名词解释

1.annealing or renaturation 复性Once the two strands of DNA separate, they can, under the proper conditions,
come back together again. This is called annealing or renaturation.
2.autoregulation a protein controls its own synthesis, is called autoregulation.
3.A physical map of DNA based on restriction sites is called a restriction Map
4.Architectural transcription factors whose sole purpose 唯一目的seems to be to change the shape of a DNA
control region so that other proteins can interact successfully to stimulate transcription.
5.An enhanceosome 增强体is a complex of enhancer DNA with activators contacting this DNA
6.enzymes酶all living things carry out countless chemical reactions and that these reactions are accelerated加
快, or catalyzed, by proteins called enzymes。

7.nucleotides 核苷酸The subunits of DNA and RNA are nucleotides, which are nucleosides核苷with a
phosphate group attached through a phosphoester bond
8.T m denaturation DNA变性When a DNA solution is heated enough, the noncovalent非共价键forces that
hold the two strands together weaken and finally break. When this happens, the two strands come apart in a process known as DNA denaturation, or DNA melting. The temperature at which the DNA strands are half denatured is called the melting temperature, or T m.
9.Hybridization杂交: putting together a hybrid of two different nucleic acids
10.C-value paradox.C值悖论The observation that more complex organisms will not always have more DNA
(C-value) than simple organisms is called the C-value paradox.
11.ProteinsPrimary Structure蛋白质一级结构The linear order of amino acid constitudes a protein’s primary
structure
12.secondary structure蛋白质二级结构a polypeptide (primary structure) gives rise to that molecule’s local
shape α-helix β-pleated sheetβ-turn
13.tertiary structure. 蛋白质三级结构The total three-dimensional shape of a polypeptide is its tertiary structure.
14.Quaternary Stucture蛋白质四级结构The highest level of protein structure which is the way two or more
individual polypeptides fit together in a complex protein
15.Ribosomes 核糖体a re the cell’s protein factories. Bacteria contain 70S ribosomes with two subunits, called
50S and 30S. Each of these contains ribosomal RNA and many proteins
16.open reading frame.开放阅读框The DNA sequence including a translation initiation codon, a coding
region,and a termination codon, is called an open reading fr ame.
17.DispersiveReplication:分散复制DNA is fragmented, both new and old DNA coexist in the same strand
18.silent mutation 沉默突变If a mutation results in a different codon for the same amino acid it is a silent
mutation
19.Restriction endonucleases限制性内切核酸酶recognize specific sequences in DNA molecules and make cuts
in both strands
20.V ectors载体as DNA carriers to allow replication of recombinant DNAs
21.pBR322；It contains two antibiotic抗生genes and a variety of unique restriction sites.
22.Genomic Libraries基因组信息库A genomic library contains clones of all the genes from a species genome
23.Cosmids黏性质粒For cloning large DNA fragmentsBehave as plasmid and phage
24.Ion-Exchange Chromatographyuses a resin树脂to separate substances according to their charges
25.Microsatellite DNA微卫星DNA: short DNA sequence (usually 2–4 bp) repeated many times in tandem连
接在一起. A given microsatellite is found in varying lengths, scattered around a eukaryotic genome.
26.Minisatellite DNA is a sequence of bases repeated several times, also called DNA fingerprint.
27.In Situ Hybridization原位混合法One can hybridize labeled probes to whole chromosomes to locate genes or
other specific DNA sequences. This type of procedure is called in situ hybridization
28.Nuclear run-on transcription is a way of ascertaining which genes are active in a given cell by allowing
transcription of these genes to continue in isolated nuclei.
29.Footprinting is a means of finding the target DNA sequence, or binding site, of a DNA binding protein.
30.SELEX is a method to find RNA sequences that interact with other molecules, even proteins
31.RNA聚合酶是在DNA模板指导下，以四种核糖核苷酸为低物，催化合成新生RNA链的酶
32.promoters启动子The se polymerase binding sites are called promoters.
33.the σ-factor can promoter tight binding , at least to certain DNA sitesSigma stimulates initiation , but not
elongation of transcription . Sigma can be reused by different core polymerases , and the core ,not σ, governs rifampicin sensitivity or resistance.
34.σcycle 随着加入不同的核心酶，σ都可与之结合并作用于不同类型的DNA,起始转录。

σcycle 因此
认为全酶与启动子结合，DNA局部解链，开始合成RNA链。

随着聚合酶向前移动RNA链延长到一定长度，σ因子脱离，与新的核心酶结合然后开始起始新的RNA链。

这个过程就称之为σcycle 。

35.Intrinsic terminator内在终止子（Rho-independent) , function with the RNA polymerase by itself without
help from other proteins .
36.Structural genes 结构基因for enzymes in a specific biosynthetic 生物合成pathway途径whose expression
is coordinately controlled
c represso The “something”that can turn off the lac operon is the lac repressor乳糖阻遏物.
38.The term negative control implies that the operon 操纵子is turned on unless something intervenes 干涉to
stop it
39.positive control is the opposite of negative control; that is, the op eron is turned off (actually, turned down to a
basal level) unless something intervenes to turn it on.
40.Enhancers 增强子are nonpromoter DNA elements that bind protein factors and stimulate transcription
41.Core subunits核心亚基, which are related in structure and function to the core subunits of bacterial RNA
polymerases
mon subunits共有亚基, which are found in all three nuclear RNA polymerases
43.Nonessential subunits, which are conditionally 有条件dispensible 非必须for enzyme activity
44. 转录泡（transcription bubble）：在转录延长过程中，由局部打开的DNA双链、RNA聚合酶核心酶
及新生成的RNA三者结合在一起的复合体，为空泡状结构，又称转录复合...
45. TATA box Found on the nontemplate strandVery similar to the prokaryotic -10 box
There are frequently TATA-less promoters
46. Housekeeping genes持家基因that are constitutively active in nearly all cells as they control
common biochemical pathways生化途径
47. Enhancers are DNA elements that stimulate transcription.
48. Silencers,沉默子by contrast, are DNA elements that depress transcription
49. general transcription factors：These proteins appear to stimulate transcription by interacting with
other proteins called general transcription factors
50. Preinitiation complex起始复合物The combination of RNA polymerase and general transcription
factors assembled at a promoter just before transcription begins.
51. TFIID is a complex protein containing a TATA-box binding protein (TBP) and 8–10 TBP-associated
factors (TAFⅡS).
52. The TAFⅡS serve two obviousfunctions: interacting with core promoter elements and interacting
with gene-specific transcription factors
53. TFⅡB；one to interact with TFIID and the other to interact with TFIIF/polymerase.
54. TFIIH is the last general transcription factor to join the preinitiation complex
55. TFIIIA bound to the internal promoter of the 5S rRNA gene and stimulated its transcription
56. activators：transcription of active genes in cells rises above (frequently far above) the basal level. To
provide the needed extra boost in transcription,
57. Homeodomains同源异形结构域：These domains contain about 60 amino acidsResemble the
helix-turn-helix proteins in structure and function Found in a variety of activators
58. Zinc FingersEach zinc ion is complexed By the two cyste。

nes and two histidines组氨酸in each
repeat unit to form a finger-shaped domain.
59. The GAL4 protein is a yeast activator that controls a set of genes responsible for metabolism 新陈代
谢of galactose半乳糖
60. upstream activating sequences, or UASGs.Each of these GAL4-responsive genes contains a
GAL4 target site upstream of the transcription start site. These target sites are called upstream activating sequences, or UASGs.
61. The Nuclear Receptors：These proteins interact with a variety of steroid类固醇and other
hormones激素that diffuse through通过the cell membrane.细胞膜
62. Recruitment: A process that leads to the tight binding of RNA polymerase holoenzyme to a
promoter.
63. Insulators隔离子block activation of unrelated genes by nearby enhancers
64. Enhancer-blocking增强子屏蔽activity: insulator between promoter and enhancer prevents the
promoter from being activated
65. Barrier 阻碍物activity: insulator between promoter and condensed, repressive chromatin prevents
promoter from being repressed
66. Sliding model滑动模型Activator bound to束缚于an enhancer and slides滑向along DNA from
enhancer to promoter but be stopped
67. Looping model环化模型Two insulators flank位于什么两侧an enhancer, when bound 限制they
interact with each other isolating enhancer
68. Sumoylation修饰作用is the attachment of the polypeptide SUMO which can target for
incorporation into compartments of the nucleus
69. Signal Transduction转导Pathways途径Signal transduction pathways begin with a signaling
molecule信号分子interacting with a receptor on the cell surfaceThis interaction sends the signal into the cell and frequently leads to altered gene expression
70. Chromatin is a complex continuum of DNA and proteins, packed together to form the genetic
material of chromosomes
71. histones or histones Eukaryotic DNA combines with basic protein molecules called histones to form
structures known as histones
72. Nucleosome Positioning核小体定位activators force nucleosomes to take up positions around, not
within, promoters
73. Euchromatin（常染色质）: relatively extended and open chromatin that is potentially active
74. Heterochromatin （异染色质）: very condensed with its DNA inaccessible
75. telomere position effect：Formation of at tips of yeast chromosomes (telomeres) with silencing of the
genes is the telomere position effect (TPE)
76. Most higher eukaryotic genes coding for mRNA and tRNA, and a few coding for rRNA, are
interrupted by unrelated regions called introns
77. The other parts of the gene, surrounding the introns, are called exons
78. RNA splicing:The process of cutting introns out of immature 不成熟RNAs and stitching固定
together the exons to form the final product is called RNA splicing.
79. hnRNAs. precursor is part of a pool of 一些large nuclear RNAs called hnRNAs.
80. a spliceosome :Splicing takes place on a particle called a spliceosome
81. 选择性剪接一个基因的初始转录产物在不同的分化细胞、不同的发育阶段、甚至不同的生理状态下，
通过不同的剪接方式，可以得到不同的成熟mRNA和蛋白质产物，称为选择性剪接
82. Self-Splicing RNAs :some RNAs could splice themselves without aid from a spliceosome or any
other proteins.
83. polyadenylation ;The process of adding poly(A) to RNA is called polyadenylation
84. Turnover of Poly(A ):Poly(A) is constantly经常being shortened by RNases and lengthened by a
cytoplasmic poly(A) polymerase, which called Turnover of Poly(A).
85. Ribosomal RNAs are made in eukaryotic nucleoli 核仁as precursors that must be processed to
release mature rRNAs
86. RNase III is the enzyme that performs at least the initial cleavages that separate the individual large
rRNAs
87. RNA Editing Editing occurs in the 3’ 5’ direction by successive action of one or more guide操纵
RNAs
88. 反义RNA(antisense RNA)是一类能与特异mRNA互补的小分子量、可扩散的DNA转录物,它能够从
翻译水平、转录水平和核酸复制水平上高度特异地抑制靶基因表达.
89. RNA interference (RNAi )Double-stranded RNA (dsRNA) lead to some gene silence, called RNA
interference (RNAi
90. Trigger 引发dsRNA is degraded into 21-23 nt fragments(siRNAs) by an RNase III-like enzyme
called Dicer
91. MicroRNAs (miRNA) are 18-25 nt RNAs produced naturally in plant and animal cells by cleavage
from 75nt stem-loop茎环结构precursor RNA
92. cDNA-AFLP is a variation of AFLP, which is used to quantify differences in gene expression levels
93. Suppression Subtractive Hybridization (SSH) is a powerful technique to identify a set of genes
differentially expressed in two cell samples in the absence of sequence information.
94. (SAGE) is a powerful tool that allows the analysis of overall gene expression patterns with digital
analysis
95. Gene chips are devices not much larger than postage stamps. They are based on a glass substrate
wafer and contain many tiny cells — 400,000 is common. Each holds DNA from a different gene.
The array排列of cells makes it possible to carry out a very large number of genetic tests on a sample at one time.
96. DNA microarrays can be used to detect DNA (as in comparative genomic hybridization), or detect
RNA (most commonly as cDNA after reverse transcription) that may or may not be translated into proteins.
97. mutation A change in the sequence of bases constitutes构成a mutation
98. nucleotides The subunits of DNA and RNA are nucleotides, which are nucleosides核苷with a
phosphate group attached through a phosphoester bond
99. C-value is the DNA content per haploid单一cell.
100. M essenger RNAs carry the genetic information from the genes to the ribosomes, which synthesize polypeptides
101. H ybridization is the ability of one single-stranded nucleic acid to form a double helix with another single strand of complementary base sequence
102. D NA typing: The use of molecular techniques to identify a particular individual
103. i n situ hybridization；One can hybridize labeled probes to whole chromosomes to locate genes or other specific DNA sequences. This type of procedure is called in situ hybridizatio n
cis-acting A term that describes a genetic element, such as an enhancer, a promoter, or an operator, that must be on the same chromosome in order to infl uence a gene’s activity.
104.Run-off transcription: Accuracy and efficiency of transcription in v itro体外Begin by cutting the cloned gene, then transcribe this truncated 缩短gene in vitro. When the RNA polymerase reaches the end of the shortened gene, it falls off离开and releases the run-off transcript.
105.Restrction Mapping: A physical map tells us about the spatial 空间arrangement 布置of physical “landmarks标志,” such as restriction sites, on a DNA molecule. A physical map of DNA based on restriction sites is called a restriction Map.
106.Southern Blots: Identifying specific DNA fragments in genomic DNA determine the copy number of a particular gene in genomic DNA染色体组DNA isolated from the organism
107.N orthern blot A Northern blot is similar to a Southern blot, but it contains electrophoretically separated RNAs instead of DNAs. The RNAs on the blot can be detected by hybridizing them to a labeled probe. The
intensities 强度of the bands reveal the relative amounts of specific RNA in each.
108.DNase footprinting DNase轨迹is performed by binding the protein to its end-labeled DNA target, then attacking the DNA–protein complex with DNase. When the resulting DNA fragments are electrophoresed, the protein binding site shows up as a gap, or “footprint”in the pattern where the protein protected the DNA from degradation.
109.DMS footprinting，using DNA methylating agent DMS and piperidine哌啶, the DNA is broken at the methylated sites. Unmethylated sites show up on electrophoresis of the labeled DNA fragments and demonstrate where the protein bound to the DNA.
110.cDNA ---a complementary DNA copy of an RNA (usually an mRNA)
111.cDNA library --- A set of clones representing as many as possible of the mRNAs in a given cell type at a given time.
112.Gene knockout：create deliberate mutations in a particular gene in a living organism
113.Restriction endonucleases the enzyme that can recognize specific sequences in DNA and make cuts in both strands.
114.UP element ;some very strong promoters have an additional element further upstream called an UP element UP元件.
115.positive control additional positive factor, responds to low glucose葡萄糖by stimulating transcription of the lac operon
116.autoregulation.a protein controls its own synthesis, is called autoregulation.
117.Riboswitches;Small molecules can act directly on the 5’-UTRs of mRNAs to control their expression
118.aptamer ;Region that binds to the ligand 陪基is an aptamer适配子
119.Enhancers are nonpromoter DNA elements that bind protein factors and stimulate transcription
120.Housekeeping genes持家基因that are constitutively active in nearly all cells as they control common biochemical pathways生化途径
121.Silencers, by contrast, are DNA elements that depress transcription
122.Chromatin is a complex continuum of DNA and proteins, packed together to form the genetic material of chromosomes.
123. A chromosome is a unique part of the spiral 螺旋of DNA, which contains within it a number of gene sequences, nucleotides and regulatory elements
124.T he RNA splicing process of cutting introns out of immature 不成熟RNAs and stitching固定together the exons to form the final product is called RNA splicing.
125.This methylation cluster formed a structure we call a cap
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