErE5tivEti]（正协

without dissociating from the substrate.

同性） A phenomenon of some multisubunit enzymes or

Prochiral[prEU5tFirEl] molecule（原手性化合物） A

proteins in which binding of a ligand or substrate to one

symmetric molecule that can react asymmetrically with an

subunit. facilitates binding to another subunit.

enzyme having an asymmetric active site, generating a

Posttranscriptional processing[9pEUsttrAns5kripFEnEl

chiral product.

5tE:minEs]（引物末端） The

prEU55sesiN]（转录后加工） The enzymatic processing

Projection formulas（透视式）A method for representing

of the primary RNA transcript, producing functional

molecules to show the configuration of groups around

mRNA, tRNA, and/or rRNA molecules.

chiral centers; also known as Fischer projection formulas.

Posttranslational

Prokaryote[prEU5kAriEUt]（原核生物） A bacterium; a

modification[9pEUsttrAns5leiFEnEl9mRdifi5keiFEn]

unicellular organism with a single chromosome, no nuclear

（翻译后修饰） Enzymatic processing of a polypeptide

envelope, and no membrane-bounded organelles.

chain after translation from its mRNA.

Promoter[prE5mEUtE]（启动子） A DNA sequence at.

Primary structure[5praimEri 5strQktFE]（一级结构） A

which RNA polymerase may bind, leading to initiation of

description of the covalent backbone of a polymer

transcription.

Proofreading[5prU:fri:diN]（校对） The correction of

errors in the synthesis of an information-containing

concentration; used in oxidative phosphorylation and

biopolymer by removing incorrect monomeric subunits

photophosphorylation to drive ATF synthesis.

after they have been covalent.ly added to the growing

Protoplasm[5prEUtEplAzEm]（原生质）A general term

polymer.

referring to the entire contents of a living cell.

Prostaglandins[7prRstE5glAndin]（前列腺素） A class of

Purine[5pjUEri:n]（嘌呤）A nitrogenous heterocyclic base

lipid-soluble, hormonelike regulatory molecules derived

found in nucleotides and nucleic acids; containing fused

from arachidonate and other polyunsaturated fatty acids.

pyrimidine and imidazole rings.

Prosthetic[prRs5Wetik] group（辅基） A metal ion or an

Puromycin[7pjUrEU5maisn]（嘌呤霉素）An antibiotic that

organic compound (other than an amino acid) that is

inhibits polypeptide synthesis by being incorporated into a

covalently bound to a protein and is essential to its activity.

growing

Proteasome[5prEUtiEsEUm]（蛋白酶体）Supramolecular

termination.

assembly of enzymatic complexes that. function in the

Pyranose[5paiLrEnEJs] （ 吡 喃 糖 ） A simple sugar

degradation of damaged or unneeded cellular proteins.

containing the six-membered pyran ring.

Protein（蛋白质）A macromolecule composed of one or

Pyridine[7pirE5dainE] nucleotide （ 嘧 啶 核 苷 酸 ） A

more polypeptide chains, each with a characteristic

nucleotide coenzyme containing the pyridine derivative

sequence of amino acids linked by peptide bonds,

nicotinamide; NAD or NADP.

Protein kinases（蛋白激酶） Enzymes that transfer the

Pyridoxal[7piri5dRksAl] phosphate（磷酸吡哆醛） A

terminal phosphoryl group of ATP or another nucleoside

coenzyme containing the vitamin pyridoxine (vitamin B(;) ;

tnphosphate to a Ser, Thr, Tyr, Asp, or His side chain in a

functions in reactions involving amino group transfer.

target protein, thereby regulating the activity or other

Pyrimidine[9paiL5rimidi:n] （ 嘧 啶 ） A nitrogenous

properties of that protein.

heterocyclic base found in nucleotides and nucleic acids.

Protein targeting（蛋白质分送）The process by which

Pyrimidine dimer（嘧啶二聚体） A covalently joined

newly synthesized proteins are sorted and transported to

dimer of two adjacent pyrimidine residues in DNA,

their proper locations in the cell.

induced by absorption of LIV light; most commonly

Proteoglycan[prEUtiE5glaikAn]（蛋白聚糖）A hybrid

derived from two adjacent thymines (a thymine dimer).

macromolecule consisting of a heteropolysaccharidc joined

Pyrophosphatase[pairEU5fRsfEteis]（焦磷酸 酶） See

to a polypeptide; the polysaccharide is the major

inorganic pyrophosphatase.

polypeptide

chain,

component.

causing

its

premature

Q

Proto-oncogene（原癌基因） A cellular gene, usually

Quantum[5kwRntEm]（量子） The ultimate unit

encoding a regulatory protein, that can be converted into an

of energy.

oncogene by mutation.

Quaternary [kwE5tE:nEri]structure（ 四级 结 构 ）The

Proton acceptor（质子受体） An anionic compound capable of accepting a proton from a proton donor; that is, a base.

three-dimensional structure of a multisubunit protein; particularly the manner in which the subunits fit together.

R

Proton donor（质子供体）The donor of a proton in an

R group: (1) Formally, an abbreviation denoting any alkyi

acid-base reaction; that is, an acid.

group. (2) Occasionally, used in a more general sense to

Proton-motive force（质子推动力）The electrochemical 1

potential inherent in a transmcmbrane gradient of H' '

denote virtually any organic substituent (the R groups of amino acids, for example).

Racemic[rE5si:mik] mixture (racemate[5reisimeit])（外

NAD"".

消旋化合物） An equimolar mixture of the u and

Redox reaction（氧还反应）: See oxidation-reduction

L

stereoisomers of an optically active compound.

reaction.

Radical[5rAdikEl]（自由基） An atom or group of atoms

Reducing agent (reductant)（还原剂）The electron donor

possessing an unpaired electron; also called a free radical.

in an oxidation-reduction reaction.

Radioactive isotope[5reidiEU5Aktiv 5aisEUtEUp]（放射性

Reducing end（还原端）The end of a polysaccharide

同位素）An isotopic form of an element with an unstable

having a terminal sugar with a free anomeric carbon; the

nucleus that stabilizes itself by emitting ionizing radiation.

terminal residue can act aa a reducing sugar.

Radioimmunoassay[5reidiEU7imjUnEU5Asei]（放射免疫 实验）A sensitive and quantitative method for detecting trace amounts of a biomolecule, based on its capacity to displace a radioactive form of the molecule from combination with its specific antibody.

Rate constant（速度常数）The proportionality constant that relates the velocity of a chemical reaction to the concentration(s) of the reactant(s).

Rate-limiting step（限速步骤） (1) Generally, the step in an enzymatic reaction with the greatest activation energy or the transition state of highest free energy. (2) The slowest step in a metabolic pathway.

Reaction intermediate（反应中间产物） Any chemical species in a reaction pathway that has a finite chemical lifetime.

Reading

frame （ 阅 读 框 ） A

contiguous

and

nonoverlapping set of three-nucleotide codons in DNA or RNA. Recombinant[ri5kRmbinEnt] DNA（重组DNA） DNA formed by the joining of genes into new combinations.

Recombination(重组)Any enzymatic process by which the linear arrangement of nucleic acid sequences in a chromosome is altered by cleavage and rejoining.

Recombinational DNA repair （ 重 组 DNA 修 复 ） : recombinational processes that are directed at the repair of DNA strand breaks or cross-links, especially at inactivated replication forks.

Redox pair （ 氧 还 对 ） An electron donor and its corresponding oxidized form; for example, NADH and

Reducing equivalent A general or neutral term for an electron or an electron equivalent in the form of a hydrogen atom or a hydride ion.

Reducing sugar（还原糖）A sugar in which the carbonyl Canomeric) carbon is not involved in a glycosidic bond and can therefore undergo oxidation.

Reduction[ri5dQkFFEn]（还原）Tlie gain of electrons by a compound or ion.

Regulatory[5regjUlEtEri] enzyme（调节酶）An enzyme having a regulatory function through its capacity to undergo a change in catalytic activity by allosteric mechanisms or by covalent modification.

Regulatory gene（调节基因） A gene that gives rise to a product involved in the regulation of the expression of another gene; for example, a gene coding for a represser protein.

Regulatory sequence （ 调 节 序 列 ） A DNA sequence involved in regulating the expression of a gene; for example, a promoter or operator.

Regulon[5regjUlRn] （ 调 节 子 ） A group of genes or operons that are coordinately regulated even though some, or all, may be spatially distant within the chromosome or genome.

Relaxed DNA（松弛DNA）Any DNA that exists in its most stable and unstrained structure, typically B form under most cellular conditions.

Release factors（终止释放因子）See termination factors.

Releasing factors: Hypothalamic hormones lhat stimulate release of other hormones by the pituitary gland, Renaturation[5ri:7neitFE5reiFEn]（复性） Refolding of an

unfolded (denatured) globular protein so as to restore

cells.

native structure and protein function.

Restriction endonucleases[ris5trikFEn 7endE5njU:kli7eis]

Replication[7repli5keiFEn]（复制）Synthesis of daughter

（限制性内切酶） Site-specific endodeoxyribonucleases

nucleic acid molecules identical to the parental nucleic

causing cleavage of both strands of DNA at points within

acids.

or near the specific site recognized by the enzyme;

Replication fork （ 复 制 叉 ） The Y-shaped structure

important tools in genetic engineering.

generally found at the point where DNA is being

Restriction fragment[ris5trikFEn 5frAgmEnt]（限制性片

synthesized.

段）A segment of double-stranded UNA produced by the

Replicative form（复制形式） Any of the full-length

action of a restriction endonuclease on a larger DNA.

structural forms of a viral chromosome that serve as

Restriction fragment length polymorphisms (RFLPs)

distinct replication intermediates.

（限制片段长度多态性）: Variations, among individuals

Replisome[5replisEUm] （ 复 制 体 ） The multiprotein

in a population, in the length of certain restriction

complex that promotes DNA synthesis at the replication

fragments within which certain genomic sequences occur.

fork.

These variations result from rare sequence changes that

Repressible[ri5pesEbl] enzyme（阻遏酶） In bacteria, an

create or destroy restriction sites in the genome.

enzyme whose synthesis is inhibited when its reaction

Retrovirus[7retrEU5vaiErEs]（反转录病毒） An RNA

product is readily available to the cell.

virus containing a reverse transcriptase.

Repression[ri5preFEn] （ 阻 遏 ）

A decrease in the

Reverse transcriptase[ri5vE:s trAns5kripteis]（反转录

expression of a gene in response to a change in the activity

酶）: An RNA-directed DNA polymerase in retroviruses;

of a regulatory protein.

capable of making DNA complementary to an RNA.

Represser[ri5presE]（阻遏蛋白）The protein that binds to

Ribonuclease[7raibEU5njU:klieis] （ 核 糖 核 酸 酶 ） A

the regulatory sequence or operator for a gene, blocking its

nuclease

transcription.

internucleotide linkages of RNA.

Residue[5rezidjU:]（残基） A single unit within a polymer;

Ribonucleic acid[7raibEU5njU:kliik 5Asid]（核糖核酸）

for example, an amino acid within a polypeptide chain. The

See RNA.

term reflects the fact that sugars, nucleotides, and amino

Ribonucleotide[7raibEU5nU:kliE7taid]（核糖核苷酸）A

acids lose a few atoms (generallytne elements of water) when incorporated in their respective polymers.

Respiration[7respi5reiFEn]（呼吸）Any metabolic process that leads to the uptake of oxygen and tlie release of COg. Respiration-linked phosphorylation（呼吸链磷酸化） ATP formation from ADP and Pp driven by electron flow through a series of membrane-bound carriers, with a proton gradient as the direct source of energy driving rotational catalysis by ATPsynthase, Respiratory chain （呼吸链） The electron transfer chain; a sequence of electron-carrying proteins that transfer electrons from substrates to molecular oxygen in aerobic

that.

catalyzes

the

hydrolysis

of

certain

nucleotide containing D-ribose as its pentose component.

Ribosomal RNA （rRNA）（核糖体RNA） A class of RNA molecules serving as components of ribosomes.

Ribosome[5raibEsEUm] （ 核 糖 体 ） A supramolecular complex of rRNAs and proteins, approximately 18 to 22 imi in diameter; the site of protein synthesis.

Ribozymes[5raibEzaim] ( 核 酶 ) Ribonucleic acid molecules with catalytic activities; RNA enzymes.

Rieske iron-sulfur protein （Rieske铁硫蛋白） A type of iron-sulfur protein in which two of the ligands to the central iron ion are His side chains. These proteins act in

many electron-transfer sequences, including oxidative

Secondary metabolism[5sekEndEri me5tAbElizEm]（次

phosphorylation and photophosphorylation.

生代谢）Pathways that lead to specialized products not

RNA (ribonucleic acid): A polyribunucleotide of a

found in every living cell.

specific

Secondary structure[5sekEndEri 5strQktFE]（二级结构）

sequence

linked

by

successive

3',

5'-phosphodiester bonds.

The residue-by-residue conformation of the backbone of a

RNA polymerase （ RNA 聚 合 酶 ） An enzyme that

polymer.

catalyzes the formation of RNA from ribonucleoside

Sedimentation coefficient[7sedimen5teiFEn kEUi5fiFEnt]

S'-triphosphates, using a strand of DNA or RNA as a template.

（沉降系数） A physical constant, specifying the rate of sedimentation of a particle in a centrifugal field under

RNA splicing[5splaisiN]（RNA拼接）Removal of introns

specified conditions.

and joining of exons in a primary transcript.

Selectins[5si5lektin] （ 选 择 蛋 白 ） A large family of

rRNA: See ribosomal RNA.

membrane proteins, lectins [5lektin](凝集素) that bind S

oligosaccharides on other cells tightly and specifically, and

S-adenosylmethionine[E9denEsilmE5WaiEni:n]

serve to carry signals across the plasma membrane.

(adoMet) （ S- 腺 苷 蛋 氨 酸 或 活 化 蛋 氨 酸 ） An

SELEX; A method for rapid experimental identification of

enzymatic cofactor involved in methyl group transfers.

nucleic acid sequences (usually RNA) that have particular

Salvage[5sAlvidV] pathway（补救途径）Synthesis of a

catalytic or ligand-binding properties.

biomolecule, such as a nucleotide, from intermediates in

Serpentine receptors[5sE:pEntain ri5septEs]（蜿蜒受

the degradative pathway for the biomolecule; a recycling

体） A large family of membrane receptor proteins with

pathway, as distinct from a de novo pathway.

seven trans-membrane helical segments. These receptors

Saponification[sEpRnifi5keiFEn]（皂化作用）Alkaline

often associate with G proteins to transduce an

hydrolysis of triacylglycerols to yield fatty acids as soaps.

extracellular signal into a change in cellular metabolism.

Sarcomere[5sB:kEmiE]（肌节）A functional and structural

Shine-Dalgarno sequence（SD序列） A sequence in an

unit of the muscle contractile system.

mRNA required for binding prokaiyotic ribosomes.

Satellite[5sAt[lait] DNA（卫星DNA） Highly repeated, nontranslated

segments

of

DNA

in

eukaryotic

chromosomes; most often associated with the centromeric region. Its function is not clear.

Saturated[5sAtFEreitid] fatty acid (饱合脂肪酸) A fatty acid containing a fully saturated alkyl chain.

Second law of thermodynamics[5WE:mEUdai5nAmiks] （热力学第二定律）The law stating that in any chemical or physical process, the entropy[5entrEpi]( 熵 ) of the universe tends to increase.

SH2 domain[dEU5mein] A protein domain that binds tightly to a phosphotyrosine residue in certain proteins such as the receptor tyrosine kinases, initiating the formation of a multiprotein complex that acts in a signaling pathway.

Shuttle vector[5FQtl 5vektE]（穿梭载体） A recombinant DNA vector that can be replicated in two or more different host species. See also vector.

Sickle-cell anemia[E5ni:miE]（镰刀型贫血病）A human disease characterized by defective hemoglobin molecules; caused by a homozygous allele coding for the β chain of

Second messenger[5sekEnd5mesindVE]（第二信使）An

hemoglobin.

effector molecule synthesized within a cell in response to

Sickle-cell trait[treit]（镰刀性状） A human condition

an external signal (first messenger) such as a hormone.

recognized by the sickling of erythrocytes when exposed to

except the germ-line cells（生殖细胞）.

low oxygen tension; occurs in individuals heterozygous for

SOS response（应急反应） In bacteria, a coordinated

the allele responsible for sickle-cell anemia.

induction of a variety of genes as a response to high levels

Signal sequence[5signl 5si:kwEns] （ 信 号 序 列 ） An

of DNA damage.

amino acid sequence, often at the amino terminus, that

Southern blot[5sQTEn blRt]（Southern印迹法）A DNA

signals the cellular fate or destination of a newly

hybridization procedure in which one or more specific

synthesized protein.

DNA fragments are detected in a larger population by

Signal transduction[5signl trAns5dQkFEn]（信号传导）

means of hybridization to a complementary, labeled

The process by which an extracellular signal (chemical,

nucleic acid probe.

mechanical, or electrical) is amplified and converted to a

Specific

cellular response.

kE5tAlisis]（狭义酸碱催化） Acid or base catalysis

Silent mutation[5sailEnt mjU:5teiFEn]（沉默突变）A

involving the constituents of water (hydroxide or

mutation in a gene that causes no detectable change in the

hydronium ions).

biological characteristics of the gene product.

Specific activity[spi5sifik Ak5tiviti]（比活力）The number

Simple diffusion[5simpl di5fjU:VEn]（简单扩散） The

of micromoles (µmol) of a substrate transformed by an

movement of solute molecules across a membrane to a

enzyme preparation per minute per milligram of protein at

region of lower concentration, unassisted by a protein

25 °C; a measure of enzyme purity.

transporter.

Specific heat[spi5sifik hi:t]（比热）The amount of energy

Simple protein[5simpl 5prEUti:n]（简单蛋白） A protein

(in joules[dVjU:l]焦耳 or calories) needed to raise the

yielding only amino acids on hydrolysis,

acid-base

catalysis[spi5sifik

5Asid-beis

temperature of 1 g of a pure substance by 1 ºC.

Site-directed mutagenesis[7mjUtE5dVenisis]（定点突变） A set of methods used to create specific alterations in the sequence of a gene.

Specific rotation[spi5sifik rEU5teiFEn]（比旋光度）The rotation, in degrees, of the plane of plane-polarized light （平面偏振光）(D-line of sodium[5sEUdjEm]，钠的D线)

Site-specific recombination[5ri:kRmbi5neiFEn] （定点重

by an optically active compound at 5 °C, with a specified

组） A type of genetic recombination that occurs only at

concentration and light path.

specific sequences.

Specificity[7spesi5fisiti]（特异性，专一性） The ability

Size-exclusion

chromatography

[saiz-iks5klU:VEn

of an enzyme or receptor o discriminate among competing

7krEUmE5tRgrEfi]（分子排阻层析） A procedure for the

substrates or ligands,

separation of a mixture of molecules on the basis of size,

Sphingolipid[9sfiNg[J5lipid] （ 神 经 鞘 磷 脂 ）

based on the capacity of porous polymers to exclude solutes above a certain size. Also called gel filtration(凝胶

An

amphipathic lipid with a sphingosine（鞘氨醇） backbone to which are attached a long-chain fatty acid and a polar

过滤).

alcohol.

Small nuclear RNA (snRNA)（小核RNA）Any of several

Spliceosome[slaisi5EUsEUm]（拼接体） A complex of

small RNA molecules in the nucleus; most have a role in

RNAs and proteins involved in the splicing of mRNAs in

the splicing reactions that remove introns from mRNA,

eukaryotic cells.

tRNA, and rRNA molecules.

Splicing[5spaisiN](拼接) See gene splicing; RNA splicing.

Somatic cells [sEU5mAtik sels](体细胞) All body cells

Standard free-energy change (ΔG΄°)（标准自由能变化）

The free-energy change for a reaction occurring under a set

Substrate-level phosphorylation（底物水平磷酸化）

of standard conditions: temperature, 298 K; pressure, 1 atm

Phoyphorylation of ADP or some other nucleoside

concentration. ΔG΄°

5'-diphosphate coupled to the dehydrogenation of an

or 101.3 kPa; and all solutes at 1

M

denotes the standard free-energy change at pH 7.0.

organic substrate; independent of the electron-transfer

Standard reduction potential (Έ’°): The electromotive

chain（电子传递链）.

force exhibited at an electrode by 1

M

concentrations of a

reducing agent and its oxidized form at 25 °C and pH 7.0; a measure of the relative tendency of the reducing agent to lose electrons.

Steady state[5stedi steit]（稳态）A nonequilibrium state of a system through which matter is flowing and in which all components remain at, a constant concentration.

Stem cells（干细胞）The common, self-regenerating cells in bone marrow[5mArEu7]( 骨 髓 ) that give rise to differentiated blood cells such as erythrocytes and lymphocytes.

Stereoisomers[stiEriEU5ais[m[] （ 立 体 异 构 体 ） Compounds that have the same composition and the same order of atomic connections, but different molecular arrangements.

Sterols[5ster[Ul]（固醇类）A class of lipids containing the steroid nucleus. sticky ends（粘性末端） Two DNA ends in the same DNA molecule, or in different molecules, with short overhanging single-stranded segments that are complementary to one another, facilitating ligation of the ends; also known as cohesive[kEU5hi:siv] ends.

Stop codons（终止密码）See termination codons.

Stroma[5str[um[]（叶绿体基质）The space and aqueous solution enclosed within the inner membrane of a chloroplast, not including the contents within the thylakoid membranes.

Structural gene（结构基因）A gene coding for a protein or RNA molecule; as distinct, from a regulatory gene.

Substitution mutation（碱基替换突变） A mutation caused by the replacement of one base by another.

Substrate[5sQbstreit]（底物） The specific compound acted upon by an enzyme.

Suicide inhibitor[5sjuisaid in5hibit[]（自杀性抑制剂） A relatively inert molecule that is transformed by an enzyme, at its active site, into a reactive substance that irreversibly inactivates the enzyme.

Supercoil[5sju:p[7kRil] （ 超 螺 旋 ） The twisting of a helical (coiled) molecule on itself; a coiled coil.

Supercoiled DNA（超螺旋DNA）DNA that twists upon itself because it is under- or overwound (and thereby strained) relative to B-form DNA. Superhelical density[9sju:p[5helikEl 5densiti]（超螺旋密 度）: In a helical molecule such as DNA, the number of supercoils (superhelical turns) relative to the number of coils (turns) in the relaxed molecule.

Suppressor mutation[s[5pres[ mjU:teiFEn]（抑制基因 突 变 ） A mutation that totally or partially restores a function lost by a primary mutation; located at a site different, from the site of the primary mutation, Svedberg[5sfed7b[:g (S): (沉降系数)A unit of measure of the rate at which a particle sediments in a centrifugal field.

Symbionts[5simbaiRnt] （ 共 生 体 ）

Two or more

organisms that are mutually interdependent; usually living in physical association.

Symport[5simpR:t]（共转运）Cotransport of solutes across a membrane in the same direction.

Synthases[5sinWeis] （ 合 酶 ） Enzymes that catalyze condensation reactions in which no nucleoside triphosphate is required as an energy source.

Synthetase[5sinWeteis]（合成酶）Enzymes that catalyze condensation reactions using ATP or another nucleoside triphosphate as an energy source.

System（系统）An isolated collection of matter; all other matter in the universe apart from the system is called the

surroundings（环境）.

磷酸硫胺素）The active coenzyme form of vitamin B1; involved in aldehyde transfer reactions.

T Telomere[5tel[mi[] （ 端 粒 ） Specialized nucleic acid

Thioester[7WaiEU5est[]（硫酯） An ester of a carboxylic

structure found at the ends of linear eukaryotic

acid with a thiol or mercaptan.

chromosomes.

3' end: （3'端）The end of a nucleic acid that lacks a

Template[5templit]（模板） A macromolecular mold or

nucleotide bound at the 3' position of the terminal residue.

pattern

Thromboxanes[WrRm5bRksein]（凝血恶烷类） A class of

for

the

synthesis

of

an

informational

macromolecule.

molecules derived from arachidonate[[5rAkidRneit]（花生

template strand（模板链）A strand of nucleic acid used by

四烯酸） and involved in platelet aggregation during blood

a polymerase as a template to synthesize a complementary

clotting.

strand.

Thylakoid[5WailE7kRid] （ 类 囊 体 ）

terminal transferase[5t[:minl 5trAnsfE7reis]（末端转移 酶） An enzyme that catalyzes the addition of nucleotide residues of a single kind to the 3' end of DNA chains.

protein synthesis, signal the termination of a polypeptide chain. Also known as stop codons.

cytosol required in releasing a completed polypeptide chain from a ribosome; also known as release factors.

appears at the end of a transcriptional unit and signals the end of transcription.

Terpenes[5t[:pi:n] （ 萜 类 ） Organic hydrocarbons or from

recurring

isoprene units. They produce some of the scents and tastes of plant products.

Tertiary[5t[:FEri] structure （ 三 级 结 构 ）

The

three-dimensional conformation of a polymer in its native folded state.

Tetrahydrobiopterin[7tetr[7haidr[5bai[Upterin]（四氢 生物喋呤）The reduced coenzyme form of biopterin（生 物喋呤）.

by

the

pigment-bearing internal membranes of chloroplasts.

See pyrimidine dimer. tissue culture （组织培养） Method by which cells media. titration curve(滴定曲线) A plot of the pH versus the

Tocopherols[t[U5kRf[r[Ul]（生育酚）Forms of vitamin E. topoisomerases（拓扑异构酶） Enzymes that introduce positive or negative supercoils in closed, circular duplex DNA. Topoisomers[tEUpEU5aisEUmE]（拓扑异构体）Different forms of a covalently closed, circular DNA molecule that differ only in their linking number.

Topology[t[5pRl[dVi] （ 拓 扑 学 ） The study of the properties of an object that do not change under continuous deformations such as twisting or bending.

Toxins[5tRksin]（毒素蛋白）Proteins produced by some organisms and toxic to certain other species. trace element（痕量元素） A chemical element required

Tetrahydrofolate[7tetr[7haidr[5fEUleit]（四氢叶酸） The reduced,

formed

equivalents of base added during titration of an acid.

termination sequence（终止序列） A DNA sequence that

constructed

disk,

derived from multicellular organisms are grown in liquid

termination factors（终止因子） Protein factors of the

derivatives

or

thymine dimmer[5Waimi:n 5daim[]（胸腺嘧啶二聚体）

termination codons（终止密码）UAA, UAG, and UGA; in

hydrocarbon

cisterna[sis5tE:nE]( 池 ),

Closed

active

coenzyme

form

of

the

vitamin

folate[ 5fEUleit](叶酸). thiamine pyrophosphate[5Wai[mi:n 7pair[U5fRsfeit]（焦

by an organism in only trace amounts.

Transaminases[trAn5sAmineis] （ 转 氨 酶 ） See aminotransferases（氨基转移酶）.

Transamination[trAn7sAmi5neiF[n] （ 转 氨 作 用 ）

Enzymatic transfer of an amino group from an α-amino

Translocase[trAns5lEUkeis]（转运酶、移位酶） (1) An

acid to an α-keto acid.

enzyme that catalyzes membrane transport. (2) An enzyme

Transcription[trAns5kripF[n]（转录） The enzymatic

that causes a movement, such as the movement of a

process whereby the genetic information contained in one

ribosome along an mRNA.

strand of DNA is used to specify a complementary

Transpiration[7trAnspi5reiF[n]（蒸腾作用）Passage of

sequence of bases in an mRNA chain.

water from the roots of a plant to the atmosphere via the

transcriptional control（转录控制）The regulation of a

vascular[5vAskjulE] system（脉管系统） and the stomata

protein's synthesis by regulation of the formation of its

（气孔） of the leaves.

mRNA.

Transporters[trAn5spR:t[]（转运体） Proteins that span

Transduction[trAns5dQkF[n][（能量）转换、（信息）

a membrane and transport specific nutrients, metabolites,

传 导 ] (1) Generally, the conversion of energy or

ions, or proteins across the membrane; sometimes called

information from one form to another. (2) The transfer of

permeases (透过酶)

genetic information from one cell to another by means of a viral vector.

a gene or set of genes from one site in the genome to

transfer RNA (tRNA)（转移RNA）A class of RNA molecules (M,. 25,000 to 30,000), each of which combines covalently with a specific amino acid as the first step in protein synthesis.

Transformation[7trAnsf[5meiFEn](转化) Introduction of an exogenous DNA into a cell, causing the cell to acquire a new phenotype.

Transgenic[trAnsdVinik]（转基因的） Describing an organism

that

Transposition[7trAnsp[5ziF[n]（转座） The movement of

has

genes

from

another

organism

incorporated within its genome as a result of recombinant

another.

Transposon[trAns5pEUsRn] (transposable element)（转 座子）A segment of DNA that can move from one position in the genome to another.

Triacylglycerol[trai7Asil5^lis[r[ul]（三酰甘油）An ester of glycerol with three molecules of fatty acid; also called a triglyceride[trai5glisEraid]( 三 酰 甘 油 酯 ) or neutral fat （中性酯）.

Tricarboxylic[trai7kB:bCk5silik] acid cycle（三羧酸循

DNA procedures.

环） See citric acid cycle,

transition state （ 过 渡 态 ） An activated form of a

Triose[5trai[Us]（丙糖）A simple sugar with a backbone

molecule in which the molecule has undergone a partial

containing three carbon atoms.

chemical reaction; the highest point on the reaction

tRNA: See transfer RNA.

coordinate(反应进程图).

tropic hormone (tropin)（促激素） A peptide hormone

Translation[trAns5leiFEn]（翻译）The process in which

that stimulates a specific target gland to secrete its

the genetic information present in an mRNA molecule

hormone; for example, thyrotropin[9WairEU5trEJpin](促甲

specifies the sequence of amino acids during protein

状腺素) produced by the pituitary stimulates secretion of

synthesis.

thyroxine[Wai5rRksi:n]（甲状腺素. 甲状腺氨酸） by the

translational control（翻译控制） The regulation of a

thyroid（甲状腺）.

protein's synthesis by regulation of the rate of its

turnover number（周转数） The number of times an

translation on the ribosome.

enzyme molecule transforms a substrate molecule per unit

translational repressor[ri5pres[r] （ 翻 译 阻 遏 物 ） A

time, under conditions giving maximal activity at substrate

represser that binds to an mRNA, blocking translation.

concentrations that are saturating.

Vectorial[vektErEl] metabolism （ 方 向 性 代 谢 ）

U

Metabolic transformations in which the location (not the

Ubiquitin [jUbi5kwi:tin] （ 泛 蛋 白 ） A small, highly

chemical composition) of a substrate changes relative to a

conserved protein that targets an intracellular protein for

cellular

degradation by proteasomes. Several ubiquitin molecules

Transporters catalyze vectorial reactions, as do the proton

are covalently attached in tandem to a Lys residue in the

pumps of oxidative and photophosphorylation.

target protein by a specific ubiquitinating enzyme.

Viral[5vair[l] vector（病毒载体）A viral DNA altered so

ultraviolet (UV) radiation[5Qltr[5vai[lit 7reidi5eiFEn]（紫

that it can act as a vector for recombinant DNA.

外辐射） Electromagnetic radiation in the region of 200 to

Virion[5vai[riRn]（病毒粒）A virus particle.

400 nm.

Virus[5vai[r[s] （ 病 毒 ） A self-replicating, infectious,

Uncompetitive[QnkEm5petitiv] inhibition（反竞争性抑

nucleic acid-protein complex that requires an intact host

制） The reversible inhibition pattern resulting when an

cell for its replication; its genome is either DNA or RNA.

inhibitor molecule can bind to the enzyme-substrate

Vitamin[5vait[min]（维生素） An organic substance

complex but not to the free enzyme.

required in small quantities in the diet of some species;

Uncoupling[5Qn5kQpliN] agent（解偶联剂） A substance

generally functions as a component of a coenzyme.

membrane

dividing

that uncouples phosphorylation of ADP from electron transfer; for example, 2,4-dinitrophenol[7dai7naitrEU5fi:nRl] （2，4-二硝基苯酚）.

two

compartments.

W wild type（野生型） The normal (unmutated) phenotype.

Wobble[5wCbl]（摆动、变偶） The relatively loose base

Uniport[5jUnipR:t]（单向转运）A transport system that carries only one solute, as distinct from cotransport,

pairing between the base at the 3' end of a codon and the complementary base at the 5' end of the anticodon.

Unsaturated[5Qn5sAtF[reitid] fatty acid（不饱合脂肪

X

酸） A fatty acid.containing one or more double bonds.

x-ray crystallography[krist[5lRgr[fi]（X-射线晶体学）

Urea[5jU[ri[] cycle（尿素循环） A metabolic pathway in

The analysis of x-ray diffraction patterns of a crystalline

vertebrates, for the synthesis of urea from amino groups

compound,

and carbon dioxide; occurs in the liver.

three-dimensional structure.

Ureotelic[7jUEri[U5telik]（排尿素的）Excreting excess

used

to

determine

the

molecule's

Z

nitrogen in the form of urea.

Zink[ziNk] finger ( 锌 指 ) A specialized protein

Uricotelic[7jU[rik[5telik]（排尿酸的） Excreting excess

motif[m[U5ti:f](基序) involved in DNA recognition by

nitrogen in the form of urate (uric acid).

some DNA-binding proteins, characterized by a single

V Vmax （ 最大反应速度 ） The maximum velocity of an enzymatic reaction when the binding site is saturated with substrate, Vector（载体） A DNA molecule known to replicate autonomously in a host cell, to which a segment of DNA may be spliced to allow its replication; for example, a plasmid or an artificial chromosome.

atom of zinc coordinated[kEU55R:dinit](配位) to four Lys residues or to two His and two Lys residues.

Zwitterion[5tsvit[rai[n]（兼性离子）A dipolar ion, with spatially separated positive and negative charges.

Zymogen[5zaim[dVen]（酶原） An inactive precursor of an enzyme; for example, pepsinogen [pep5sin[dV[n](胃 蛋白酶原), the precursor of pepsin[5pepsin]（胃蛋白酶）。