双语教学中的生物化学词汇

第一篇：双语教学中的生物化学词汇

双语生物化学词汇

Glossary of Biochemistry Bilingually

A Absolute configuration（绝对构型）The configuration of four different substituent groups around an asymmetric carbon atom, in relation to u-and i.-glyceraldehyde.Absorption（吸收）: transport of the products of digestion from the intestinal tract into the blood.Acceptor control（受体控制）: The regulation of the rate of respiration by the availability of ADP as phosphate group acceptor.Accessory pigments（辅助色素）: Visible light-absorbing pigments(carotenoids, xanthophyll, and phycobilins藻胆素)in plants and photosynthetic bacteria that complement chlorophylls in trapping energy from sunlight.Acidosis（酸中毒）: A metabolic condition in which the capacity of the body to buffer is diminished;usually accompanied by decreased blood pH.Actin（肌动蛋白）: A protein making up the thin filaments（细丝）of muscle;also an important component of the cytoskeleton of many eukaryotic cells.Activation energy(ΔG*)（活化能）: The amount of energy(in joules)required to convert all the molecules in 1 mole of a reacting substance from the ground state to the transition state.Activator:（活化物、激活剂）(1)A DNA-binding protein that positively regulates the expression of one or more genes;that is, transcription rates increase when an activator is bound to the DNA.(2)A positive modulator of an allosteric enzyme.Active site:（活性部位）The region of an enzyme surface that binds the substrate molecule and catalytically transforms it;also known as the catalytic site.Active transport:（主动运输）Energy-requiring transport of a solute across a membrane in the direction of increasing concentration.Activity:（活度）The true thermodynamic activity or potential of a substance, as distinct from its molar concentration.Activity coefficient:（活度系数）The factor by which the numerical value of the concentration of a solute must be multiplied to give its true thermodynamic activity.Adenosine 3',5'-cyclic monophosphate: See cyclic AMP.Adenosine diphosphate: See ADP.Adenosine triphosphate: See ATP.Adipocyte:（脂肪细胞）An animal cell specialized for the storage of fats(triacylglycerols).Adipose tissue:（脂肪组织）Connective tissue specialized for the storage of large amounts of triacylglycerols.ADP(adenosine diphosphate): A ribonucleoside diphosphate serving as phosphate group acceptor in the cell energy cycle.Aerobe:（需氧生物）An organism that lives in air and uses oxygen as the terminal electron acceptor in respiration.Aerobic: Requiring or occurring in the presence of oxygen.Alcohol fermentation:（乙醇发酵）The anaerobic conversion of glucose to ethanol via glycolysis.See also fermentation.Aldose:（醛糖）A simple sugar in which the carbonyl carbon atom is an aldehyde;that is, the carbonyl carbon is at one end of the carbon chain.Alkalosis:（碱中毒）A metabolic condition in which the capacity of the body to buffer is diminished;usually accompanied by an increase in blood pH.Allosteric enzyme:（变/别构效应）A regulatory enzyme, with catalytic activity modulated by the noncovalent binding of a specific metabolite at a site other than the active site.Allosteric protein:（变/别构蛋白）A protein(generally with multiple subunits)with multiple ligand-binding sites, such that ligand binding at one site affects ligand binding at another.Allosteric site:（变/别构部位）The specific site on the surface of an allosteric enzyme molecule to which the modulator or effector molecule is bound.α helix:（α-螺旋）A helical conformation of a polypeptide chain, usually right-handed, with maximal intrachain hydrogen bonding;one of the most common secondary structures in proteins.Ames test: A simple bacterial test for carcinogens, based on the assumption that carcinogens are mutagens.Amino acid activation:（氨基酸活化）ATP-dependent enzymatic esterification of the carboxyl group of an amino acid to the 3'-hydroxyl group of its corresponding tRNA.Amino acids:（氨基酸）an Amino-substituted carboxylic acids, the building blocks of proteins.Amino-terminal residue:（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:（氨基转移酶）Enzymes that catalyze the transfer of amino groups fromα-amino to α-keto acids;also called transaminases.Ammonotelic:（排氨的）Excreting excess nitrogen in the form of ammonia.Amphibolic pathway:（双向代谢途径）A metabolic pathway used in both catabolism and anabolism.Amphipathic:（双亲的）Containing both polar and nonpolar domains.Ampholyte:（两性电解质）A substance that can act as either a base or an acid.Amphoteric:（两性的）Capable of donating and accepting protons, thus able to serve as an acid or a base.Anabolisim:（合成代谢）The phase of intermediary metabolism concerned with the energy-requiring biosynthesis of cell components from smaller precursors.Anaerobe:（厌氧生物）An organism that lives without oxygen.Obligate anaerobes（专性厌氧生物）die when exposed to oxygen.Anaerobic:（厌氧的）Occurring in the absence of air or oxygen.Anaplerotic reaction:（回补反应）An enzyme-catalyzed reaction that can replenish the supply of intermediates in the citric acid cycle.Angstrom(Ǻ):（唉）A unit of length(10-8cm)used to indicate molecular dimensions.Anhydride:（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—0—X—R, where X is either carbon or phosphorus.Anion-exchange resin:（阴离子交换树脂）A polymeric resin with fixed cationic groups;used in the chromatographic separation of anions.Anomers:（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:（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:（抗体）A defense protein synthesized by the immune system of vertebrates.See also immunoglobulin.Anticodon:（反密码子）A specific sequence of three nucleotides in a tRNA, complementary to a codon for an amino acid in an mRNA.Antigen:（抗原）A molecule capable of eliciting the synthesis of a specific antibody in vertebrates.Antiparallel:（反平行）Describing two linear polymers that are opposite in polarity or orientation.Antiport:（反向转运）Cotransport of two solutes across a membrane in opposite directions.Apoenzyme:（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:（脱辅基脂蛋白）The protein component of a lipoprotein.Apoprotein:（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:（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 macromolecules.Arrestin:（抑制蛋白）A family of proteins that bind to the phosphorylated carboxyl-terminal region of serpentine receptors, preventing their interactions with G proteins and thereby terminating the signal through those receptors.Asymmetric carbon atom:（不对称碳原子）A carbon atom that is covalently bonded to four different groups and thus may exist in two different tetrahedral configurations.ATP(adenosine triphosphate): A ribonucleoside 5'-triphosphate functioning as a phosphate group donor in the cell energy cycle;carries chemical energy between metabolic pathways by serving as a shared intermediate coupling endergonic and exergonic reactions.ATP synthase:（ATP合酶）An enzyme complex that forms ATP from ADP and phosphate during oxidative phosphorylation in the inner mitochondrial membrane or the bacterial plasma membrane, and during photophosphorylation in chloroplasts.ATPase:（ATP酶）An enzyme that hydrolyzes ATP to yield ADP and phosphate;usually coupled to some process requiring energy.Attenuator:（弱化子）An RNA sequence involved in regulating the expression of certain genes;functions as a transcription terminator.Autotroph:（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.Auxin:（植物生长素）A plant growth hormone.Auxotrophic mutant(auxotroph):（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 Back-mutation:（回复突变）A mutation that causes a mutant gene to regain its wild-type base sequence.Bacteriophage(phage):（噬菌体）A virus capable of replicating in a bacterial cell.Basal metabolic rate:（基础代谢率）The rate of oxygen consumption by an animal's body at complete rest, long after a meal.Base pair:（碱基对）Two nucleotides in nucleic acid chains that are paired by hydrogen bonding of their bases;for example, A with T or U, and G with C.β conformation:（β构象）、An extended, zigzag arrangement of a polypeptide chain;a common secondary structure in proteins.β oxidation:（β氧化）Oxidative degradation of fatty acids into acetyl-CoA by successive oxidations at the β-carbon atom.β-turn:（β转角）A type of secondary structure in polypeptides consisting of four amino acid residues arranged in a tight turn so that the polypeptide turns back on itself.Bilayer:（双分子层）A double layer of oriented amphipathic lipid molecules, forming the basic structure of biological membranes.The hydrocarbon tails face inward to form a continuous nonpolar phase.Bile salts:（胆酸盐）Amphipathic steroid derivatives with detergent properties, participating in digestion and absorption of lipids.Binding energy:（吸附能）The energy derived from noncovalent interactions between enzyme and substrate or receptor and ligand.Binding site:（结合部位）The crevice or pocket on a protein in which a ligand binds.Biocytin:（生物胞素）The conjugate amino acid residue arising from covalent attachment of biotin, through an amide linkage, to a Lys residue.Biomolecule:（生物分子）An organic compound normally present as an essential component of living organisms.Biopterin:（生物喋呤）An enzymatic cofactor derived from pterin and involved in certain oxidation-reduction reactions.Biosphere:（生物圈）All the living matter on or in the earth, the seas, and the atmosphere.Biotin:（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:（分支迁移）Movement of the branch point in branched DNA formed from two DNA molecules with identical sequences.See also Holliday intermediate.Buffer:（缓冲液）A system capable of resisting changes in pH, consisting of a conjugate acid-base pair in which the ratio of proton acceptor to proton donor is near unity.C Calorie:（卡）The amount of heat required to raise the temperature of 1.0 g of water from 14.5 to 15.5 °C.One calorie(cal)equals 4.18 joules(J).Calvin cycle:（Calvin循环）The cyclic pathway used by plants to fix carbon dioxide and produce triose phosphates.cAMP: See cyclic AMP.cAMP receptor protein(CRP):（cAMP受体蛋白）A specific regulatory protein that controls initiation of transcription of the genes producing the enzymes required for a bacterial cell to use some other nutrient when glucose is lacking.Also called catabolite gene activator protein(CAP)，降解物基因活化蛋白.CAP: See catabolite gene activator protein.Capsid:（衣壳）The protein coat of a virion or virus particle.Carbanion:（碳负离子）A negatively charged carbon atom.Carbocation:（碳正离子）A positively charged carbon atom;also called a carbonium ion.Carbon-assimilation 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:（类葫罗卜素）Lipid-soluble photosynthetic pigments made up of isoprene units.Catabolism:（分解代谢）The phase of intermediary metabolism concerned with the energy-yielding degradation of nutrient molecules.Catabolite gene activator protein(CAP): See cAMP receptor protein.Catalytic site:（催化部位）See active site.Catecholamines:（儿茶酚胺类）Hormones, such as epinephrine, that are amino derivatives of catechol.Catenane:（连环体）Circular polymeric molecules with a noncovalent topological link resembling the links of a chain.Cation-exchange resin:（阳离子交换树脂）An insoluble polymer with fixed negative charges;used in the chromatographic separation of cationic substances.cDNA: See complementary DNA.Central dogma:（中心法则）The organizing principle of molecular biology: genetic information flows from DNA to RNA to protein.Centromere:（着丝粒）A specialized site within a chromosome, serving as the attachment point for the mitotic or meiotic spindle.Cerebroside(脑苷酯)Sphingolipid containing one sugar residue as a head group.Channeling:（生物合成途径限制作用)The direct transfer of a reaction product(common intermediate)from the active site of one enzyme to the active site of a different enzyme catalyzing the next step in a sequential pathway.Chemiosmotic coupling:（化学渗透偶联）Coupling of ATP synthesis to electron transfer via an electrochemical H+ gradient across a membrane.Chemotaxis（向化性）: A cell's sensing of and movement toward, or away from, a specific chemical agent.Chemotroph:（化能生物）An organism that obtains energy by metabolizing organic compounds derived from other organisms.Chiral center:（手性中心）An atom with substituents arranged so that the molecule is not superimposable on its mirror image.Chiral compound:（手性化合物）A compound that contains an asymmetric center(chiral atom or chiral center)and thus can occur in two nonsuperimposable mirror-image forms(enantiomers).Chlorophylls:（叶绿素）A family of green pigments functioning as receptors of light energy in photosynthesis;magnesium-porphyrin complexes.Chloroplasts:（叶绿体）Chlorophyll-containing photosynthetic organelles in some eukaryotic cells.Chromatin:（染色质）A filamentous complex of DNA, histones, and other proteins, constituting the eukaryotic chromosome.Chromatography:（层析）A process in which complex mixtures of molecules are separated by many repeated partitionings between a flowing(mobile)phase and a stationary phase.Chromosome:（染色体）A single large DNA molecule and its associated proteins, containing many genes;stores and transmits genetic information.Chylomicron:（乳糜微粒）A plasma lipoprotein consisting of a large droplet of triacylglycerols stabilized by a coat of protein and phospholipid;carries lipids from the intestine to the tissues.cis and trans isomers:（顺反异构体）See geometric isomers.Cistron:（顺反子）A unit of DNA or RNA corresponding to one gene.Citric acid cycle:（柠檬酸循环）A cyclic system of enzymatic.reactions for the oxidation of acetyl residues to carbon dioxide, in which formation of citrate is the first step;also known as the Krebs cycle or tricarboxylic acid cycle.Clones:（克隆）The descendants of a single cell.Cloning: The production of large numbers of identical DNA molecules, cells, or organisms, from a single ancestral DNA molecule, cell, or organism.Closed system:（封闭系统）A system that exchanges neither matter nor energy with the surroundings.See also system.Cobalamin:（钴胺素）See cocnzyme B12.Codon:（密码子）A sequence of three adjacent nucleotides in a nucleic acid that codes for a specific amino acid.Coenzyme:（辅酶）An organic cofactor required for the action of certain enzymes;often contains a vitamin as a component.Coenzyme A:（辅酶A）A pantothenic acid-containing coenzyme serving as an acyl group carrier in certain enzymatic reactions.Coenzyme B12: An enzymatic cofactor derived from the vitamin cobalamin, involved in certain types of carbon skeletal rearrangements.Cofactor(辅助因子)An inorganic ion or a coenzyme required for enzyme activity.Cognate:（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:（粘性末端）See sticky ends.Cointegrate:（共整合）An intermediate in the migration of certain DNA transposons in which the donor DNA and target DNA are covalently attached.Colligative 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:（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:（竞争性抑制作用）A type of enzyme inhibition reversed by increasing the substrate concentration;a competitive inhibitor generally competes with the normal substrate or ligand for a protein's binding site.Complementary:（互补）Having a molecular surface with chemical groups arranged to interact specifically with chemical groups on another molecule.Complementary DNA(cDNA): A DNA used in DNA cloning, usually made by reverse transcriptase;complementary to a given mRNA.Configuration:（构型）The spatial arrangement of an organic molecule that is conferred by the presence of either(1)double bonds, about which there 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 bonds.Conformation:（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 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 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:（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:（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:（组成酶）Enzymes required at all times by a cell and present at some constant level;for example, many enzymes of the central metabolic pathways.Sometimes called house-keeping enzymes.Contour length(外形长度): The length of a helical polymeric molecule as measured along the molecule's helical axis.Corticosteroids（皮质类固醇激素）Steroid hormones formed by the adrenal cortex.Cotransport:（共转运）The simultaneous transport, by a single transporter, of two solutes across a membrane.See antiport, symport.Coupled reactions:（偶联反应）Two chemical reactions that have a common intermediate and thus a means of energy transfer from one to the other.Covalent bond:（共价键）A chemical bond that involves sharing of electron pairs.Cristae:（嵴）Infoldings of the inner mitochondrial membrane.CRP（cAMP受体蛋白）See cAMP receptor protein.Cyclic AMP(cAMP): A second messenger within cells;its formation by adenylyl cyclase is stimulated by certain hormones or other molecular signals.Cyclic electron flow:（循环电子流）In chloroplasts, the light-induced flow of electrons originating from and returning to photosystem I.Cyclic photophosphorylation:（循环光合磷酸化）ATP synthesis driven by cyclic electron flow through photosystem I.Cyclin:（细胞周期蛋白）One of a family of proteins that activate cyclin-dependent protein kinases and thereby regulate the cell cycle.Cytochromes:（细胞色素）Heme proteins serving as electron carriers in respiration, photosynthesis, and other oxidation-reduction reactions.Cytokine:（细胞因子）One of a family of small secreted proteins(such as interleukins or interferons)that activate cell division or differentiation by binding to plasma membrane receptors in sensitive cells.Cytokinesis:（胞质分裂）The final separation of daughter cells following mitosis.Cytoplasm:（细胞质）The portion of a cell's contents outside the nucleus but within the plasma membrane;includes organelles such as mitochondria.Cytoskeleton:（细胞骨架）The filamentous network providing structure and organization to the cytoplasm;includes actin filaments, microtubules, and intermediate filaments.Cytosol:（细胞浆）The continuous aqueous phase of the cytoplasm, with its dissolved solutes;excludes the organelles such as mitochondria.D Dalton:（道尔顿）The weight of a single hydrogen atom(1.66 x I0-24 g).Dark reactions:（暗反应）See carbon-assimilation reactions.De novo pathway:（从头合成）Pathway for synthesis of a biomolecule, such as a nucleotide, from simple precursors;as distinct from a salvage pathway.Deamination:（脱氨基作用）The enzymatic removal of amino groups from biomolecules such as amino acids or nucleotides.Degenerate code:（兼并密码）A code in which a single element in one language is specified by more than one element in a second language.Dehydrogenases:（脱氢酶类）Enzymes catalyzing the removal of pairs of hydrogen atoms from their substrates.Deletion mutation:（删除突变）A mutation resulting from the deletion of one or more nucleotides from a gene or chromosome.Denaturation:（变性）Partial or complete unfolding of the specific native conformation of a polypeptide chain, protein, or nucleic acid.Denatured protein:（变性蛋白）A protein that has lost its native conformation by exposure to a destabilizing agent such as heat or detergent.Deoxyribonucleic acid;See DNA.Deoxyribonucleotides:（脱氧核糖核苷酸）Nucleotides containing 2-deoxyribose as the pentose component.Desaturases:（去饱和酶）Enzymes that catalyze the introduction of double bonds into the hydrocarbon portion of fatty acids.Desolvation:（脱水）In aqueous solution, the release of bound water surrounding a solute.Dextrorotatory isomer:9右旋异构体）A stercoisomer that rotates the plane of plane-polarized light clockwise.Diabetes mellitus:（糖尿病）A metabolic disease resulting from insulin deficiency;characterized by a failure in glucose transport from the blood into cells at normal glucose concentrations.Dialysis:（透析）Removal of small molecules from a solution of a macromolecule, by allowing them to diffuse through a semipermeable membrane into water.Differential centrifugation:（差速离心）Separation of cell organelles or other particles of different size by their different rates of sedimentation in a centrifugal field.Differentiation:（分化）Specialization of cell structure and function during embryonic growth and development.Diffusion:（扩散）The net movement, of molecules in the direction of lower concentration.Digestion:（消化）Enzymatic hydrolysis of major nutrients in the gastrointestinal system to yield their simpler components.Diploid:（二倍体）Having two sets of genetic information;describing a cell with two chromosomes of each type.Dipole;（双极分子）A molecule having both positive and negative charges.Diprotic acid: An acid having two dissociable protons.Disaccharide:（二糖）A carbohydrate consisting of two covalently joined monosaccharide units.Dissociation constant:（解离常数）(1)An equilibrium constant(Kd)for the dissociation of a complex of two or more biomolecules into its components;for example, dissociation of a substrate from an enzyme.(2)The dissociation constant(Ka)of an acid, describing its dissociation into its conjugate base and a proton.Disulfide bridge:(二硫桥)A covalent cross link between two polypeptide chains formed by a cystine residue(two Cys residues).0 DNA(deoxyribonucleic acid)： A polynucleotide having a specific sequence of deoxyribonucleotide units covalently joined through 3', 5'-phosphodiester bonds;serves as the carrier of genetic information.DNA chimera:（DNA嵌合）A DNA containing genetic information derived from two different species.DNA cloning: Sec cloning.DNA library:（DNA文库）A collection of cloned DNA fragments.DNA ligase：（DNA连接酶）An enzyme that creates a phosphodiester bond between the 3' end of one DNA segment, and the 5' end of another.DNA looping:（DNA出环）The interaction of proteins bound at distant sites on a DNA molecule so that the intervening DNA forms a loop.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:（DNA聚合酶）An enzyme that catalyzes template-dependent synthesis of DNA from its deoxyribonucleoside 5'-triphosphate precursors.DNA replicase system：（DNA复制酶系统）The entire complex of enzymeH and specialized proteins required in biological DNA replication.DNA supercoiling:（DNA超螺旋化）The coiling of DNA upon itself, generally as a result of bending, underwinding, or overwinding of the DNA helix.DNA transposition:（DNA转座）See transposition.domain:（结构域）A distinct structural unit of a polypeptide;domains may have separate functions and may fold as independent, compact units.Double helix:（双螺旋）The natural coiled conformation of two complementary, antiparallel DNA chains.Double-reciprocal 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, E E'°: 标准还原电位 See standard reduction potential.E.coli(Escherichia coli):（大肠杆菌）A common bacterium found in the small intestine of vertebrates;the most well-studied organism.Electrochemical gradient:（电化学梯度）The sum of the gradients of concentration and of electric charge of an ion across a membrane;the driving force for oxidative phosphorylation and photophosphorylation.Electrochemical potential:（电化学势）

The energy required to maintain a separation of charge and of concentration across a membrane.Electrogenic:（生电的）Contributing to an electrical potential across a membrane.1 1

Electron acceptor:（电子受体）A substance that receives electrons in an oxidation-reduction reaction.Electron carrier:（电子载体）A protein, such as a flavoprotein or a cytochrome, that can reversibly gain and lose electrons;functions in the transfer of electrons from organic nutrients to oxygen or some other terminal acceptor.Electron donor:（电子供体）A substance that donates electrons in an oxidation-reduction reaction.Electron transfer:（电子转移）Movement of electrons from substrates to oxygen via the carriers of the respiratory(electron transfer)chain.Electrophile:（亲电剂）An electron-deficient group with a strong tendency to accept electrons from an electron-rich group(nucleophile).Electrophoresis（电泳）: Movement of charged solutes in response to an electrical field;often used to separate mixtures of ions, proteins, or nucleic acids.Electroporation:（电穿孔法）Introduction of macromolecules into cells after rendering the cells transiently permeable by the application of a high-voltage pulse.Elongation factors:（延长因子）Specific proteins required in the elongation of polypeptide chains by ribosomes.Eluate:（流出液）The effluent from a chromatographic column.Enantiomers:（对映异构体）Stereoisomers that are nonsuperimposable mirror images of each other.End-product inhibition: See feedback inhibition.Endergonic reaction(耗能反应): A chemical reaction that consumes energy(that is, for which ΔG is positive).Endocrine glands:（内分泌腺）Groups of cells specialized to synthesize hormones and secrete them into the blood to regulate other types of cells.Endocytosis:（内吞体）The uptake of extracellular material by its inclusion within a vesicle formed by an invagination of the plasma membrane.Endonuclease:（内切核酸酶）An enzyme that hydrolyzes the interior phosphodiester bonds of a nucleic acid;that is, it acts at points other than the terminal bonds.Endoplasmic reticulum:（内质网）An extensive system of double membranes in the cytoplasm of eukaryotic cells;it encloses secretory channels and is often studded with ribosomes(rough endoplasmic reticulum).Endothermic reaction:（吸热反应）A chemical reaction that takes up heat(that is, for which ΔH is positive).Energy charge:（能荷）The fractional degree to which the ATP/ADP/AMP system is filled with high-energy phosphate groups.Energy coupling:（能量偶联）The transfer of energy from one process to anotlier.Enhancers:（增强子）DNA sequences that facilitate the expression of a given gene;2 1

may be located a few hundred, or even thousand, base pairs away from the gene.Enthalpy(H):（焓）The heat.content of a system.Enthalpy change(ΔH):（焓变）For a reaction, is approximately equal to the difference between the energy used to break bonds and the energy gained by the formation of new ones.Entropy(S):（熵）The extent of randomness or disorder in a system.Enzyme：（酶）A biomolecule, either protein or RNA, that catalyzes a specific chemical reaction.It does not affect the equilibrium of the catalyzed reaction;it enhances the rate of a reaction by providing a reaction path with a lower activation energy.Enzyme cascade:（酶级联）A series of reactions, often involved in regulatory events, in which one enzyme activates another(often by phosphorylation), which activates a third, and so on.The effect, of a catalyst activating a catalyst is a large amplification of the signal that initiated the cascade.Epimerases:（表异构酶）Enzymes that catalyze the reversible interconveraion of two epimers.Epimers:（表异构体）Two stereoisomers differing in configuration at one asymmetric center, in a compound having two or more asymmetric centers.Epithelial cell:（上皮细胞）Any cell that forms part of the outer covering of an organism or organ.Epitope:（抗原决定族）An antigenic determinant;the particular chemical group or groups within a macromolecule(antigen)to which a given antibody binds.Equilibrium:（平衡）The state of a system in which no further net change is occurring;the free energy is at a minimum.Equilibrium constant(K'eq)（平衡常数）A constant, characteristic for each chemical reaction;relates the specific concentrations of all reactants and products at equilibrium at a given temperature and pressure.Erythrocyte:（红细胞）A cell containing large amounts of hemoglobin and specialized for oxygen transport;a red blood cell.Escherichia coli: See E.coli.Essential amino acids:（必需氨基酸）Amino acids that cannot be synthesized by humans(and other vertebrates)and must be obtained from the diet.Essential fatty acids:（必需脂肪酸）The group of polyunsaturated fatty acids produced by plants, but not by humans;required in the human diet.Ethanol fermentation:（乙醇发酵）See alcohol fermentation.Eukaryote:（真核生物）A unicellular or multicellular organism with cells having a membrane-bounded nucleus, multiple chromosomes, and internal organelles.Excited state:（激发态）An energy-rich state of an atom or molecule;produced by the absorption of light energy.Exergonic reaction:（放能反应）A chemical reaction that proceeds with the release of 3 1

free energy(that is, for which ΔG is negative).Exocytosis:（胞泌作用）The fusion of an intracellular vesicle with the plasma membrane, releasing the vesicle contents to the extracellular space.Exon:（外显子）The segment of a eukaryotic gene that encodes a portion of the final product of the gene;a portion that remains after posttranscriptional processing and is transcribed into a protein or incorporated into the structure of an RNA.See intron.Exonuclease:（外切核酸酶）An enzyme that hydrolyzes only those phosphodiester bonds that are in the terminal positions of a nucleic acid.Exothermic reaction:（放热反应）A chemical reaction that releases heat(that is, for which A// is negative).Expression vector:（表达载体）See vector.F Facilitated diffusion:（协助扩散）Diffusion of a polar substance across a biological membrane through a protein transporter;also called passive diffusion or passive transport.Facultative cells:（兼性需样氧细胞）Cells that can live in the presence or absence of oxygen.FAD(flavin adenine dinucleotide)：（黄素腺嘌呤二核苷酸）The coenzyme of some oxidation-reduction enzymes;it contains riboflavin.Fatty acid:（脂肪酸）A long-chain aliphatic carboxylic acid found in natural fats and oils;also a component of membrane phospholipids arid glycolipids.Feedback inhibition:（反馈抑制）Inhibition of an allosteric enzyme at the beginning of a metabolic sequence by the end product of the sequence;also known as end-product inhibition.Fermentation:（发酵）Knergy-yielding anaerobic breakdown of a nutrient molecule, such as glucose, without net oxidation;yields lactate, ethanol, or some other simple product.Fibroblast（成纤维细胞）A cell of the connective tissue that secretes connective tissue proteins such as collagen.Fibrous proteins:（纤维状蛋白质）Insoluble proteins that serve in a protective or structural role;contain polypeptide chains tliat generally share a common secondary structure.Fingerprinting:（指纹作图）See peptide mapping.First law of thermodynamics: The law staling that in all processes, the total energy of the universe remains constant.Fischer projection formulas:（Fischer投影式）See projection formulas.5' end: The end of a nucleic acid that lacks a nucleotide bound at the 5' position of the terminal residue.4 1

Flagellum:(鞭毛)A cell appendage used in propulsion.Bacterial flagella have a much simpler structure than eukaryotic flagella, which are similar to cilia.Flavin-linked dehydrogenases:(黄素脱氢酶)Dehydrogenases requiring one of the riboflavins.coenzymes, FMN or FAD.Flavin nucleotides:（黄素核苷酸）Nucleotide coenzymes(FMN and FAD)containing riboflavin.Flavoprotein(黄素蛋白)An enzyme containing a flavin nucleotide as a tightly bound prosthetic group.Fluid mosaic model:（流动镶嵌模型）A model describing biological membranes as a fluid lipid bilayer with embedded proteins;the bilayer exhibits both structural and functional asymmetry.Fluorescence:（荧光）Emission of light by excited molecules as they revert to the ground state, FMN(flavin mononucleotide):（黄素单核苷酸）Riboflavin phosphate, a coenzyme of certain oxidation-reduction enzymes.Footprinting(足迹法)A technique for identifying the nucleic acid sequence bound by a DNA-or RNA-binding protein.Fractionation:（分级分离）The process of separating the proteins or other components of a complex molecular mixture into fractions based on differences in their physical properties, such as size, net charge, and solubility.Frame shift:（移码）A mutation caused by insertion or deletion of one or more paired nucleotides, changing the reading frame of codons during protein synthesis;the polypeptide product has a garbled amino acid sequence beginning at the mutated codon.Free energy(G):（自由能）The component of the total energy of a system that can do work at constant temperature and pressure.Free energy of activation ΔG‡(活化自由能);See activation energy.Free-energy change ΔG(自由能变化): The amount of free energy released(negative ΔG)or absorbed(positive ΔG)in a reaction at constant temperature and pressure.Free radical:（自由基）See radical.Functional group:（功能团）The specific atom or group of atoms that confers a particular chemical property on a biomolccule.Furanose:（呋喃糖）A simple sugar containing the five-membered furan ring.Fusion protein:（融合蛋白）(1)A family of proteins that facilitate membrane fusion.(2)The protein product of a gene created by the fusion of two distinct genes or portions of genes.Futile cycle:（无效循环）A set of enzyme-catalyzed cyclic reactions that results in release of thermal energy by the hydrolysis of ATP.5 1

G G proteins:（G蛋白）A family of heterotrimeric GTP-binding proteins that act in intracellular signaling pathways.Commonly, ligand binding to a serpentine receptor induces the exchange of GTP for bound GDP, enabling the G protein to activate a downstream enzyme in a signaling pathway.G proteins have intrinsic GTPase activity, and therefore self-inactivate.ΔG’°:(标准自由能变化)See standard free-energy change.Gametes:（配子）Reproductive cells with a haploid gene content;sperm or egg cells.Gangliosides:（神经节苷脂）Sphingolipids, containing complex oligosaccharides as head groups;especially common in nervous tissue.Gel filtration:（凝胶过滤）See size-exclusion chromatography.（分子排阻层析）Gene:（基因）A chromosomal segment, that codes for a single functional polypeptide chain or RNA molecule.Gene expression:（基因表达）Transcription, and in the case of proteins, translation, to yield the product of a gene;a gene is expressed when its biological product is present and active.Gene splicing:（基因拼接）The enzymatic attachment of one gene, or part.of a gene, to another.General acid-base catalysis:（广义酸碱催化）Catalysis involving proton transfer(s)to or from a molecule other than water.Genetic code:（遗传密码）The set of triplet code words in UNA(or mRNA)coding for the amino acids of proteins.Genetic information:（遗传信息）The hereditary information contained in a sequence of nucleotide bases in chromosomal DNA or RNA.Genetic map:（遗传图谱）A diagram showing the relative sequence and position of specific genes along a chromosome.Genome:（基因组）All the genetic information encoded in a cell or virus.Genomic library:（基因组文库）A DNA library containing DNA segments representing all(or most)of the sequences in an organism's genome.Genotype:（基因性或遗传型）The genetic constitution of an organism, as distinct from ils physical characteristics, or phenotype.Geometric isomers:（几何异构体）Isomers related by rotation about a double bond;also called cis and trans isomers.Germ-line cell(生殖系细胞)A type of animal cell that is formed early in embryogenesis and may multiply by mitosis or may produce, by meiosis, cells that develop into gametes(egg or sperm cells).Globular proteins：（球蛋白）Soluble proteins with a globular(somewhat rounded)shape.Glucogenic amino acids:（生糖氨基酸）Amino acids with carbon chains that can be 6 1

metabolically converted into glucose or glycogen via gluconeogenesis.Gluconeogenesis:(糖异生)The biosynthesis of a carbohydrate from simpler, noncarbohydrate precursors such as oxaloacetate（草酰乙酸）or pyruvate（丙酮酸）.Glycan:（聚糖）Another term for polysaccharide;a polymer-of monosaccharide units joined by glycosidic bonds, Glycerophospholipid:（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 to C-3.Glycoconjugate:(复合糖)A compound containing a carbohydrate component bound covalently to a protein or lipid, forming a glycoprotein or glycolipids.Glycolipid:（糖脂）A lipid containing a carbohydrate group, Glycolysis:（糖酵解）The catabolic pathway by which a molecule of glucose is broken down into two molecules of pyruvate.Glycoprotein(糖蛋白)A protein containing a carbohydrate group.Glycosaminoglycan:（糖胺聚糖）A heteropolysaccharide of two alternating units: one is either N-acetylglucosamine or N-acetylgalactosamine;the other is a uronic acid(usually glucuronic acid).Formerly called mucopolysaccharide.(粘多糖)Glycosidic bonds:（糖苷键）Bonds between a sugar and another molecule(typically an alcohol, purine, pyrimidine, or sugar)through an intervening oxygen.Glyoxylate cycle:(乙醛酸循环)A variant of the citric acid cycle, for the net conversion of acetate into succinate and, eventually, new carbohydrate;present in bacteria and some plant cells.Glyoxysome:（乙醛酸体）A specialized peroxisome containing the enzymes of the glyoxylate cycle;found in cells of germinating seeds.Golgi complex:（高尔基复合体）A complex membranous organelle of eukaryotic cells;functions in the posttranslational modification of proteins and their secretion from the cell or incorporation into the plasma membrane or organellar membranes.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:（基粒）Stacks of thylakoids（类囊体）, flattened membranous sacs or disks, in chloroplasts.Ground state:（基态）The normal, stable form of an atom or molecule;as distinct from the excited state.Group transfer potential:（基团转移力）A measure of the ability of a compound to donate an activated group(such as a phosphate or acyl group);generally expressed as the standard free energy of hydrolysis.H Half-life:（半衰期）The time required for the disappearance or decay of one-half of a 7 1

given component in a system.Haploid:（单倍体）Having a single set of genetic information;describing a cell with one chromosome of each type.Hapten:（半抗原）A small molecule which, when linked to a larger molecule, elicits an immune response.Haworth perspective formulas:（Haworth透视式）A method for representing cyclic chemical structures so as to define the configuration of each substituent group;the method commonly used for representing sugars.Helicase(解螺旋酶)An enzyme that, catalyzes the separation of strands in a DNA molecule before replication.Heme:（血红素）The iron-porphyrin prosthetic group of heme proteins.Heme protein:（血红素蛋白）A protein containing a heme as a prosthetic group.Hemoglobin:（血红蛋白）A heme protein in erythrocytes;functions in oxygen transport.Henderson-Hasselbalch equation: An equation relating the pH, the pKa, and the ratio of the concentrations of the proton-acceptor(A+)and proton-donor(HA)species in a solution.Hepatocyte(肝细胞)The major cell type of liver tissue.Heteroduplex DNA(异源双链DNA)Duplex DNA containing complementary strands derived from two different DNA molecules with similar sequences, often as a product of genetic recombination.Heteropolysaccharide:（杂多糖）A polysaccharide containing more than one type of sugar.Heterotroph:（异养生物）An organism that requires complex nutrient molecules, such as glucose, as a source of energy and carbon.Heterotropic:（异促的）Describes an allosteric modulator that is distinct from the normal ligand.Heterotropic enzyme:（异促酶）An allosteric enzyme requiring a modulator other than its substrate.Hexose:（己糖）A simple sugar with a backbone containing six carbon atoms.High-energy compound:（高能化合物）A compound that on hydrolysis undergoes a large decrease in free energy under standard conditions.High-performance liquid chromatography(HPLC)：（高效液相色谱）Chromatographic procedure, often conducted at relatively high pressures, using automated equipment that permits refined and highly reproducible profiles, Hill reaction:（希尔反应）The evolution of oxygen and the photoreduction of an artificial electron acceptor by a chloroplast preparation in the absence of carbon dioxide.Histones:（组蛋白）The family of five basic proteins that associate tightly with DNA in the chromosomes of all eukaryotic cells, 8 1

Holliday intermediate（赫利地中间物）An intermediate in genetic recombination in which two double-stranded DNA molecules are joined by virtue of a reciprocal crossover involving one strand of each molecule.Holoenzyme:（全酶）A catalytically active enzyme including all necessary subunits, prosthetic groups, and cofactors.Homeobox:（同源框）A conserved DNA sequence of 180 base pairs encoding a protein domain found in many proteins that play a regulatory role in development.Homeodomain:（发育同源结构域）The protein domain encoded by the homeobox.Homeostasis:（内稳态）The maintenance of a dynamic steady state by regulatory mechanisms that compensate for changes in external circumstances.Homeotic genes:（同源框基因）Genes that regulate the development of the pattern of segments in the Drosophila body plan;similar genes are found in most vertebrates.Homologous genetic recombination:（同源遗传重组）Recombination between two DNA molecules of similar sequence, occurring in all cells;occurs during meiosis and mitosis in eukaryotes.Homologous proteins:（同源蛋白）Proteins having sequences and functions similar in different species;for example, the hemoglobins.Homopolysaccharide:（同多糖）A polysaccharide made up of only one type of monosaccharide unit.Homotropic:(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:（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.Hyaluronic acid:（透明质酸）A high molecular weight, acidic polysaccharide typically composed of the alternating disaccharide GlcUA(β1→3)GlcNAc, Hyaluronic acid is a major component of the extracellular matrix, and forms larger complexes(proteoglycans)with proteins and other acidic polysaccharides.Hydrogen bond:（氢键）A weak electrostatic attraction between one electronegative atom(such as oxygen or nitrogen)and a hydrogen atom covalently linked to a second electronegative atom.9 1

Hydrolases:（水解酶）Enzymes(proteases, lipases, phosphatases, nucleases, for example)that catalyze hydrolysis reactions.Hydrolysis:（水解）Cleavage of a bond, such as an anhydride or peptide bond, by the addition of the elements of water, yielding two or more products, Hydronium ion:（水合氢离子）The hydrated hydrogen ion(H3O+).Hydropathy index:（亲水指数）A scale that expresses the relative hydrophobia and hydrophilic tendencies of a chemical group.Hydrophilic：（亲水的）Polar or charged;describing molecules or groups that associate with(dissolve easily in)water.Hydrophobic:（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 effect(增色效应)The large increase in light absorption at 260 nm occurring as a double-helical DNA is melted(unwound).Hypoxia:（低氧）The metabolic condition in which the supply of oxygen is severely limited.I Immune response:（免疫反应）The capacity of a vertebrate to generate antibodies to an antigen, a macromolecule foreign to the organism.Immunoglobulin(免疫球蛋白)An antibody protein generated against, and capable of binding specifically to an antigen.in vitro:（体外）“In glass”;that is, in the test tube.in vivo:（体内）“In life”;that is, in the living cell or organism.Induced fit:（诱导契合）A change in the conformation of an enzyme in response to substrate binding that renders the enzyme catalytically active;also used to denote changes in the conformation of any macromolecule in response to ligand binding such that the binding site of the macromolecule better conforms to the shape of the ligand.Indncer:（诱导物）A signal molecule that, when bound to a regulatory protein, produces an increase in the expression of a given gene.Induction:（诱导）An increase in the expression of a gene in response to a change in the activity of a regulatory protein.Informational macromolecules:（信息大分子）Biomolecules containing information in the form of specific sequences of different monomers;for example, many proteins, lipids, polysaccharides, and nucleic acids.Initiation codon（起始密码）AUG(sometimes GUG in prokaryotes);codes for the first amino acid in a polypeptide sequence: N-formylmethionine in prokaryotes, and methionine in eukaryotes.0 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(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.Insertion mutation:（插入突变）A mutation caused by insertion of one or more extra bases, or a mutagen, between successive bases in DNA.Insertion sequence:（插入序列）Specific base sequences at either end of a transposable segment of DNA.Integral proteins:（膜整体蛋白）Proteins firmly bound to a membrane by hydrophobic interactions;as distinct from peripheral proteins.Integrin:（整连蛋白）One of a large family of heterodimeric transmembrane proteins that mediate adhesion of cells to other cells or to the extracellular matrix.Intercalating mutagen:（嵌入突变）A mutagen that inserts itself between successive bases in a nucleic acid, causing a frame-shift mutation.Intercalation:（嵌入）Insertion between stacked aromatic or planar rings;for example, the insertion of a planar molecule between two successive bases in a nucleic acid.Iinterferons:（干扰素）A class of glycoproteins with antiviral activities.Intermediary metabolism:（中间代谢）In cells, the enzyme-catalyzed reactions that extract chemical energy from nutrient molecules and utilize it to synthesize and assemble cell components.Intron(intervening sequence)（内含子，间隔序列）A sequence of nucleotides in a.gene that is transcribed but excised before the gene is translated.Ion channel:（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:（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.Ionizing radiation（电离辐射）A type of radiation, such as x rays, that causes loss of electrons from some organic molecules, thus making them more reactive.Ionophore:（离子载体）A compound that binds one or more metal ions and is capable of diffusing across a membrane, carrying the bound ion.Iron-sulfur center:（铁硫中心）A prosthetic group of certain redox proteins involved in electron transfers;Fe2+ or Fe3+ is bound to inorganic sulfur and to Cys groups in the protein.Isoelectric focusing（等电聚焦）An electrophoretic method for separating macromolccules on the basis of their isoelectric pH.1 2

Isoelectric pH(isoelectric point)(等电点)The pH at which a solute has no net electric charge and thus does not move in an electric field, Isoenzymes:（同工酶）See isozymes.Isomerases:（异构酶类）Enzymes that catalyze the transformation of compounds into their positional isomers.Isomers:（异构体）Any two molecules with the same molecular formula, but a different arrangement of molecular groups.Isoprene:（异戊二烯）The hydrocarbon 2-methyl-1, 3-butadiene, a recurring structural unit of the terpenoid biomolecules.Isoprenoid:（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:（等温的）Occurring at constant temperature.Isotopes:（同位素）Stable or radioactive forms of an element that differ in atomic weight but are otherwise chemically identical to the naturally abundant form of the clement;used as tracers.Isozymes:（同工酶）Multiple forms of an enzyme that catalyze the same reaction but differ from each other in their amino acid sequence, substrate affinity, Vm, and / or regulatory properties;also called isoenzymes.K Keratins;(角蛋白)Insoluble protective or structural proteins consisting of parallel polypeptide chains in α-helical or β conformations.Ketogenic amino acids（生酮氨基酸）Amino acids with carbon skeletons that can serve as precursors of the ketone bodies.Ketone bodies:（酮体）Acetoacetate, D-β-hydroxybutyrate, and acetone;water-soluble fuels normally exported by the liver but overproduced during fasting or in untreated diabetes mellitus.Ketose:（酮糖）A simple monosaccharide in which the carbonyl group is a ketone.Ketosis:（酮尿症）A condition in which the concentration of ketone bodies in the blood, tissues, and urine is abnormally high.Kinases:（激酶）Enzymes that catalyze the phosphorylation of certain molecules by ATP.Kinetics:（动力学）The study of reaction rates.Krebs cycle:（Krebs 循环）See citric acid cycle.L Lagging 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 reactants.2 2

Leader:（前导序列）A short sequence near the amino 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 replication, is synthesized in the same direction in which the replication fork moves.Leaky mutant:（渗漏突变）A mutant gene that gives rise to a product with a detectable level of biological activity, Leaving group:（离去基团）The departing or displaced molecular group in a unimolecular elimination or a bimolecular substitution reaction.Lectin（凝集素）A protein that binds a carbohydrate, commonly an oligosaccharide, with very high affinity and specificity, mediating cell-cell interactions.Lethal mutation:（致死突变）A mutation that inactivates a biological function essential to the life of the cell or organism.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:（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 isomer:（左旋异构体）A stercoisomer that rotates the plane of plane-polarized light counterclockwise.Ligand: A small molecule that binds specifically to a larger one;for example, a hormone is the ligand for its specific protein receptor.Ligases:（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: An algebraic transform of the Michaells-Menten equation, allowing determination of Vmax and Km by extrapolation of [S] to infinity.Linking number:(连接数)The number of times one closed circular DNA strand is wound about another;the number of topological links holding the circles together.Lipases:（脂酶）Enzymes that catalyze the hydrolysis of triacylglycerols.Lipid:（脂）A small water-insoluble biomolecule generally containing fatty acids, st.erols, or isoprenoid compounds.Lipoate(lipoic acid)（硫辛酸）A vitamin for some microorganisms;an intermediate carrier of hydrogen atoms and acyi groups hi a-keto acid dehydrogenases.Lipoprotein（脂蛋白）A lipid-protein aggregate that serves to carry water-insoluble lipids in the blood.The protein component alone is an apolipoprotein.Liposome:（脂质体）A small, spherical vesicle composed of a phospholipid bilayer, which forms spontaneously when phospholipids are suspended in an aqueous buffer.3 2

Low-energy phosphate compound:（低能化合物）A phosphorylated compound with a relatively small standard free energy of hydrolysis.Lyases:（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:（淋巴细胞）A subclass of leukocytes involved in the immune response.B lymphocytes synthesize and secrete antibodies;T lymphocytes either play a regulatory role in immunity or kill foreign and virus-infected cells.Lysis:（裂解）Destruction of a cell's plasma membrane or of a bacterial cell wall, releasing the cellular contents and killing the cell.Lysosome:（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 Macromolecule:（大分子）A molecule having a molecular weight in the range of a few thousand to many millions.Matrix:（基质）The aqueous contents of a cell or organelle(the mitochondrion, for example)with dissolved solutes.Meiosis:（减数分裂）A type of cell division in which diploid cells give rise to haploid cells destined to become gametes.Membrane potential(Vm):（膜电位）The difference in electrical potential across a biological membrane, commonly measured by the insertion of a microelectrode.Typical membrane potentials vary from —25 mV(by convention, the negative sign indicates that the inside is negative relative to the outside)to greater than —100 mV across some plant vacuole membranes.Membrane transport:（膜转运）Movement of a polar solute across a membrane via a specific membrane protein(a transporter).Messenger RNA(mRNA):（信使RNA）A class of RNA molecules, each of which is complementary to one strand of DNA;carries the genetic message from the chromosome to the ribosomes, Metabolism(新陈代谢)The entire set of enzyme-catalyzed transformations of organic molecules in living cells;the sum of anabolism and catabolism.Metabolite:（代谢物）A chemical intermediate in the enzyme-catalyzed reactions of metabolism.Metalloprotein:（金属蛋白）A protein having a metal ion as its prosthetic group.Metamerism:（分节）Division of the body into segments;in insects, for example.Micelle:（微团）An aggregate of amphipathic molecules in water, with the nonpolar portions in the interior and the polar portions at the exterior surface, exposed to water.Michaelis constant(Km)（米氏常数）The substrate concentration at which an enzyme-catalyzed reaction proceeds at one-Iialf its maximum velocity.4 2

Michaelis-Menten equation（米氏方程）The equation describing the hyperbolic dependence of the initial reaction velocity, V, on substrate concentration, [S], in many enzyme-catalyzed reactions.Michaelis-Menten kinetics:（米氏动力学）A kinetic pattern in which the initial rate of an enzyme-catalyzed reaction exhibits a hyperbolic dependence on substrate concentration.Microbodies:（微体）Cytoplasmic, membrane-bounded vesicles containing peroxide-forming and peroxide-destroying enzymes;include lysosomes, peroxisomes, and glyoxysomes.Microfilaments:（微丝）Thin filaments composed of actin, found in the cytoplasm of eukaryotic cells;serve in structure and movement.Microtubules:（微管）Thin tubules assembled from two types of globular tubulin subunits;present, in cilia, flagella, centrosomes, and other contractile or motile structures.Mismatch(碱基错配)a base pair in a nucleic acid that cannot form normal Watson-Crick pairs.Mismatch repair:(错配修复)an enzymatic system for repairing base mismatches in DNA.Mitochondrion:（线粒体）Membrane-bounded organelle in the cytoplasm of eukaryotes;contains the enzyme systems required for the citric acid cycle, fatty acid oxidation, electron transfer, and oxidative phosphorylation.Mitosis:（有丝分裂）The multistep process in eukaryotic cells that results in the replication of chromosomes and cell division, Mixed-function oxidases:（混合功能氧化酶）Enzymes(a inonooxygenase, for example)that catalyze reactions in which two reductants, one of which is generally NADPH, the other the substrate, are oxidized.One oxygen atom is incorporated into the product, the other is reduced to H^O.These enzymes often employ cylochrome P-450 to cany electrons from NADPH to 0^.Mixed inhibition:（混合抑制）The reversible inhibition pattern resulting when an inhibitor molecule can bind to either the free enzyme or to the enzyme-substrate complex(not necessarily with the same affinity).Modulator:（调节物）A Metabolite that, when bound to the allosteric site of an enzyme, alters its kinetic characteristics.Molar solution:（摩尔溶液）One mole of solute dissolved in water to give a total volume of 1000 mL.Mole:（摩尔）One gram molecular weight of a compound.See Avogadro's number.Monoclonal antibodies:（单克隆抗体）Antibodies produced by a cloned hybridoma cell, which therefore are identical and directed against the same epitope of the antigen.Monolayer:（单分子层）A single layer of oriented lipid molecules.Monoprotic acid: An acid having only one dissociable proton-5 2

Monosaccharide:（单糖）A carbohydrate consisting of I single sugar unit.mRNA: See messenger RNA.Mucopolysaccharide:（粘多糖）An older name for a glycosaminoglycan.Multienzyme system:（多酶系统）A group of related enzyme;participating in a given metabolic pathway.Mutarotation:（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（变位酶）: Enzymes that catalyze the transposition of functional groups.Mutation: An inheritable change in the nucleotide sequence of a chromosome.Myofibril:（肌原纤维）A unit of thick and thin filaments of muscle fibers.Myosin:（肌球蛋白）A contractile protein;the major component of the thick filaments of muscle and other actin-myosin systems.N NAD, NADP(nicotinamide adenine dinucleotide, nicotinamide adenine dinucleotide phosphate): Nicotinaniide-containing coenzyme: functioning as carriers of hydrogen atoms and electrons in some oxidation-reduction reactions.Native conformation:（天然构象）Ttie biologically active conformation of a macromolecule.Negative cooperativity:（负协同性）A phenomenon of some inultisubunit enzymes or proteins in which binding of a ligand or substrate to one subunit impairs binding to another subunit.Negative feedback:（负反馈）Regulation of a biochemical pathway achieved when a reaction product.inhibits an earlier step in the pathway.Neuron:（神经元）A cell of nervous tissue specialized for transmission of a nerve impulse.Neurotransmitter:（神经递质）A low molecular weight compound(usually containing nitrogen)secreted from the terminal of a neuron and bound by a specific receptor in the next neuron;serves to transmit a nerve impulse.Nicotinamide adenine dinucleotide, nicotinamide adenine dinucleotide phosphate: See NAD,NADP.Ninhydrin 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 by nitrogen-fixing organisms.Nitrogenase complex:（固氮复合物）A system of enzymes capable of reducing atmospheric nitrogen to ammonia in the presence of ATP.6 2

Noncyclic electron flow:（非环式电子流）The light-induced tlow of electrons from water to NADP^ in oxygen-evolving photosynthesis;it involves both photosystems I and II.Nonessential amino acids:（非必需氨基酸）Amino acids tliat can be made by humans and other vertebrates from simpler precursors, and are thus not required in the diet.Nonheme iron proteins:（非血红素铁蛋白）Proteins, usually acting in oxidation-reduction reactions, containing iron but no porphyrin groups.Nonpolar:（非极性的）Hydrophobic;describing molecules or groups that are poorly soluble in water.Nonsense codon:（无义密码）A codon that docs not specify an amino acid, but signals the termination of a polypeptide chain.Nonsense mutation:（无义突变）A mutation that results in the premature termination of a polypeptide chain.Nonsense suppressor（无义抑制）A mutation, usually in the gene for a tRNA, that, causes an amino acid to be inserted into a polypeptide in response to a termination codon.Nuclear magnetic resonance(NMR)spectroscopy（核磁共振谱）A technique that utilizes certain quantum mechanical properties of atomic nuclei to study the structure and dynamics of the molecules of which they are a part.Nucleases:（核酸酶）Knzymes that hydrolyze the internucicotidc(phosphodiester)linkages of nucleic acids.Nucleic acids:（核酸）Biologically occurring polynucleotides in which the nucleotide residues are linked in a specific sequence by phosphodiester bonds;DNA and RNA.Nucleoid:（拟核）In bacteria, the nuclear zone that contains the chromosome but has no surrounding membranc-Nucleolus:（核仁）A densely staining structure in the nucleus of eukaryotic cells;involved in rRNA synthesis and ribosome formation.Nucleophile:（亲核剂）An electron-rich group with a strong tendency to donate electrons tu an electron-deficient nucleus(electrophilc);the entering reactant in a bimolecular substitution reaction.Nucleoplasm:（核质）The portion of a cell's contents enclosed by the nuclear membrane;also called the nuclear matrix.Nucleoside:（核苷）A compound consisting of a purinc or pyrimidine base cuvalently linked to a pentose.Nucleoside diphosphate kinase:（核苷二磷酸激酶）An enzyme that catalyzes the transfer of the terminal phosphate of a nucleoside 5'-triphosphate to a nucleoside 5'-diphosphate.7 2

Nucleoside diphosphate sugar:（核苷二磷酸糖）A coenzymelike carrier of a sugar molecule, functioning in the enzymatic synthesis of polysaccharides and sugar derivatives.Nucleoside monophosphate kinase:（核苷一磷酸激酶）An enzyme that catalyzes the transfer of the termi-nal phosphate of ATP to a nucleoside 5'-monophosphate.Nucleosome:（核小体）Structural unit for packaging chromatin;consists of a UNA strand wound around a histone core.Nucleotide:（核苷酸）A nucleoside phosphorylated at one of its pentose hydroxyl groups.Nucleus:（细胞核）In cukaryotes, a membrane-bounded organellc that contains chromosomes.O Oligomer:(寡聚体)A short polymer, usually of amino acids, sugars, or nucleotides;the definition of “short” is somewhat arbitrary, but usually less than 50 subunits.Oligomeric protein:(寡聚蛋白)A multisubunit protein having two or more identical polypeptide chains.Oligonucleotide（寡核苷酸）: A short polymer of nucleotides(usually less than 50).Oligopeptide:（寡肽）A few amino acids joined by peptide bonds.Oligosaccharide:（寡糖）Several monosaccharide groups joined by glycosidic bonds.Oncogene:（致癌基因）A cancer-causing gene;any of several mutant genes that, cause cells to exhibit, rapid, uncontrolled proliferation.See also proto-oncogene.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(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:（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 activity:（光学活性）The capacity of a substance to rotate the plane of plane-polarized light.Optimum pH:（最适pH）The characteristic pH at which an enzyme has maximal catalytic activity.Organelles(细胞器)Membrane-bounded structures found in eukaryotic cells;contain enzymes and other components required for specialized cell functions.Origin:（起始位点）The nucleotide sequence or site in DNA where DNA replication is 8 2

initiated.Osmosis;（渗透作用）Bulk flow of water through a semi-permeable membrane into another aqueous compartment containing solute at a higher concentration.Osmotic pressure（渗透压）: Pressure generated by the osmotic flow of water through a semipermeable membrane into an aqueous compartment containing solute at a higher concentration.Oxidases:（氧化酶）Enzymes that catalyse oxidation reactions in which molecular oxygen serves as the electron acceptor, but neither of the oxygen atoms is 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:（氧债）The extra oxygen(above the normal resting level)consumed in the recovery period after strenuous physical exertion.Oxygenases:（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 catalyzed by a dioxygenase, both 0 atoms are incorporated into the product.Compare oxidases.P

Palindrome（回文结构）: A segment of duplex DNA in which the base sequences of the two strands exhibit twofold rotational symmetry about an axis.Partition coefficient（分配系数）: A constant that expresses the ratio in which a given solute will be partitioned or distributed between two given immiscible liquids at equilibrium.Pathogenic:（病原性的）Disease-causing.Pentose:（戊糖）A simple sugar with a backbone containing five carbon atoms.Pentose phosphate pathway（磷酸戊糖途径）: A pathway that serves to interconvert hexoses and pentoses and is a source of reducing equivalents and pentoses for biosynthetic processes;present, in most organisms.Also called the phosphogluconate pathway.Peptidases:（肽酶）Enzymes that hydrolyze peptide bonds.Peptide:（肽）Two or more ammo acids covaleiitly joined by peptide bonds.Peptide bond（肽键）A substituted amide linkage between the a-amino group of one amino acid and the a-carboxyl group of another, with the elimination of the elements of 9 2

water, Peptide mapping:（肽指纹图）The characteristic two-dimensional pattern(on paper or gel)formed by the separation of a mixture of peptides resulting from partial hydrolysis of a protein;also known as peptide fingerprinting.Peptidoglycan:（肽聚糖）A major component of bacterial cell walls;generally consists of parallel heteropolysaccharides cross-linked by short peptides.Peripheral proteins:（外周蛋白）Proteins that are loosely or reversibly bound to a membrane by hydrogen bonds or electrostatic forces;generally water-soluble once released from the membrane.Permeases:（透过酶）See transporters.Peroxisome:（过氧化物酶体）Membrane-bounded organelle in the cytoplasm of cukaryotic cells;contains peroxide-forming and peroxide-destroying enzymes.pH: The negative logarithm of the hydrogen ion concentration of an aqueous solution.Phage: See bacteriophage.Phenotype:（表型）The observable characteristics of an organism.Phosphatases:（磷酸酶）Enzymes that hydrolyze a phosphate ester or anhydride, releasing inorganic phosphate, Pi.Phosphodiester linkage:（磷酸二酯键）A chemical grouping that contains two alcohols esterified to one molecule of phosphoric acid, winch thus serves as a bridge between them.Phosphogluconate pathway:（磷酸己糖途径）An oxidative pathway beginning with glucose 6-phosphate and leading, via 6-phosphogluconate, to pentose phosphates and yielding NADPH.Also called the pentose phosphate pathway.Phospholipid:（磷脂）A lipid containing one or more phosphate groups.Phosphorolysis:（磷酸解）Cleavage of a compound with phosphate as the attacking group;analogous to hydrolysis.Phosphorylases;Enzymes that catalyze phosphorolysis(defined above).Phosphorylation（磷酸化作用）Formation of a phosphate derivative of a biomolecule, usually by enzymatic transfer of a phosphoryl group from ATP.Phosphorylation potential(ΔGp)（磷酸化能力）: The actual free-energy change of ATP hydrolysis under the nonstandard conditions prevailing within a cell.Photochemical reaction center（光化学反应中心）The part of a photosynthetic complex where the energy of an absorbed photon causes charge separation, initiating electron transfer.Photon:（光子）The ultimate unit(a quantum)of light energy.Photophosphorylation（光合磷酸化）The enzymatic formation of ATP from ADP coupled to the light-dependent transfer of electrons in photosynthetic cells.Photoreduction（光还原）The light-induced reduction of an electron acceptor in phot.osynthetic cells.0 Photorespiration（光呼吸）Oxygen consumption occurring in illuminated temperate-zone plants, largely due to oxidation ofphosphoglycolate.Photosynthesis（光合作用）The use of light energy to produce carbohydrates from carbon dioxide and a reducing agent sucli as water.Photosynthetic phosphorylation（光合磷酸化）See photophosphorylation.Photosystem（光系统）In photosynthetic cells, a functional set of light-absorbing pigments and its reaction center.Phototroph（光能生物）An organism that.can use the energy of light to synthesize its own fuels from simple molecules such as carbon dioxide, oxygen, and water;as distinct from a chemotroph.pKa: The negative logarithm of an equilibrium constant.Plasma membrane(质膜)The exterior membrane surrounding the cytoplasm of a cell.Plasma proteins（血浆蛋白）The proteins present in blood plasma.Plasmalogen A phospholipid with an alkenyl ether substituent on the C-l of glyccrol.Plasmid（质粒）An extrachromosomal, independently replicating, small circular DNA molecule;commonly employed in genetic engineering.Plastid（质体）In plants, a self-replicating organelle;may differentiate into a chloroplast.Platelets（血小板）Small, enucleated cells that initiate blood clotting;they arise from cells called megakaryocytes in the bone marrow.Also known as thrombocytes.Pleated sheet（折叠片）The side-by-side, hydrogen-bonded arrangement of polypeptide chains in the extended 0 conformation.Plectonemic: A structure in a molecular polymer in which there is a net twisting of strands about each other in some simple and regular way.Polar（极性的)Hydrophilic, or “water-loving”;describing molecules or groups that are soluble in water.Polarity:（极性）(1)In chemistry, the nonuniform distribution of electrons in a molecule;polar molecules are usually soluble in water.(2)In molecular biology, the distinction between the 5' and 3' ends of nucleic acids.Poly(A)tail: A length of adenosine residues added to the 3' ends of many mRNAs in eukaryotes(and sometimes in bacteria).Polycistronic mRNA（多顺反子mRNA）A contiguous mRNA with more than two genes that can be translated into proteins.Polyclonal antibodies(多克隆抗体)A heterogeneous pool of antibodies produced in an animal by a number of different.B lymphocytes in response to an antigen.Different antibodies in the pool recognize different parts of the antigen.Polylinker（多连接物）A short, often synthetic, fragment of DNA containing recognition sequences for several restriction endomicleases.1 3

Polymerase chain reaction(PCR)（聚合酶链式反应）A repetitive procedure that results in a geometric amplification of a specific DNA sequence.Polymorphic（多态性的）Describing a protein for which amino acid sequence variants exist in a population of organisms, but the variations do not destroy the protein's function.Polynucleotide（多核苷酸）A covalently linked sequence of nucieotides in which the 3' hydroxyl of the pentose of one nucleotide residue is joined by a phosphodiester bond to the 5' hydroxyl of the pentose of the next residue.Polypeptide（多肽）A long chain of amino acids linked by pcptide bonds;the molecular weight, is generally less than 10,000.Polyribosome（多核糖体）See polysome.Polysaccharide（多糖）A linear or branched polymer of monosaccharide units linked by glycosidic bonds.Polysome(polyribosome): A complex of an inRNA molecule and two or more ribosomes.P/0 ratio（磷/氧比）The number of moles of ATP formed in oxidative phosphorylation per gO^ reduced(thus, per pair of electrons passed to Oa).Experimental values used in this text are 2.5 for passage of electrons from NADH to(X, and 1.5 for passage of electrons from FADH to 0^, Some textbooks use the integral values of 3.0 and 2.0.Porphyria（卟啉症）Genetic condition resulting from the lack of one or more enzymes required to synthesize porphyrins.Porphyrin:（卟啉）Complex nitrogenous compound containing four substituted pyrroles covalently joined into a ring;often complexed with a central metal atom.Positive cooperativity（正协同性）A phenomenon of some multisubunit enzymes or proteins in which binding of a ligand or substrate to one subunit.facilitates binding to another subunit.Posttranscriptional processing（转录后加工）The enzymatic processing of the primary RNA transcript, producing functional mRNA, tRNA, and/or rRNA molecules.Posttranslational modification（翻译后修饰）Enzymatic processing of a polypeptide chain after translation from its mRNA.Primary structure（一级结构）A description of the covalent backbone of a polymer(macromolecule), including the sequence of monomeric subunits and any interchain and intrachain covalent bonds.Primary transcript（原初转录本）The immediate RNA product of transcription before any posttranscriptional processing reactions.Primase（引物酶）: An enzyme that catalyzes the formation of RNA oligonucleotides used as primers by DNA polymerascs.Primer（引物）A short oligomer(of sugars or nucieotides, for example)to which an enzyme adds additional monomeric subunits.2 3

Primer terminus（引物末端）The end of the primer to which monomeric suhunits are added.Primosome（引发体）An enzyme complex that synthesizes the primers required for lagging strand DNA synthesis.Probe（探针）A labeled fragment of nucleic acid containing a nucleotide sequence complementary to a gene or genomic sequence that one wishes to detect in a hybridization experiment, Processivity（持续合成能力）For any enzyme tliat catalyzes the synthesis of a biological polymer, the property of adding multiple subunits to the polymer without dissociating from the substrate.Prochiral molecule（原手性化合物）A symmetric molecule that can react asymmetrically with an enzyme having an asymmetric active site, generating a chiral product.Projection formulas（透视式）A method for representing molecules to show the configuration of groups around chiral centers;also known as Fischer projection formulas.Prokaryote（原核生物）A bacterium;a unicellular organism with a single chromosome, no nuclear envelope, and no membrane-bounded organelles.Promoter（启动子）A DNA sequence at.which RNA polymerase may bind, leading to initiation of transcription.Proofreading（校对）The correction of errors in the synthesis of an information-containing biopolymer by removing incorrect monomeric subunits after they have been covalent.ly added to the growing polymer.Prostaglandins（前列腺素）A class of lipid-soluble, hormonelike regulatory molecules derived from arachidonate and other polyunsaturated fatty acids.Prosthetic group（辅基）A metal ion or an organic compound(other than an amino acid)that is covalently bound to a protein and is essential to its activity.Proteasome（蛋白酶体）Supramolecular assembly of enzymatic complexes that.function in the degradation of damaged or unneeded cellular proteins.Protein（蛋白质）A macromolecule composed of one or more polypeptide chains, each with a characteristic sequence of amino acids linked by peptide bonds, Protein kinases（蛋白激酶）Enzymes that transfer the terminal phosphoryl group of ATP or another nucleoside tnphosphate to a Ser, Thr, Tyr, Asp, or His side chain in a target protein, thereby regulating the activity or other properties of that protein.Protein targeting（蛋白质分送）The process by which newly synthesized proteins are sorted and transported to their proper locations in the cell.Proteoglycan（蛋白聚糖）A hybrid macromolecule consisting of a heteropolysaccharidc joined to a polypeptide;the polysaccharide is the major component.3 3

Proto-oncogene（原癌基因）A cellular gene, usually encoding a regulatory protein, that can be converted into an oncogene by mutation.Proton acceptor（质子受体）An anionic compound capable of accepting a proton from a proton donor;that is, a base.Proton donor（质子供体）The donor of a proton in an acid-base reaction;that is, an acid.Proton-motive force（质子推动力）The electrochemical potential inherent in a transmcmbrane gradient of H'1' concentration;used in oxidative phosphorylation and photophosphorylation to drive ATF synthesis.Protoplasm（原生质）A general term referring to the entire contents of a living cell.Purine（嘌呤）A nitrogenous heterocyclic base found in nucleotides and nucleic acids;containing fused pyrimidine and imidazole rings.Puromycin（嘌呤霉素）An antibiotic that inhibits polypeptide synthesis by being incorporated into a growing polypeptide chain, causing its premature termination.Pyranose（吡喃糖）A simple sugar containing the six-membered pyran ring.Pyridine nucleotide（嘧啶核苷酸）A nucleotide coenzyme containing the pyridine derivative nicotinamide;NAD or NADP.Pyridoxal phosphate（磷酸吡哆醛）A coenzyme containing the vitamin pyridoxine(vitamin B(;);functions in reactions involving amino group transfer.Pyrimidine（嘧啶）A nitrogenous heterocyclic base found in nucleotides and nucleic acids.Pyrimidine dimer（嘧啶二聚体）A covalently joined dimer of two adjacent pyrimidine residues in DNA, induced by absorption of LIV light;most commonly derived from two adjacent thymines(a thymine dimer).Pyrophosphatase（焦磷酸酶）See inorganic pyrophosphatase.Q Quantum（量子）The ultimate unit of energy.Quaternary structure（四级结构）The three-dimensional structure of a multisubunit protein;particularly the manner in which the subunits fit together.R R group:(1)Formally, an abbreviation denoting any alkyi group.(2)Occasionally, used in a more general sense to denote virtually any organic substituent(the R groups of amino acids, for example).Racemic mixture(racemate)（外消旋化合物）An equimolar mixture of the u and L stereoisomers of an optically active compound.Radical（自由基）An atom or group of atoms possessing an unpaired electron;also called a free radical.Radioactive isotope（放射性同位素）An isotopic form of an element with an unstable nucleus that stabilizes itself by emitting ionizing radiation.4 3

Radioimmunoassay（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 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 NAD"".Redox reaction（氧还反应）: See oxidation-reduction reaction.Reducing agent(reductant)（还原剂）The electron donor in an oxidation-reduction reaction.Reducing end（还原端）The end of a polysaccharide having a terminal sugar with a free anomeric carbon;the terminal residue can act aa a reducing sugar.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（还原）Tlie gain of electrons by a compound or ion.Regulatory 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.5 3

Regulon（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（复性）Refolding of an unfolded(denatured)globular protein so as to restore native structure and protein function.Replication（复制）Synthesis of daughter nucleic acid molecules identical to the parental nucleic acids.Replication fork（复制叉）The Y-shaped structure generally found at the point where DNA is being synthesized.Replicative form（复制形式）Any of the full-length structural forms of a viral chromosome that serve as distinct replication intermediates.Replisome（复制体）The multiprotein complex that promotes DNA synthesis at the replication fork.Repressible enzyme（阻遏酶）In bacteria, an enzyme whose synthesis is inhibited when its reaction product is readily available to the cell.Repression:（阻遏）A decrease in the expression of a gene in response to a change in the activity of a regulatory protein.Represser（阻遏蛋白）The protein that binds to the regulatory sequence or operator for a gene, blocking its transcription.Residue（残基）A single unit within a polymer;for example, an amino acid within a polypeptide chain.The term reflects the fact that sugars, nucleotides, and amino acids lose a few atoms(generallytne elements of water)when incorporated in their respective polymers.Respiration（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 cells.Restriction endonucleases（限制性内切酶）Site-specific endodeoxyribonucleases causing cleavage of both strands of DNA at points within or near the specific site recognized by the enzyme;important tools in genetic engineering.Restriction fragment（限制片段）A segment of double-stranded UNA produced by the 6 3

action of a restriction endonuclease on a larger DNA.Restriction fragment length polymorphisms(RFLPs)（限制片段长度多态性）: Variations, among individuals in a population, in the length of certain restriction fragments within which certain genomic sequences occur.These variations result from rare sequence changes that create or destroy restriction sites in the genome.Retrovirus（反转录病毒）An RNA virus containing a reverse transcriptase.Reverse transcriptase（反转录酶）: An RNA-directed DNA polymerase in retroviruses;capable of making DNA complementary to an RNA.Ribonuclease（核糖核酸酶）A nuclease that.catalyzes the hydrolysis of certain internucleotide linkages of RNA.Ribonucleic acid:（核糖核酸）See RNA.Ribonucleotide（核糖核苷酸）A 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（核糖体）A supramolecular complex of rRNAs and proteins, approximately 18 to 22 imi in diameter;the site of protein synthesis.Ribozymes(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 phosphorylation and photophosphorylation.RNA(ribonucleic acid): A polyribunucleotide of a specific sequence linked by successive 3', 5'-phosphodiester bonds.RNA polymerase（RNA聚合酶）An enzyme that catalyzes the formation of RNA from ribonucleoside S'-triphosphates, using a strand of DNA or RNA as a template.RNA splicing（RNA拼接）Removal of introns and joining of exons in a primary transcript.rRNA: See ribosomal RNA.S S-adenosylmethionine(adoMet)（S-腺苷蛋氨酸或活化蛋氨酸）An enzymatic cofactor involved in methyl group transfers.Salvage pathway（补救途径）Synthesis of a biomolecule, such as a nucleotide, from intermediates in the degradative pathway for the biomolecule;a recycling pathway, as distinct from a de novo pathway.Saponification（皂化作用）Alkaline hydrolysis of triacylglycerols to yield fatty acids as soaps.Sarcomere（肌节）A functional and structural unit of the muscle contractile system.7 3

Satellite 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 fatty acid(饱合脂肪酸)A fatty acid containing a fully saturated alkyl chain.Second law of thermodynamics（热力学第二定律）The law stating that in any chemical or physical process, the entropy(熵)of the universe tends to increase.Second messenger（第二信使）An effector molecule synthesized within a cell in response to an external signal(first messenger)such as a hormone.Secondary metabolism（次生代谢）Pathways that lead to specialized products not found in every living cell.Secondary structure（二级结构）The residue-by-residue conformation of the backbone of a polymer.Sedimentation coefficient（沉降系数）A physical constant, specifying the rate of sedimentation of a particle in a centrifugal field under specified conditions.Selectins（选择蛋白）A large family of membrane proteins, lectins(凝集素)that bind oligosaccharides on other cells tightly and specifically, and serve to carry signals across the plasma membrane.SELEX;A method for rapid experimental identification of nucleic acid sequences(usually RNA)that have particular catalytic or ligand-binding properties.Serpentine receptors（蜿蜒受体）A large family of membrane receptor proteins with seven trans-membrane helical segments.These receptors often associate with G proteins to transduce an extracellular signal into a change in cellular metabolism.Shine-Dalgarno sequence（SD序列）A sequence in an mRNA required for binding prokaiyotic ribosomes.SH2 domain;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（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（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 hemoglobin.Sickle-cell trait（镰刀性状）A human condition recognized by the sickling of erythrocytes when exposed to low oxygen tension;occurs in individuals heterozygous for the allele responsible for sickle-cell anemia.Signal sequence（信号序列）An amino acid sequence, often at the amino terminus, that signals the cellular fate or destination of a newly synthesized protein.Signal transduction（信号传导）The process by which an extracellular signal(chemical, mechanical, or electrical)is amplified and converted to a cellular response.8 3

Silent mutation（沉默突变）A mutation in a gene that causes no detectable change in the biological characteristics of the gene product.Simple diffusion（简单扩散）The movement of solute molecules across a membrane to a region of lower concentration, unassisted by a protein transporter.Simple protein（简单蛋白）A protein yielding only amino acids on hydrolysis, Site-directed mutagenesis（定点突变）A set of methods used to create specific alterations in the sequence of a gene.Site-specific recombination（定点重组）A type of genetic recombination that occurs only at specific sequences.Size-exclusion chromatography（分子排阻层析）A procedure for the separation of a mixture of molecules on the basis of size, based on the capacity of porous polymers to exclude solutes above a certain size.Also called gel filtration(凝胶过滤).Small nuclear RNA(snRNA)（小核RNA）Any of several small RNA molecules in the nucleus;most have a role in the splicing reactions that remove introns from mRNA, tRNA, and rRNA molecules.Somatic cells(体细胞)All body cells except the germ-line cells（生殖细胞）.SOS response（应急反应）In bacteria, a coordinated induction of a variety of genes as a response to high levels of DNA damage.Southern blot（Southern印迹法）A DNA hybridization procedure in which one or more specific DNA fragments are detected in a larger population by means of hybridization to a complementary, labeled nucleic acid probe.Specific acid-base catalysis（狭义酸碱催化）Acid or base catalysis involving the constituents of water(hydroxide or hydronium ions).Specific activity（比活力）The number of micromoles(µmol)of a substrate transformed by an enzyme preparation per minute per milligram of protein at 25 °C;a measure of enzyme purity.Specific heat（比热）The amount of energy(in joules焦耳 or calories)needed to raise the temperature of 1 g of a pure substance by 1 ºC.Specific rotation（比旋光度）The rotation, in degrees, of the plane of plane-polarized light（平面偏振光）(D-line of sodium，钠的D线)by an optically active compound at 5 °C, with a specified concentration and light path.Specificity（特异性，专一性）The ability of an enzyme or receptor o discriminate among competing substrates or ligands, Sphingolipid（神经鞘磷脂）An amphipathic lipid with a sphingosine（鞘氨醇）backbone to which are attached a long-chain fatty acid and a polar alcohol.Spliceosome（拼接体）A complex of RNAs and proteins involved in the splicing of mRNAs in eukaryotic cells.Splicing(拼接)See gene splicing;RNA splicing.Standard free-energy change(ΔG΄°)（标准自由能变化）The free-energy change for 9 3

a reaction occurring under a set of standard conditions: temperature, 298 K;pressure, 1 atm or 101.3 kPa;and all solutes at 1 M concentration.ΔG΄° denotes the standard free-energy change at pH 7.0.Standard reduction potential(Έ’°): The electromotive 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（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(骨髓)that give rise to differentiated blood cells such as erythrocytes and lymphocytes.Stereoisomers（立体异构体）Compounds that have the same composition and the same order of atomic connections, but different molecular arrangements.Sterols（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 ends.Stop codons（终止密码）See termination codons.Stroma（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（底物）The specific compound acted upon by an enzyme.Substrate-level phosphorylation（底物水平磷酸化）Phoyphorylation of ADP or some other nucleoside 5'-diphosphate coupled to the dehydrogenation of an organic substrate;independent of the electron-transfer chain（电子传递链）.Suicide inhibitor（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（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（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（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, 0 Svedberg(S):(沉降系数)A unit of measure of the rate at which a particle sediments in a centrifugal field.Symbionts（共生体）Two or more organisms that are mutually interdependent;usually living in physical association.Symport（共转运）Cotransport of solutes across a membrane in the same direction.Synthases（合酶）Enzymes that.catalyze condensation reactions in which no nucleoside triphosphate is required as an energy source.Synthetases（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）.T Telomere（端粒）Specialized nucleic acid structure found at the ends of linear eukaryotic chromosomes.Template（模板）A macromolecular mold or pattern for the synthesis of an informational macromolecule.template strand（模板链）A strand of nucleic acid used by a polymerase as a template to synthesize a complementary strand.terminal transferase（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.termination codons（终止密码）UAA, UAG, and UGA;in protein synthesis, signal the termination of a polypeptide chain.Also known as stop codons.termination factors（终止因子）Protein factors of the cytosol required in releasing a completed polypeptide chain from a ribosome;also known as release factors.termination sequence（终止序列）A DNA sequence that appears at the end of a transcriptional unit and signals the end of transcription.Terpenes（萜类）Organic hydrocarbons or hydrocarbon derivatives constructed from recurring isoprene units.They produce some of the scents and tastes of plant products.tertiary structure（三级结构）The three-dimensional conformation of a polymer in its native folded state.Tetrahydrobiopterin（四氢生物喋呤）The reduced coenzyme form of biopterin（生物喋呤）.Tetrahydrofolate（四氢叶酸）The reduced, active coenzyme form of the vitamin folate(叶酸).thiamine pyrophosphate（焦磷酸硫胺素）The active coenzyme form of vitamin B1;involved in aldehyde transfer reactions.Thioester（硫酯）An ester of a carboxylic acid with a thiol or mercaptan.3' end:（3'端）The end of a nucleic acid that lacks a nucleotide bound at the 3' position of the terminal residue.1 4

Thromboxanes（凝血恶烷类）A class of molecules derived from arachidonate（花生四烯酸）and involved in platelet aggregation during blood clotting.Thylakoid（类囊体）Closed cisterna(囊), or disk, formed by the pigment-bearing internal membranes of chloroplasts.thymine dimer（胸腺嘧啶二聚体）See pyrimidine dimer.tissue culture（组织培养）Method by which cells derived from multicellular organisms are grown in liquid media.titration curve(滴定曲线)A plot of the pH versus the equivalents of base added during titration of an acid.Tocopherols（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（拓扑异构体）Different forms of a covalently closed, circular DNA molecule that differ only in their linking number.Topology（拓扑学）The study of the properties of an object that do not change under continuous deformations such as twisting or bending.Toxins（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 by an organism in only trace amounts.Transaminases（转氨酶）See aminotransferases（氨基转移酶）.Transamination（转氨作用）Enzymatic transfer of an amino group from an α-amino acid to an α-keto acid.Transcription（转录）The enzymatic process whereby the genetic information contained in one strand of DNA is used to specify a complementary sequence of bases in an mRNA chain.transcriptional control（转录控制）The regulation of a protein's synthesis by regulation of the formation of its mRNA.Transduction[（能量）转换、（信息）传导](1)Generally, the conversion of energy or information from one form to another.(2)The transfer of genetic information from one cell to another by means of a viral vector.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(转化)Introduction of an exogenous DNA into a cell, causing the cell to acquire a new phenotype.Transgenic（转基因的）Describing an organism that has genes from another organism incorporated within its genome as a result of recombinant DNA procedures.transition state（过渡态）An activated form of a molecule in which the molecule has 2 undergone a partial chemical reaction;the highest point on the reaction coordinate(反应进程图).Translation（翻译）The process in which the genetic information present in an mRNA molecule specifies the sequence of amino acids during protein synthesis.translational control（翻译控制）The regulation of a protein's synthesis by regulation of the rate of its translation on the ribosome.translational represser（翻译阻遏物）A represser that binds to an mRNA, blocking translation.Translocase（转运酶、移位酶）(1)An enzyme that catalyzes membrane transport.(2)An enzyme that causes a movement, such as the movement of a ribosome along an mRNA.Transpiration（蒸腾作用）Passage of water from the roots of a plant to the atmosphere via the vascular system（脉管系统）and the stomata（气孔）of the leaves.Transporters（转运体）Proteins that span a membrane and transport specific nutrients, metabolites, ions, or proteins across the membrane;sometimes called permeases.(透过酶)Transposition（转座）The movement of a gene or set of genes from one site in the genome to another.transposon(transposable element)（转座子）A segment of DNA that can move from one position in the genome to another.Triacylglycerol（三酰甘油）An ester of glycerol with three molecules of fatty acid;also called a triglyceride(三酰甘油酯)or neutral fat（中性酯）.tricarboxylic acid cycle（三羧酸循环）See citric acid cycle, triose（丙糖）A simple sugar with a backbone containing three carbon atoms.tRNA: See transfer RNA.tropic hormone(tropin)（促激素）A peptide hormone that stimulates a specific target gland to secrete its hormone;for example, thyrotropin(促甲状腺素)produced by the pituitary stimulates secretion of thyroxine（甲状腺素）by the thyroid（甲状腺）.turnover number（周转数）The number of times an enzyme molecule transforms a substrate molecule per unit time, under conditions giving maximal activity at substrate concentrations that are saturating.U Ubiquitin（泛蛋白）A small, highly conserved protein that targets an intracellular protein for degradation by proteasomes.Several ubiquitin molecules are covalently attached in tandem to a Lys residue in the target protein by a specific ubiquitinating enzyme.ultraviolet(UV)radiation（紫外辐射）Electromagnetic radiation in the region of 200 to 400 nm.uncompetitive inhibition（反竞争性抑制）The reversible inhibition pattern resulting 3 when an inhibitor molecule can bind to the enzyme-substrate complex but not to the free enzyme.uncoupling agent（解偶联剂）A substance that uncouples phosphorylation of ADP from electron transfer;for example, 2,4-dinitrophenol（2，4-二硝基苯酚）.Uniport（单向转运）A transport system that carries only one solute, as distinct from cotransport, unsaturated fatty acid（不饱合脂肪酸）A fatty acid containing one or more double bonds.urea cycle（尿素循环）A metabolic pathway in vertebrates, for the synthesis of urea from amino groups and carbon dioxide;occurs in the liver.Ureotelic（排尿素的）Excreting excess nitrogen in the form of urea.Uricotelic（排尿酸的）Excreting excess nitrogen in the form of urate(uric acid).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.Vectorial metabolism（方向性代谢）Metabolic transformations in which the location(not the chemical composition)of a substrate changes relative to a cellular membrane dividing two compartments.Transporters catalyze vectorial reactions, as do the proton pumps of oxidative and photophosphorylation.viral vector（病毒载体）A viral DNA altered so that it can act as a vector for recombinant DNA.Virion（病毒粒）A virus particle.Virus（病毒）A self-replicating, infectious, nucleic acid-protein complex that requires an intact host cell for its replication;its genome is either DNA or RNA.Vitamin（维生素）An organic substance required in small quantities in the diet of some species;generally functions as a component of a coenzyme.W wild type（野生型）The normal(unmutated)phenotype.Wobble（摆动、变偶）The relatively loose base pairing between the base at the 3' end of a codon and the complementary base at the 5' end of the anticodon.X x-ray crystallography（X-射线晶体学）The analysis of x-ray diffraction patterns of a crystalline compound, used to determine the molecule's three-dimensional structure.Z zinc finger(锌指)A specialized protein motif(基序)involved in DNA recognition by 4 4

some DNA-binding proteins, characterized by a single atom of zinc coordinated(配位)to four Lys residues or to two His and two Lys residues.Zwitterion（兼性离子）A dipolar ion, with spatially separated positive and negative charges.Zymogen（酶原）An inactive precursor of an enzyme;for example, pepsinogen(胃蛋白酶原), the precursor of pepsin（胃蛋白酶）.5 4

第二篇：生物化学双语教学单词

H1：genetic code

遗传密码

triplet code

三联体密码

termination codons / stop codons 终止密码子 initiation codon / start codon

起始密码子 degeneracy

简并性 universality

普遍性 point mutation

点突变 synonym

同义密码子

wobble base-pairing

摆动碱基配对 open reading frame

开放阅读框 H2:peptidyltRNA site

肽酰-tRNA位

aminoacyl-tRNA site

氨酰-tRNA位 polyribosome

多核糖体

N-formylmethionine

N-甲酰甲硫氨酸 aminoacyl-tRNA binding

氨酰-tRNA结合 peptide bond formation

肽键形成 translocation

转位 elongation factor（EF）延长因子 release factors（RF）释放因子 H3 monocistronic单顺反子

polycistronic多顺反子

cap binding protein

帽结合蛋白

H4 protein targeting

蛋白质导向

signal recognition particle(SRP)

信号识别颗粒 signal peptidase

信号肽酶 multiple membrane-spanning protein

多跨膜蛋白

integral membrane protein

内在膜蛋白 scavenger pathway

消除途径 chaperone

分子伴侣retention signal

滞留信号

mannose

甘露糖

endosome

内吞体 matrix

基质signal peptide

信号肽

H5 protein glycosylation

蛋白质糖基化

O-linked oligosaccharides

O联寡糖 N-linked oligosaccharides

N联寡糖 N-acetylgalactosamine(GalNAc)

N-乙酰半乳糖胺 monosaccharide units

单糖单位 pentasaccharide core structure

五糖核心结构 dolichol phosphate

长醇磷酸 mannose

甘露糖galactose半乳糖 sialic acid

唾液fucose岩藻糖

I1 genomics

基因组学 transcriptomics转录组学

proteomics

蛋白质组学

metabolomics

代谢组学 reverse genetics

反向遗传学 RNA interference

RNA干扰 transgenic organism

转基因生物

I2 restriction enzyme

限制性核酸内切酶 staggered cut

交错切割 cohesive end

粘性末端 blunt end

平端 co-inherited

共遗传 closely linked

紧密连锁 autoradiography

放射自显影

restriction fragment length polymorphisms(RFLP)限制性片段长度多态性 I3denaturation 变性melting temperature 解链温度 renaturation复性in situ hybridization 原位杂交 annealing

退火 hybridization

杂交

probe

探针

blotting

印迹 hybrid

杂种

stringency

严紧性 radioactive 放射性 nonradioactive

非放射性

I4 clone

克隆 bacteriophage

噬菌体 plasmid

质粒recombinant plasmid 重组质粒 transfection 转染vector

载体 screening

筛选 DNA library

DNA文库

lawn

菌苔 plague

噬菌斑 nitrocellulose membrane 硝酸纤维素膜 colony lift

菌落转移

I5 DNA sequencing

DNA 测序 chemical method

化学法 chain termination method

链终止法

oligonucleotide

寡核苷酸 dideoxynucleotide双脱氧核苷酸

I6 polymerase chain reaction

聚合酶链反应

denaturation

变性 annealing

退火 elongation

延伸 quantity PCR

定量PCR

J1 monosaccharide 单糖 disaccharide

双糖 aldose

醛糖ketose酮糖

pentose

戊糖 hexose

己糖 glucose

葡萄糖galactose半乳糖

mannose

甘露糖 fructose

果糖 reducing sugar 还原糖glycosidic bond

糖苷键 epimer差向异构体sugar derivative糖衍生物 structure isomer

结构异构体 stereoisomer

立体异构体

J2 polysaccharide

多糖J3 glycolysis

糖酵解

glycogen

糖原

hexokinase

己糖激酶 starch

淀粉aldolase醛缩酶 oligosaccharide

寡糖mutase变位酶

N-linked oligosaccharide

N-联寡糖enolase烯醇化酶 O-linked oligosaccharide

O-联寡糖 glycoprotein

糖蛋白 glycolipid

糖脂

J3phosphoglucoisomerase

磷酸葡萄糖异构酶 phosphofructokinase

磷酸果糖激酶 triose phosphate isomerase磷酸丙糖异构酶 phosphoenolpyruvate磷酸烯醇式丙酮酸

substrate-level phosphorylation 底物水平磷酸化

J4 gluconeogenesis

糖异生

oxaloacetate

草酰乙酸 carboxylation

羧化作用carboxylase

羧化酶 carboxykinase羧激酶citrate

柠檬酸

anaplerotic effect

回补作用malate

苹果酸 phosphoenolpyruvate（PEP）磷酸烯醇式丙酮酸 phosphoglucoisomerase磷酸葡萄糖异构酶

J5pentose phosphate pathway

磷酸戊糖途径 ribose 5-phosphate

核糖 5-磷酸

glucose 6-phosphate dehydrogenase葡萄糖6-磷酸脱氢酶 transketolase转酮酶transaldolase转醛酶

J6glycogen

糖原glycogen synthase

糖原合酶

glycogen phosphorylase糖原磷酸化酶glycogen-debranching enzyme 糖原脱支酶 nonreducing end

非还原末端pyrophosphorylase焦磷酸化酶 phosphoglucomutase磷酸葡萄糖变位酶 glycogenin生糖原蛋白

J7 epinephrine

肾上腺素 glucagon

胰高血糖素 blood sugar

血糖 adenylatecyclase腺苷酸环化酶

protein kinase A

蛋白激酶A calcium

钙

K1 saturated fatty acids

饱和脂肪酸 unsaturated fatty acids

不饱和脂肪酸 palmitate软脂酸

stearate

硬脂酸 linoleate亚油酸 linolenate亚麻酸

arachidonate花生四烯酸

prostaglandin

前列腺素

K2 acyl-CoA

脂酰 CoA

carnitine肉毒碱 translocase转位酶 thiolysis硫解

hydration

水合，加水 ketone bodies 酮体

acetoacetate

乙酰乙酸 acetone

丙酮 3-hydroxybutyrate

-羟丁酸 K3 acyl carrier protein(ACP)

酰基载体蛋白 carboxylation

羧化

malonyl CoA

丙二酸单酰CoA acetyl CoA carboxylase

乙酰CoA羧化酶 phosphopantetheine磷酸泛酰巯基乙醇 condensation

缩合 dehydration

脱水 thioesterase硫脂酶 desaturase去饱和酶

K4triacylglycerol

三酰甘油（脂肪）glycerol

甘油

free fatty acid

自由脂肪酸 diacylglycerol二酰甘油

lipase

脂酶 bile salt

胆汁盐

hormone-sensitive lipase

激素敏感脂酶 K5cholesterol

胆固醇 steroid

类固醇 bile salt

胆汁盐 HMG CoA reductase羟甲戊二酰CoA还原酶 ricket佝偻病

osteomalacia软骨症

第三篇：生物化学双语教学的探讨

生物化学双语教学的探讨

【摘 要】“双语教学”是21世纪全球教育改革的重要内容之一，在医学院校推行生物化学双语教学具有多方面的现实意义。本文从教师、学生以及教学方法三个方面阐述了医学生物化学双语教学中存在的问题，并就解决办法提出了建议。

【关键词】双语教学 医学院校 生物化学

【中图分类号】G642.0 【文献标识码】A 【文章编号】1674－4810（2011）24－0013－02

“双语教学”是21世纪全球教育改革的重要内容之一。从目前的临床医学和科研工作来看，语言不足已成为国内学者对外交流的障碍，由于专业英语语言能力不足，许多优秀的科研成果得不到国外同行的认可和共享；从教学角度看，国外医学教材如果经过翻译再在教学中使用，会造成学生获取新知识的时间远远落后于知识更新的周期。基于这些问题的存在，实施双语教学可作为解决此矛盾的一条重要途径。

作为新兴的医学本科院校，我院一直致力于加强学校的本科教学工作，提高教学质量，并根据自身发展需求以及新时期对学生能力素质的要求，不断摸索好的教育教学改革方法，其中重要的一项便是实行双语教学。下面就已开设的生物化学双语教学中出现的问题及解决方法进行探讨。

一 双语教学的定义

所谓双语教学，是指以母语和一门外语两种语言作为教学用语的教学模式。各国各地区因母语不同而有所区别，我国双语教学的具体定位是汉语和英语，并在此基础上兼顾其他语种。2002年，教育部高教司在下发的《普通高等学校本科教学水平评估方案（试行）》中，第一次将双语教学的课程定义为采用外文教材并用外语授课的课时占该课程总课时的50%以上。

目前，双语教学的模式主要有以下三种类型：（1）沉浸式双语教学。这种类型的教学模式要求完全用外语进行教学，母语不用于教学中，使学生完全沉浸于弱势语言中。（2）过渡式双语教学。这种类型的教学模式要求在学生刚进入学校时，部分或全部科目使用母语教学，一段时间后，逐步转变为全部科目使用外语教学。其最终目的仍然是向沉浸式的教学模式过渡。（3）保留式双语教学。这种类型要求在学生刚进入学校时使用母语教学，以后逐步部分科目使用外语教学，部分科目仍用母语教学。由于语言环境的限制，目前国内大多数院校仍采取保留式双语教学，我院也不例外。

二 我院生物化学教学推行双语教学的必要性

1．医学事业的不断发展迫切需要双语复合型人才

高等医学教育是国际公认的通用性、可比性较强的专业教育领域，对医学工作者的素质和能力的要求基本一致，因而高等医学教育也存在很多共通之处。面对公众健康问题和越来越严峻的全球疫病防疫形势，人们逐渐意识到跨越国界的国际医疗合作的重要性，对医疗从业人员的知识、能力结构提出了新的要求。医学作为专业性极强的学科，其相关工作是一般外语人才无法替代的，因此，社会迫切需要医学院校培养一大批既懂得专业知识又具有相当外语水平的复合型医学人才。

2．生物化学课程的特点要求在教学过程中使用双语

在世界范围内对医学生物化学进行比较后发现，使用英语进行生物化学的科学研究、生产活动、教学及教材编写等都处于领先地位，这对我国在生物化学领域中的发展有一定的借鉴和指导意义。原版教材的引入也可节省翻译所消耗的时间及减少内容方面的损失，使学生及时地了解到最新的研究进展，跟上时代发展的脚步。

同时，英语国家在医学生物化学领域的学科发展、学术交流及科研方法等方面处于主流地位，可作为生物化学学习、进修及培训的理想国家，这也使得用英语开展生物化学双语教学具有现实意义。

三 双语教学过程中存在的问题及解决方法

1．教师方面

双语教学是提高教学效果、培养高素质人才的有效途径，而保证这一目标实现的基本条件是承担双语教学教师的能力。目前在我国一些医学院校中，能使用英语上课的教师非常少，特别是对于生物化学这样一门复杂难懂的学科，要让任课教师用英语清楚地说明四大营养物质代谢的过程以及调控机制等，确实有很大难度。双语教学对教师的要求非常之高，不仅专业知识要精深，还必须能用熟练、准确的英语来表达专业知识以及分析专业术语和词汇。既使有些老师在课前做了细致的准备，在课堂上能够把课件上的内容流利地讲述出来，但遇到与同学互动的环节，回答学生提问时，由于受到语言的限制，很难用英语应对突发事件。聘请外教，也必须要求懂得汉语，这样才有利于理解学生在学习中可能出现的困难，并及时解决。

我院是一所新兴的本科院校，青年教师所占比例较大，真正能做到双语教学的教师少之又少。为了解决这一问题，学校一方面利用现有师资中听、说、读、写能力较好的教师定期进行英语培训，提高英语水平；另一方面充分利用留学者及国外来访者，多与他们进行交流，了解国际医学领域一些最新的知识和技术，为进行双语教学方面做好充分的准备。

2．学生方面

学生的外语水平也是决定双语教学能否顺利进行的一个重要因素。生物化学双语教学不仅要求教师有良好的英语能力，也要求学生有一定的英语基础，除了公共英语要达到CET-4以上水平外，还应掌握一定量的专业英语词汇。但是由于本院学生的英语水平参差不齐，师生之间的课堂互动不如单语教学，教学效果低于预期，不仅造成教师教学的成就感降低，还使得学生在学习过程中的思维主动性、连贯性、创造性被阻断，影响对本门课程的学习兴趣。因此，学生的接受能力和教师的授课能力同等重要，只有老师和学生都具有一定的英语能力，双语教学才能做得更好。

学生课前预习对提高双语教学课堂效率非常重要。生物化学专业知识本来就晦涩难懂，若要求学生用英语思维，并在短暂的课堂时间内完全理解老师用英语传授的专业知识，难度可想而知。单纯也将传统被动式的教学模式应用于双语教学课堂，势必收获甚微，因此学生必须采取积极主动的态度融入双语教学中去，教师也可在课后提出几个与下节课内容相关的问题，让学生在寻找答案的过程中做好预习准备。

3．教学方法

传统教学中常用的讲授法、演示法、启发式等不能适应双语教学课堂。在教学方法上，我们应着眼于现代化，构建集课堂教学、多媒体教学、网络教学为一体的多维立体教学平台，充分利用计算机辅助教学手段，制作双语CAI课件，使之具有双语性特点，做到关键词、主要内容有英汉对照，并有标准英文发音。此外，还可配上适量图片或小段英文视频、录像、实物演示等，力争使课堂气氛活跃，增强学生的积极性和参与性，从而达到预期的教学目的。

参考文献

［1］何兴祥、刘伟、沈清燕等.医学双语教学探析［J］．中华医学教育杂志，2004.（3）：32～33

［2］李萍、夏新娟.大学双语教学探讨［J］．重庆交通学院学报（社科版），2002.2（3）：77

［3］李俊伟.高等院校专业课程开展双语教学的若干问题分析［J］．中国高等医学教育，2004.3：14～15

［4］初国良、汪华侨、彭映基等．推进解剖学双语教学 培养高素质医学人才［J］．解剖学研究，2002.4：313～314

［5］陈晶瑛.高校开展“双语教学”的现状、问题与对策［J］．经济师，2005.1：119～120

［6］熊静、黎宇宁.双语教学实践初探［J］．咸宁学院学报，2005.4：149～150

〔责任编辑：王以富〕

第四篇：浅谈高等院校双语教学在生物化学课程中的应用 OK最后

浅谈高等院校双语教学在生物化学课程中的应用

摘要: 本文就双语教学在生物化学课程中的应用,从介绍什么是双语教学,到探索生物化学课程的双语教学的课程体系与评价体系。探讨高等院校双语教学在生物化学课程中的应用。关键词:双语教学 生物化学课程 双语教学模式探索

21世纪已经到来，以加强外语和计算机为新世纪人才特征的教育教学、课程改革方兴未艾，“大德育”、“探究型学习”、“双语教学”等新概念成为“热门主题”，成为推进“素质教育”的又一着陆点。其中“双语教学”是最引人注目的视点。1 双语教学

双语教学：双语教学就是将母语以外的另外一种语言直接应用于语言学科以外的其他各种学科的教学，使第二语言的学习与各学科知识的获取同步进行。

在中国，双语教学是指除汉语外，用一门外语作为课堂主要用语进行学科教学，目前绝大部分是用英语。它要求用正确流利的英语进行知识的讲解，但不绝对排除汉语，避免由于语言滞后造成学生的思维障碍；教师应利用非语言行为，直观、形象地提示和帮助学生理解教学内容，以降低学生在英语理解上的难度。中国不象新加坡、加拿大、印度是一个双语国家，语言环境并不是中外并重，所以中国的双语教学环境决定了它的目的性，属于“外语”教学

3范畴，而不是“第二语言”的教学范畴。中国的双语教学只能是上述界定中的“保持型双语教学”。

生物化学双语教学是指教师贯彻双语课优势互补、相互促进的教学思想，即，在生物化学教学中同时使用两种语言—— 母语及第二外语来组织、安排、实施教学活动，使生物化学知识与专业外语运用产生有机融合，并在这种全新教学模式所形成的特殊氛围中，让学生在学习生物化学知识的同时，高效率地加强专业外语的学习与掌握，使学生初步具备直接阅读生物化学及相关专业的外文版教材、外文期刊等资料的能力；而且可促使学生多渠道了解国外本专业最新的学术动态和各种学术观点，扩大学生的专业视野；同时使学生利用最新的外文资料进行小型的学术研究。

双语教学最初源于国外，它在国外的发展已有较长的历史，在理论与实践两个方面都有长足的进步。而在我国，双语教学发展的历史较短，目前的高校所进行的双语教学改革多数尚处于实践摸索阶段，国外的经验和实践只能作为参考，并不能照搬照抄。即使国内高校实施双语教学也取得了不少成绩，但由于校情不同，面临的学生对象不一样，因此也不能照搬他们的做法，且国内双语教学提出的有关双语教学的观点过于宏观、针对性不强，因此也不便完全采纳，本论文旨在广泛阅读文献的基础上和针对本省高职院校的实际情况，特别是本校的实际情况，以生物化学课程为突破口，探索适合综合高职院校生物化学课程双语教学的模式，以期对生物化学双语教学的实施起到实质性的指导和推动作用。2.进一步深化生物化学课程改革，提高学生和教师的专业英语技能。①研究教材：学习生物化学理论课教学大纲，统一教学章节的重点和难点，加强课题组间的交流与互助，一起面对教材上的难点，逐个分解难点。②写出设计详细的讲稿：在双语教学的初始阶段，双语讲稿需要十分全面、系统和详尽。课堂上所有教学内容，包括每一个问题，每一个段落，每一个细节都要在讲稿中。特别是问题之间、段落之间的过渡性语言，要用醒目的英语写在教案中。③精心设计每一个教学问题，这些问题即要反映专业知识又要与我们周围生活实际有关联。④制作课件时尽量将表达语句较长的句子分解成几个短句，并通过网络收集尽量多的相关章节图片，使内容更形象生动。⑤ 强调预习：要求学生在上每一章之前都要将该章中的专业词汇记下来，并查其含义和发音，由学委检查同学预习情况，记入平时成绩中。我们认真分析不同章节的内容特点与难易程度，探索适合每一章节的教学模式。3.1 问题式教学的探索

如在讲信息分子代谢这一章时，我们给学生留了8个问题，要求学生回去后针对这些问题，认真阅读教材，结合网络资源，完成下面的问题。我们并不是要求学生给出完全正确的答案，而是督促学生带着问题用心阅读教材，并向学生推荐一些有关信息分子的英文学习网站

3.2 讨论式教学的探索

“讨论式”课堂教学是在教师的引导下，学生以小组或全班为单位，通过讨论或辩论，发现问题、获得知识、培养能力的一种课堂教学形式。

4.深入研究，不断反思，构建生物化学双语教学的课程体系与评价体系。4.1.课程体系的构建

生物化学是高职生物技术专业的一门专业基础课，理论课课时原先仅有42个学时，如何在有限的时间内传授生物化学的基本理论，需要根据专业培养的计划特点，优化理论教学体系，调整理论教学内容，本着少而精的原则，合理取舍精减教学内容。同时又保证本课程的重点核心内容得到讲解。这样安排虽然能在较短的时间内完成教学内容，但教学效果有待提高。所以，重新构建新的生物化学课程体系。首先，要遵循循序渐进性。

从语言习得的衔接角度来看考虑，专业双语课程的开设在大学的第三学期（包括第三学期）之后比较合理，因为前三个学期始终贯穿着公共基础课大学英语的学习，为英语教学在双语教学的实际应用，这样英语就不只是学习的目标,它更是达到其他专业知识学习目的和手段，使学生真正学会把英语当成一个帮助自己获取各种知识的实用工具，更好地促进自己在专业领域的研究和实践活动，这才是英语学习的真正意义所在；而专业英语的学习为开启双语教学做了必要的铺垫，使学生能够阅读、理解、翻译和应用专业文献，对自己本专业的知识有一个基本的了解。另一方面，双语课的开始,也可以较好地起到英语教学的过渡和衔接作用，从而有效地保证学生完成从英语学习阶段到英语使用阶段的过渡。大四上半学期，通过毕业论文设计，要求学生通过互联网查阅中英文资料，完成毕业论文的前半部分内容（课题研究的意义，国内外研究的现状），并翻译论文的摘要，这是对学生双语教学的一次锻炼和小型检阅。从专业知识的掌握难易程度上考虑，生物化学涉及的专业知识要比分子生物学和生物技术专业知识较易，因此适合作为专业双语教学初始课程。

其次，遵循专业知识的系统完整性。

现在开设的双语课程，绝大多数比较孤立，因人设课较多。在实际教学中，生物化学与多门课程之间内容上有着密切的联系，结果导致：一方面学生因知识衔接不上而造成理解上的困难，另一方面因双语课程的孤立性，使所学的专业双语知识在其它课程中得不到应用，形成不了双语教学的氛围，致使学生的学习效率大大降低。因此，在选择和安排双语教学课程时，要注意整个课程体系的全方位建设，注意各门课程之间在知识内容方面的衔接性，决不能把双语教学课程单单作为一门孤立的课程来进行传授，不能以降低整个学科教学质量为代价来换取一门孤立的双语教学课程质量的提高。4.2.双语教学质量评价体系的构建

双语教学的评价，是双语教学过程中必不可少的环节，它是检验双语教学效果、检验双语教师的业务水平、工作态度、教学方法、学生学习情况的必要手段，是检验教学质量高低的重要措施。

以双语教学的形式和手段，培养学生的阅读能力、计算能力、写作能力、电脑信息处理运

用能力、现代交际能力和其它必要的生存常识，已经成为当今学生和家长们所追求的热点2。参考文献

1.孔璐 余和芬 潘颖 孙林 于培兰 马惠苹 贺旭, 医学生物化学与分子生物学实行双语教学的思考,科技信息,2008 2.王洋洋, 双语教学的理论与实践研究, 四川文理学院学报2006

第五篇：生物化学双语教学的尝试与问题分析

生物化学双语教学的尝试与问题分析

南方医科大学基因工程研究所

曹东林 李凌 彭翼飞

为了适应新时代的要求,贯彻教育部关于加强高等院校本科教学工作提高教学质量的若干意见,近年来医学院校开始在医学教育中推行双语教学,以培养具有较强国际竞争力的高级医学人才。生物化学是我校双语教学课程之一,在教学过程中我们积累了一定的经验,同时也发现了许多的不足和问题。1.双语教学的内涵及目的

双语教学(Bilingual Teaching)是指除汉语外,用一门外语多为英语作为课堂主要用语进行学科的教学，它不仅仅是指学生听老师用英语上课,更强调的是师生之间用英语进行课堂教学的交流和互动,逐渐培养学生用外语思考，解决问题的能力。即双语教学的最终目标是使学生能同时使用母语和外语进行思维,根据实际需要在这两种语言间进行自由切换。它要求用准确、流利的外语进行知识的讲解,但不绝对排除汉语,以避免由于语言障碍造成学生对专业知识的理解困难而影响教学效果。

2.生物化学双语教学的应用体会 2.1 强调医学双语教学的必要性和可行性

开课前花一点时间来调查和开一个较短时间的动员会，强调医学双语教学的必要性和可行性，对激发学生学习兴趣和建立信心大有帮助。世界上权威的医学期刊、书籍及计算机检索数据库基本上都以英语出版,真正意义上的国际会议,多以英语进行交流，要想紧跟世界医学发展的步伐，不断提出科研的新思路，抑或在国际权威医学期刊上投一篇文章都得熟练运用英语及一些语言技巧来表达你的思想才有可能录用。医学院校实行双语教学是培养高级医学人才的需要，也是我国生命科学尽快与国际接轨的需要。随着我国对英语教学越来越重视,教学质量逐年提高,医学院多数学生都具有扎实的英语基础、较高的英语读写能力,大学英语四、六级的通过率已较高，为医学双语教学的实施提供了有利条件。在医学教育中实施双语教学,不断给医学生予英语语言刺激,让学生逐渐习惯用英语思维,从而提高学生的国际交流能力。2.2注重因材施教，强调教学互动性

开课前与同学进行充分的交流,获取了详细的反馈信息,制定一个合适的中英文讲授比例,做到因材施教。授课时要注意时间效率，随时注意学生的反应,询问学生对本部分讲解是否能较好理解,以便了解学生的吸收程度,并及时调整上课的语速和进度。让学生及时对难懂或不懂之处提问,以决定是否复述重点内容,必要时重点或难点内容可用中文复讲解，但母语的使用要控制在最低限度，而对于涉及重点或难点内容的有关词汇及英美人的习惯用法得反复讲解。亦可结合本校的教学目标和学生外语实际水平,编写双语教学讲义和双语教学大纲,并提前发给学生预习。预习时将教材中涉及较难的医学词汇单独标识出来,并加以中文释义,提前扩大学生医学外语词汇量。还要专门组织老师编写了双语教学考试命题办法和考核办法、英语试卷库和答题示范等。双语教学应强调师生间的互动,主张教学环境、教学资源等全方位的第二语言的交互,只有当英语在医学知识教学过程中得到广泛运用和交流,两种不同的语言能在学生的思维与交流中自由熟练切换的时候,我们才可以认为双语教学获得了成功。2.3 多样的教学手段与灵活的考核相结合

为了激发同学们的兴趣，我们对教学手段和考核的方式都进行了不少的尝试。首先，选择的课件均是自己考虑成熟制作的多媒体课件,也有借鉴或直接选用国外已经出版的英语医学教学课件，对其中的优缺点了然于心。其次，利用多样化的教学手段如图片、多媒体、录像等,尽量把生物化学中的抽象概念具体化、直观化、简单化,以帮助学生更好地理解生物化学中的专业知识。再次，充分利用网络技术，尤其是我校自己的局域网,通过FTP或文件共享等方式做到多媒体课件上网,方便学生随时查询,递交作业。另外还开设教学论坛,公开自己的email地址，方便学生提出问题和解决问题；至于考核方式也进行必要的改革，合理的考核模式是教学的指挥棒,所以在教学中应根据双语教学的特点,不再单纯采用传统的试卷考核,而是采用综合多次课业成绩、课堂的口语问答及课终闭卷考试来进行，避免“一卷定终身”。3.生物化学双语教学的存在的问题 3.1 师资水平直接影响了双语教学的推广

教师的外语水平是决定双语教学质量的关键因素。双语教学要求师资水平很高,不仅要懂得专业知识,还要掌握外文。又由于医学专业的特殊性,其专业词汇相对较长较多,记忆难度较大，对于大多数专业课老师来说,生活在汉语环境里,虽然接触外语较多,也有一定的听说读写能力,但思维方式仍然是汉语思维,在教学中很难进行中英文自由转换。目前,大部分老师只不过是采用专业英语名词代替专业中文名词,课堂教学时对外文教材中的内容进行翻译、讲解为主。3.2 学生的外语水平和语言环境也是影响教学效果不可忽视的因素

学生英语基础较差，水平参差不齐。尽管医学院校的大学生学了近十年的英语,掌握了相当量的公共英语和专业英语词汇, 四、六级通过率不断上升，也系统地学习了语法知识,但仍存在听不懂,看得慢现象,更无法用外语直接进行交流、对话。另外性格上总是羞于表达自己，课堂上显得沉闷了些。我们生活在一个几乎完全被汉语包围的语言环境里,学了多年英语,仍然是哑巴英语,这在中国是普遍存在的问题，这很值得深思，更应该引起教育主管部门及学校领导的重视，创造和提供良好的学习外语环境和设备。

3.3 缺乏优秀的双语教学教材,疏于教学信息的管理

双语教学最好使用外文原版的教材,然而,目前国际上通用的教材价格昂贵,一般院校很难承受高额的教材费用。故不同教师使用的教材有的是国外原版教材,有的是节选外文教材,也有的是教师自编的讲义,版本和内容不统一,教学随意性较大。另外,教材难易程度的不同也影响了双语教学的实际效果；而对教学信息缺乏有效整理是很多院校存在的普遍问题。对双语教学的课程实施全面跟踪,以便及时发现和解决双语教学过程中的问题,认真听取学生意见和建议,重视学生信息反馈,完善信息网络，这对于稳步推进双语课程建设是非常重要的一环。然而，遗憾的是很多时候仅仅是草草收场，敷衍了事，满足于完成教学任务。总之,双语教学在我国高校尚处于试验和起步阶段,我们缺乏成熟的双语教学理论和教学经验,需要在教学中不断地摸索和总结。在教学中出现许多问题和不足是难免的,相信不久的将来,双语教学将步入正轨,逐渐形成自己特有的教学模式。

参考文献：

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