马林 生物化学练习题

1、第一章 核酸名词解释(英语解释)单核苷酸(mononucleotide) 单核苷酸，一种化合物，一类由嘌呤碱或嘧啶碱、核糖或脱氧核糖以及磷酸三种物质组成的化合物。又称核甙酸。戊糖与有机碱合成核苷,核苷与磷酸合成核苷酸,4种核苷酸组成核酸。核苷酸主要参与构成核酸，许多单核苷酸也具有多种重要的生物学功能，如与能量代谢有关的三磷酸腺苷（ATP）、脱氢辅酶等。Nucleotides are organic molecules that form the basic building blocks of nucleic acids, such as DNA and RNA. A nucleotide i

2、s composed of a nucleobase, a pentose(ribose or deoxyribose) and at least one phosphate group.Nucleotides serve to carry packets of energy within the cell (ATP). In the form of thenucleoside triphosphates (ATP, GTP, CTP and UTP), nucleotides play central roles inmetabolism.1 In addition, nucleotides

3、 participate in cell signaling (cGMP and cAMP), and are incorporated into important cofactors of enzymatic reactions (e.g. coenzyme A, FAD, FMN, NAD, and NADP+).3, 5-磷酸二酯键（phosphodiester bonds）是核酸分子中的磷酸基团的磷原子与另外两个五碳糖分子的碳原子之间形成的共价键。这种形式的键结于DNA及RNA分子中负责将分别位于两个核糖上的3号碳与5号碳连结起来。A phosphodiester bond is a

4、 group of strong covalent bonds between a phosphate group and two 5-carbon ring carbohydrates (pentoses) over two esterbonds. In DNA and RNA, the phosphodiester bond is the linkage between the 3' carbon atom of one sugar molecule and the 5' carbon atom of another.碱基互补规律(complementary base pa

5、iring) 在DNA分子结构中，由于碱基之间的氢键具有固定的数目和DNA两条链之间的距离保持不变，使得碱基配对必须遵循一定的规律，这就是Adenine（A，腺嘌呤）一定与Thymine（T，胸腺嘧啶）配对，Guanine（G，鸟嘌呤）一定与Cytosine（C，胞嘧啶）配对，反之亦然。碱基间的这种一一对应的关系叫做碱基互补配对原则。Chargaff's rules state that DNA from any cell of all organisms should have a 1:1 ratio (base Pair Rule) of pyrimidine and purine

6、 bases and, more specifically, that the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine. This pattern is found in both strands of the DNA. They were discovered by Austrian chemist Erwin Chargaff.核酸的变性与复性（denaturation、renaturation）  (1).当呈双螺旋结构的DNA 

7、溶液缓慢加热时，其中的氢键便断开，双链DNA 便脱解为单链，这叫做核酸的“溶解”或变性 .(2) 在适宜 的温度下，分散开的两条DNA 链可以完全重新结合成和原来一样的双股螺旋。这个DNA 螺旋的重组过程称为“复性”。退火（annealing） 即DNA由单链复性、变成双链组织的进程。加热使DNA双螺旋解开，在一定的条件下，两条互补的单链依靠彼此的碱基配对重新形成双链DNA的过程，亦即复性过程。热变性的DNA单链在缓慢冷却过程中可以达到很好的退火。Annealing, in genetics, means for complement

8、ary sequences of single-stranded DNA or RNA to pair by hydrogen bonds to form a double-stranded polynucleotide. The term is often used to describe the binding of a DNA probe, or the binding of a primer to a DNA strand during a polymerase chain reaction. The term is also often used to describe the re

9、formation (renaturation) of complementary strands that were separated by heat (thermally denatured).增色效应（hyper chromic effect） DNA变性后，DNA 溶液的紫外吸收作用增强的效应。双链DNA 分子中碱基间电子的相互作用是紫外吸收的结构基础，但双螺旋结构有序堆积的碱基又“束缚”了这种作用。变性DNA的双链解开，碱基中电子的相互作用更有利于紫外吸收，故而产生增色效应。The hyperchromic effect is the striking increase in ab

10、sorbance of DNA upon denaturation. The hydrogen bond of double stranded DNA limits the resonance of the aromatic ring so the absorbance of the sample is limited as well. When the DNA double helix separates into two single strands,the base-base interaction will be reduced, increasing the UV absorbanc

11、e of DNA solution because many bases are in free form and do not form hydrogen bonds with complementary bases.发夹结构（hairpin structure）多核苷酸链中由茎区(双链区、螺旋区)和环区(单链区)组成的类似于“发夹”状的结构。常出现在RNA的二级结构中。RNA是单链线形分子，只有局部区域为双链结构。这些结构是由于RNA单链分子通过自身回折使得互补的碱基对相遇，形成氢键结合而成的，称为发夹结构。Stem-loop intramolecular base pairing is

12、a pattern that can occur in single-stranded DNA or, more commonly, in RNA. The structure is also known as a hairpin or hairpin loop. It occurs when two regions of the same strand, usually complementary innucleotide sequence when read in opposite directions, base-pair to form a double helix that ends

13、 in an unpaired loop. The resulting structure is a key building block of many RNA secondary structures.DNA的熔解温度（melting temperature Tm） 是把DNA双螺旋结构失去一半时的温度称为该DNA的熔解温度,它受好多不同因素的影响.DNA的熔解也就是它的变性了.The melting temperature (Tm) is defined as the temperature at which half of the DNA strands are in the rand

14、om coil or single-stranded (ssDNA) state. Tm depends on the length of the DNA molecule and its specific nucleotide sequence. DNA, when in a state where its two strands are dissociated (i.e., the dsDNA molecule exists as two independent strands), is referred to as having been denatured by the high te

15、mperature.分子杂交（molecular hybridization）分子杂交（molecularhybridization）确定单链核酸碱基序列的技术。其基本原理是待测单链核酸与已知序列的单链核酸（叫做探针）间通过碱基配对形成可检出的双螺旋片段。这种技术可在DNA与DNA，RNA与RNA，或DNA与RNA之间进行，形成DNA-DNA，RNA-RNA或RNA-DNA等不同类型的杂交分子。A molecular probe is a group of atoms or molecules used in molecular biology or chemistry to study th

16、e properties of other molecules or structures. If some measurable property of the molecular probe used changes when it interacts with the analyte (such as a change in absorbance), the interactions between the probe and the analyte can be studied. This makes it possible to indirectly study the proper

17、ties of compounds and structures which may be hard to study directly. The choice of molecular probe will depend on which compound or structure is being studied as well as on what property is of interest. Radioactive DNA or RNA sequences are used in molecular genetics to detect the presence of a comp

18、lementary sequence by molecularhybridization1.环化核苷酸(cyclic nucleotide) 作为细胞功能的调节分子和信号分子，重要的有3，5环线苷酸和3，5环鸟苷酸，这两种环化核苷是动物激素作用于靶细胞后产生的胞内信使，有传递和放大激素信号的作用，有被称为“第二信使”A cyclic nucleotide (cNMP) is a single phosphate nucleotide with a cyclic bond arrangement between the sugar and phosphate groups. Like other

19、 nucleotides, cyclic nucleotides are composed of three functional groups: a sugar, a nitrogenous base, and a single phosphate group. As can be seen in the cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) images, the 'cyclic' portion consists of two bonds betwee

20、n the phosphate group and the 3' and 5' hydroxyl groups of the sugar, very often a ribose.Their biological significance includes a broad range of protein-ligand interactions. They have been identified as secondary messengers in both hormoneand ion-channel signalling in eukaryotic cells, as w

21、ell as allosteric effector compounds of DNA binding proteins in prokaryotic cells. cAMP and cGMP are currently the most well documented cyclic nucleotides, however there is evidence that cCMP (cytosine) is also involved in eukaryotic cellular messaging. The role of cyclic uridine monophosphate (cUMP

22、) is even less well known.Discovery of cyclic nucleotides has contributed greatly to the understanding of kinase and phosphatase mechanisms, as well as protein regulation in general. Although more than 50 years have passed since their initial discovery, interest in cyclic nucleotides and their bioch

23、emical and physiological significance continues.DNA复性（退火）一般在低于其Tm值约20的温度下进行的。填空题1DNA双螺旋结构模型是Wastson和Crick于 1953年提出的。2核酸的基本结构单位是 核苷酸 。脱氧核糖核酸在糖环 2位置不带羟基。3tRNA的二级结构为 三叶草形 形状，三级结构为 倒L型 形状。4两类核酸在细胞中的分布不同，DNA主要位于 细胞核 中，RNA主要位于 细胞质 中。5核酸分子中糖环与碱基之间的连键为_糖苷_键。核苷与核苷之间通过 磷酸二酯键 键连接成多聚体。6核酸的特征元素_P_。7 B型DNA双螺旋的两条多

24、核苷酸连为 反向、平行 方向的螺旋，螺距为_3.4nm_，每匝螺旋有_10_对碱基，每对碱基的转角是 36°。8在DNA分子中，一般来说G-C含量高时，比重_大_，Tm（熔解温度）则_高_，分子比较稳定。9在_退火_条件下，互补的单股核苷酸序列将缔结成双链分子。稀碱溶液可以水解_RNA 。10_m_RNA分子指导蛋白质合成，_t_RNA分子用作蛋白质合成中活化氨基酸的载体。11DNA变性后，紫外吸收_增加_，粘度_下降、浮力密度_升高_，生物活性将_丧失。12因为核酸分子具有_嘌呤_、_嘧啶_，所以在_260_nm处有吸收峰，可用紫外分光光度计测定。13维持DNA双螺旋结构稳定的主要

25、因素是_碱基堆积力_，其次，大量存在于DNA分子中的弱作用力如_氢键_，_离子键_和_范德华力_也起一定作用。14常见的环化核苷酸有_cAMP_和cGMP_。其作用是_第二信使_，他们核糖上的_3_位与_5_位磷酸-OH环化。15若DNA一条链的碱基顺序是5pCpTpGpGpApC3，则另一条链的碱基顺序是_3pGpApCpCpTpG5_。 问答1、 将核酸完全水解后可得到哪些组分?DNA和RNA的水解产物有何不同？答：核酸完全水解后可得到碱基、戊糖、磷酸三种组分。DNA和RNA的戊糖和嘧啶碱不同。DNA ：磷酸+脱氧核糖+碱基（A,T,C,G）RNA ：磷酸+核糖+碱基（

26、A,T,C,U）2、 画出核苷中两种C-N糖苷键，注意N1与N9。 3、几种重要的核苷酸结构：ATP、GTP；cAMP、cGMP。4、画出A=T 碱基配对的分子构造(包括氢原子)。5、简述B型DNA双螺旋结构模型的要点。6、在稳定的DNA双螺旋中，哪两种力在维系分子立体结构方面起主要作用？7、核酸变性特征，引起变性的因素，以及核酸变性时，伴随的物理化学性质的改变。8、核酸含量测定方法与原理。9、对一双链DNA而言，若一条链中（A+G）/（T+C）= 0.7，则：（1）互补链中（A+G）/（T+C）= ？（2）在整个DNA分子中（A+G）/（T+C）= ？（3）若一条链中（A+ T）/（G +C

27、）= 0.7，则互补链中（A+ T）/（G +C）= ？（4）在整个DNA分子中（A+ T）/（G +C）= ？10.、请说明DNA和RNA在组成、结构、功能上的不同之处。答: 不同。RNA 可以被水解成单核苷酸，而DNA 分子中的脱氧核糖2碳原子上没有羟基，所以DNA 不能被碱水解。                   第二章 蛋白质名词解释(英语解释)两性离子（d

28、ipolarion） 两性离子（英语：zwitterion）是总电荷为0，电中性的化合物，但是带正电和负电的原子不同。有些化学家将此术语限定为未具有相邻正负电荷的化合物。此定义将诸如氧化胺的化合物排除。两性离子为极性，通常易溶于水，难溶于大部分有机溶剂。In chemistry, a zwitterion (/tsvtr.a.n/ tsvit-r-eye-n; from German zwitter tsvt "hybrid" and formerly called a dipolar ion) is a neutral molecule with a positive a

29、nd a negative electrical charge, distinct from dipoles, at different locations within that molecule. Zwitterions are sometimes also called inner salts.必需氨基酸（essential amino acid）必需氨基酸指的是人体自身不能合成或合成速度不能满足人体需要，必须从食物中摄取的氨基酸。它是人体（或其它脊椎动物）必不可少，而机体内又不有合成的，必须从食物中补充的氨基酸，称必需氨基酸。对成人来讲必需氨基酸共有八种：赖氨酸、色氨酸、苯丙氨酸、甲硫

30、氨酸、苏氨酸、异亮氨酸、亮氨酸、缬氨酸。如果饮食中经常缺少上述氨基酸，可影响健康。它对婴儿的成长起着重要的作用。组氨酸为小儿生长发育期间的必需氨基酸，精氨酸、胱氨酸、酪氨酸、牛磺酸为早产儿所必需。An essential amino acid or indispensable amino acid is an amino acid that cannot be synthesized natively by the organism being considered, and therefore must be supplied in its diet.等电点(isoelectric poin

31、t, pI)等电点：在某一PH的溶液中，氨基酸或蛋白质解离成阳离子和阴离子的趋势或程度相等，成为兼性离子，呈电中性，此时溶液的pH成为该氨基酸或蛋白质的等电点。溶解度最小。The isoelectric point (pI), sometimes abbreviated to IEP, is the pH at which a particular molecule or surface carries no net electrical charge. The pI value can affect the solubility of a molecule at a given pH. Su

32、ch molecules have minimum solubility in water or salt solutions at the pH that corresponds to their pI and often precipitate out of solution.非蛋白质氨基酸(nonprotein amino acid) 不存在于蛋白质分子中而以游离状态和结合状态存在于生物体的各种组织和细胞的氨基酸。其不参与蛋白质合成，但有些是很重要的代谢物前体或中间产物，如瓜氨酸与鸟氨酸是合成精氨酸的中间产物。Aside from the 22 standard amino acids,

33、 there are many other amino acids that are called non-proteinogenic or non-standard. Those either are not found in proteins (for example carnitine, GABA), or are not produced directly and in isolation by standard cellular machinery (for example,hydroxyproline and selenomethionine).构型(configuration)与

34、 构象(conformation) The configuration of a molecule is the permanent geometry that results from the spatial arrangement of its bonds. The ability of the same set of atoms to form two or more molecules with different configurations is stereoisomerism. C

35、onfiguration is distinct from chemical conformation, a shape attainable by bond rotations. 构象是指一个分子中不改变共价键结构，仅单键周围的原子放置所产生的空间排布。一种构象转变为另一种构象时不要求共价键的断裂和重新形成，构象不会改变分子的光学活性。 蛋白质的一级结构(protein primary structure) 每种蛋白质中氨基酸按照一定的数目和组成进行排列，并进一步折叠成特定的空间结构前者我们称为蛋白质的一级结构， 蛋白质的一级结构包括：组成蛋白质的多肽链的数目；多肽链的氨

36、基酸顺序；多肽链内或链间二硫键的数目和位置。The primary structure of a peptide or protein is the linear sequence of its amino acid structure units, and partly comprises its overall biomolecular structure. The primary structure can often be specified by the sequence of amino acids along their backbone. However, mostly com

37、monly by disulfide bonds. The primary structure also requires specifying the cross-linking atoms.蛋白质的二级结构(protein secondary structure) 蛋白质二级结构指它的多肽链中有规则重复的构象，限于主链原子的局部空间排列，不包括与肽链其他区段的相互关系及侧链构象。二级结构主要有-螺旋、-折叠、-转角和无规卷曲。主要作用力为氢键。Within the long protein chains, there are regions in which the chains are

38、organized into regular structures known as alpha-helices and beta-pleated sheets. These are the secondary structures in proteins. There are also beta-turns and random coils in secondary structures. There secondary structures are held together by hydrogen bonds.结构域(domain)A protein domain i

39、s a conserved part of a given protein sequence and structure that can evolve, function, and exist independently of the rest of the protein chain. Each domain forms a compact three-dimensional structure and often can be independently stable and folded. Many proteins consist of sev

40、eral structural domains. One domain may appear in a variety of different proteins.在二级或者超二级结构基础上形成的特定的区域称为结构域蛋白质的三级结构(protein tertiary structure)(protein tertiary structure) In biochemistry and molecular biology, the tertiary structure of a protein or any other 

41、;macromolecule is defined by its three-dimensional structure through the atomic coordinates. Tertiary structure is formed by the packing of protein secondary structure elements into compact globular units called protein domains. 蛋白质的四级结构(protein quaternary structure) quaternary s

42、tructure is the arrangement of multiple folded protein or coiling protein molecules in a multi-subunit complex. 多肽（Polypeptides）多肽是氨基酸以肽链连接在一起而形成的化合物，它也是蛋白质水解的中间产物。1050个氨基酸组成的肽称为多肽； A polypeptide is a long, continuous, and unbranched peptide chain.氧结合蛋白Oxygen-Binding Proteins免疫球蛋白（Imm

43、unoglobulins） . a protein of animal origin with known antibody activity, synthesized by lymphocytes and plasma cells and found in serum and in other body fluids and tissues; abbreviated Ig. There are five distinct classes based on structural and antigenic properties: IgA, IgD, IgE, IgG, and IgM

44、. 血红蛋白（Hemoglobin）血红蛋白是高等生物体内负责运载氧的一种蛋白质，是使血液呈红色的蛋白。血红蛋白由四条链组成，两条链和两条链，每一条链有一个包含一个铁原子的环状血红素。氧气结合在铁原子上，被血液运输。Hemoglobin (/himlobn/); also spelled haemoglobin and abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloproteinin the red blood cells of all vertebrates1 (with the exception

45、 of the fish family Channichthyidae2) as well as the tissues of someinvertebrates. 疏水键(hydrophobic bond)疏水键是多肽链上的某些氨基酸的疏水基团或疏水侧链（非极性侧链），由于避开水而造成相互接近、粘附聚集在一起。它在维持蛋白质三级结构方面占有突出地位。The hydrophobic bond is important to form the structure of proteins. Structures of water-soluble proteins have a hydrophobi

46、c core in which side chains are buried from water, which stabilizes the folded state, and charged and polar side chains are situated on the solvent-exposed surface where they interact with surrounding water molecules. Minimizing the number of hydrophobic side chains exposed to water is the principal

47、 driving force behind the folding process,6 although formation of hydrogen bonds within the protein also stabilizes protein structure. 盐析(salting out)盐析一般是指溶液中加入无机盐类而使某种物质溶解度降低而析出的过程Salting out (also known as antisolvent crystallization, precipitation crystallization, or drowning out)1 is an effect

48、based on the electrolyte-nonelectrolyte interaction based on the fact that the non-electrolyte could be less soluble at high salt concentrations. It is used as method of separating proteins. The salt concentration needed for the protein to precipitate out of the solution differs from protein to prot

49、ein. This process is also used to concentrate dilute solutions of proteins. Dialysis can be used to remove the salt if needed. 蛋白质的变性(denaturation) 蛋白质的变性是指蛋白质收到某些物理或化学因素的影响，改变其分子内部结构和性质的作用。导致其三级结构和二级结构改变或破坏，从而使其理化性质改变和生物活性丧失。 Denaturation is a process which protein loses the quaternary structure, t

50、ertiary structure and secondary structure, which is present by application of some external stress or chemical compound or heat.蛋白质的复性(renaturation) 凝胶电泳（gel electrophoresis）Gel electrophoresis is a method for separation and analysis of macromolecules (DNA, RNA and proteins) and

51、their fragments, based on their size and charge是一大类技术，被科学工作者用于分离不同物理性质（如大小、形状、等电点等）的分子。凝胶电泳通常用于分析用途，但也可以作为制备技术，在采用某些方法，如质谱、聚合酶链式反应、克隆、DNA测序或者免疫印迹检测之前，进行部分提纯分子。 层析（chromatography）is the collective term for a set of laboratory techniques for the separation of mixtures. Chromatography ma

52、y be preparative or analytical. The purpose of preparative chromatography is to separate the components of a mixture for more advanced use (and is thus a form of purification). Analytical chromatography is done normally with smaller amounts of material and is for measuring the relative proporti

53、ons of analytes in a mixture. The two are not mutually exclusive.层析是色层分析的简称，利用各组分物理性质的不同将多组分混合物进行分离及测定的方法。有吸附层析、分配层析两种。一般用于有机化合物、金属离子、氨基酸等的分析。 填空题1蛋白质多肽链中的肽键是通过一个氨基酸的_氨_基和另一氨基酸的_羧_基连接而形成的。2大多数蛋白质中氮的含量较恒定，平均为_16_%，如测得1克样品含氮量为10mg,则蛋白质含量为_6.25_%。3在20种氨基酸中，酸性氨基酸有_天冬氨酸_和_谷氨酸_2种，具有羟基的氨基酸是_丝氨酸_和_苏氨酸_，能形成二

54、硫键的氨基酸是_半膀胱酸_。4蛋白质中的_苯丙氨酸_、_酪氨酸_和_色氨酸_3种氨基酸具有紫外吸收特性，因而使蛋白质在280nm处有最大吸收值。5精氨酸的pI值为10.76，将其溶于pH = 7的缓冲液中，并置于电场中，则精氨酸应向电场的_负_方向移动。6组成蛋白质的20种氨基酸中，含有咪唑环的氨基酸是_组氨酸_，含硫的氨基酸有_半胱氨酸_和_甲硫氨酸_。7蛋白质的二级结构最基本的有两种类型，它们是_螺旋_和_折叠_。8-螺旋结构是由同一肽链的_羰基_和_氨基_间的_氢键_键维持的，螺距为_0.54nm_，每圈螺旋含_3.6_个氨基酸残基，每个氨基酸残基沿轴上升高度为_0.15nm_。天然蛋白

55、质分子中的-螺旋大都属于_右_手螺旋。9在蛋白质的-螺旋结构中，在环状氨基酸_脯氨酸、羟脯氨酸_存在处局部螺旋结构中断。10球状蛋白质中有_极性_侧链的氨基酸残基常位于分子表面而与水结合，而有_疏水性_侧链的氨基酸位于分子的内部。11氨基酸与茚三酮发生氧化脱羧脱氨反应生成_蓝紫_色化合物，而_脯氨酸_与茚三酮反应生成黄色化合物。12维持蛋白质的一级结构的化学键有_肽键_和_二硫键_；维持二级结构靠_氢_键；维持三级结构和四级结构靠_次级_键，其中包括_氢键_、_疏水键_、_离子键_和_范德华力_。13稳定蛋白质胶体的因素是_表面的水化膜_和_同性电膜_。14GSH的中文名称是_谷胱甘肽_，它的

56、活性基团是_巯基_，它的生化功能是_体内重要的抗氧化剂和自由基清除剂，参与机体氧化还原反应，把机体内有害的毒物转化为无害的物质，排泄出体外_。15加入低浓度的中性盐可使蛋白质溶解度_增加_，这种现象称为_盐溶_，而加入高浓度的中性盐，当达到一定的盐饱和度时，可使蛋白质的溶解度_减小_并_沉淀析出_，这种现象称为_盐析_，蛋白质的这种性质常用于蛋白质 分离_。16用电泳方法分离蛋白质的原理，是在一定的pH条件下，不同蛋白质的_带电荷量_、_分子大小_和_分子性状_不同，因而在电场中移动的_方向_和_速率_不同，从而使蛋白质得到分离。17氨基酸处于等电状态时，主要是以_两性离子_形式存在，此时它的

57、溶解度最小。18鉴定蛋白质多肽链N末端常用的方法有二硝基氟苯法(FDNB，DNFB)_、_氰酸盐法_和_二甲基氨基萘磺酰氯法_。19测定蛋白质分子量的方法有_沉降法_、_凝胶过滤法_和_SDS-聚丙烯酰胺凝胶电泳法（SDS-PAGE法）_。20谷氨酸的pK1(-COOH)2.19, pK2 (-NH+3 ) = 9.67, pKR(R基)= 4.25，谷氨酸的等电点为_3.22_。21将分子量分别为a（90 000）、b（45 000）、c（110 000）的三种蛋白质混合溶液进行凝胶过滤层析，它们被洗脱下来的先后顺序是_c,a,b_。问答1、蛋白质是生命活动最重要的物质基础，简述蛋白质有哪些

58、重要生物学功能？简述蛋白质四级结构的基本定义。答：生物学功能：1、运输（血红蛋白）；2、催化（酶蛋白）；3、信息交流（细胞膜糖蛋白）；4、结构；5、免疫（抗体蛋白）。 四级结构：一级：氨基酸排列形成肽链；二级：多肽链有规则重复排列，主链原子的局部空间排列（靠氢键维系）；三级：二级结构基础上进一步盘绕（靠次级键维系）；四级：三级结构亚基与亚基间的空间排布（亚基间相互作用）。2、什么是蛋白质的一级结构？为什么说蛋白质的一级结构决定其空间结构？答：蛋白质的一级结构包括组成蛋白质的多肽链数目，多肽链的氨基酸顺序，以及多肽链内或链间二硫键的数目和位置。多肽链氨基酸顺序是蛋白质生物功能的基础，他影响着蛋白

59、质的高级结构从而直接影响其生物功能。1、 什么是蛋白质的空间结构？蛋白质的空间结构与其生物功能有何关系？蛋白质的空间结构是指蛋白质分子中原子和基团在三维空间上的排列、分布及肽链走向。蛋白质的空间结构决定蛋白质的功能。空间结构与蛋白质各自的功能是相适应的。4、什么是蛋白质的变性？变性的机制是什么？举例说明蛋白质变性在实践中的应用。答：定义：蛋白质在物理或化学作用下，失去生物活性的过程称作蛋白质变性。变性机制：蛋白质在某些物理和化学作用下，其特定的空间结构发生改变，从而导致理化性质的改变，失去生物活性。应用：重金属中毒，喝牛奶解毒。利用牛奶中的蛋白质与重金属发生作用，蛋白质发生变性，使得金属离开人体与蛋白质结合。5、假定有1mmol的五肽，酸水解生成2mmol谷氨酸，1mmol赖氨酸，没有能够定量回收其它氨基酸，将原来的五肽用胰蛋白酶水解