分子生物学名词解释英文

1. DNA Denaturation(变性) When duplex DNA molecules are subjected to conditions of pH ,temperature,

or ionic strength that disrupt base-paring interactions, the DNA molecule has lost its’ native

conformation, and double helix DNA is separated to single strand DNA as individual randome coils.

That is, the DNA is denatured.

2. Renaturation（复性）Removing the denaturation factors slowly or in proper conditions, the denatured

DNA (ssDNA) restore native structure (dsDNA) and functions. This process is dependent on both DNA

concentration and time.

3. Hybridization （核酸分子杂交）when heterogeneous DNA or RNA are put together, they will become to

heteroduplex via the base-pairing rules during renaturation if they are complementary in parts (not

completely). This is called molecular hybridization.

4. Hyperchromic effect （增色效应）The absorbance at 260 nm of a DNA solution increases when the

double helix is separated into single strands because of the bases unstack.

5. Ribozyme （核酶）are the RNA molecules with catalytic activity. The activity of these ribozymes often

involves the cleavage of a nucleic acid.

6. De novo synthesis (从头合成)De novo synthesis of nucleotides begins with their metabolic precursors:

amino acids, ribose-5-phosphate, one carbon units, CO2. mostly in liver.

7. Salvage pathways （补救合成）Salvage pathways recycle the free bases and nucleosides released from

nucleic acid breakdown. Mostly in brain and marrow.

8. Semi-conservative replication (半保留复制）DNA is synthesized by separation of the strands of a

parental duplex, each then acting as a template for synthesis of a complementary strand based on the

base-paring rule. Each daughter molecule has one parental strand and one newly synthesized strand.

9. Telomere（端粒）： Specialized structure at the end of a linear eukaryotic chromosome, which consists of

proteins and DNA, tandem repeats of a short G-rich sequence on the 3 ' ending strand and its

complementary sequence on the 5' ending strand, allows replication of the extreme 5' ends of the DNA

1

without loss of genetic information and maintains the stability of eukaryote chromosome.

10. Telomerase（端粒酶） An RNA-containing reverse transcriptase that using the RNA as a template, adds

nucleotides to the 3 ' ending strand and thus prevents progressive shortening of eukaryotic linear DNA

molecules during replication.

11. Reverse transcription (逆转录）Synthesis of a double-strand DNA from an RNA template.

12. Reverse transcriptase (逆转录酶）A DNA polymerase that uses RNA as its template.

activity: RNA-dependent DNA polymerase; RNAse H;DNA-dependent DNA polymerase

13. The central dogma (中心法则）It described that the flow of genetic information is from DNA to RNA and

then to protein. According to the central dogma, DNA directs the synthesis of RNA, and RNA then

directs the synthesis of proteins.

14. asymmetric transcription（不对称转录） 1..Transcription generally involves only short segments of a

DNA molecule, and within those segments only one of the two DNA strands serves as a template.

template strand of different genes is not always on the same strand of DNA. That is, in any

chromosome, different genes may use different strands as template.

15. template strand （模板链）The DNA strand that serves as a template for transcription. (The relationship

between template and transcript is base paring and anti-parallel)

16. non-template strand (or coding strand)（编码连）The DNA strand that opposites to the template

strand.(Note that it has the same sequence as the synthesized RNA, except for the replacement of U

with T )

17. promoter is the DNA sequence at which RNA polymerase binds to initiate transcription. It is always

located on the upstream of a gene.

18. Split genes (断裂基因)Split genes are those in which regions that are represented in mature mRNAs or

structural RNAs (exons) are separated by regions that are transcribed along with exons in the primary

RNA products of genes, but are removed from within the primary RNA molecule during RNA processing

2

steps (introns).

19. Exon(外显子) can be expressed in primary transcript and are the sequences that are represented in

mature RNA molecules, it encompasses not only protein-coding genes but also the genes for various

RNA (such as tRNAs or rRNAs)

20. Intron（内含子） can be expressed and be the intervening nucleotide sequences that are removed from

the primary transcript when it is processed into a mature RNA.

21. Spliceosome（剪切体） A multicomponent complex contains proteins and snRNAs that are involved in

mRNA splicing.

22. Translation（翻译） The process of protein synthesis in which the genetic information present in an

mRNA molecule (transcribed from DNA) determines the sequence of amino acids by the genetic codons.

Translation occurs on ribosomes.

23. genetic codon（密码子） The genetic code is a triplet code read continuously from a fixed starting point

in each mRNA, also called triplet. Genetic code defines the relationship between the base sequence of

mRNA and the amino acid sequence of polypeptide.

24. Degeneracy of code（密码子简并性） One codon encodes only one amino acid;

More than 2 codons can encode the same amino acid;

Most codons that encode the same amino acid have the difference in the third base of the codon.

25. ORF（开放阅读框架） The nucleotideacids sequences in mRNA molecule from 5’AUG to 3’ stop codon

(UAA UAG UGA). It consists of a group of contiguous nonoverlapping genetic codons encoding a

whole protein. Usually, it includes more than 500 genetic codons.

26. Shine-Dalgarno sequence（SD） is a sequence upstream the start codon in prokaryotic mRNA that can

base pairs to a •UCCU• sequence at or very near the 3' end of 16S rRNA, thereby binding the mRNA

and small ribosomal subunit by each other.

27. Polyribosome（多聚核糖体） Ribosomes(10~100) are tandemly arranged on one mRNA and move in the

3

direction of 5’ to 3’.Such a complex of one mRNA and a number ofribosomes is called polyribosome.

28. signal peptide（信号肽） It is a short conservative amino terminal sequence (13~36AA) that exists on

a newly synthesized secretory protein. It can direct this protein to a specific location

within the cell. It is subsequently cleaved away by signal peptidase; also called signal sequence and

targeting sequence.

29. Operon（操纵子）: Bacteria have a simple general mechanism for coordinating the regulation of genes

whose products are involved in related processes: the genes are clustered on the chromosome and

transcribed together. Most prokaryotic mRNAs are polycistronic. The single promoter required to

initiate transcription of the cluster is the point where expression of all of the genes is regulated. The

gene cluster, the promoter, and additional sequences that function in regulation are together called an

operon. Operons that include 2 to 6 genes transcribed as a unit are common; some operons contain 20

or more genes.

30. Housekeeping gene（管家基因）Genes that are expressed at a fairly consistent level throughout the cell

cycle and from tissue to tissue. Usually involved in routine cellular metabolism. Often used for

comparison when studying expression of other genes of interest.

31. Trans-acting factors（反式作用因子）：Usually considered to be proteins, that bind to the cis-acting

sequences to control gene expression. The properties of different trans-acting factors:

subunits of RNA polymerase

bind to RNA Polymerase to stabilize the initiation complex

bind to all promoters at specific sequences but not to RNA Polymerase (TFIID factor which binds to the

TATA box)

bind to a few promoters and are required for transcription initiation

32. Cis-acting elements（顺式作用元件）：DNA sequences in the vicinity of the structural portion of a gene

that are required for gene expression. The properties of different cis-acting elements:

4

contain short consensus sequences

modules are related but not identical

not fixed in location but usually within 200 bp upstream of the transcription start site

a single element is usually sufficient to confer a regulatory response

can be located in a promoter or an enhancer

assumed that a specific protein binds to the element and the presence of that protein is

developmentally regulated

33. Southern blotting：Genomic DNA (from tissues or cells) are cut by RE, separated by gel

electrophoresis and denatured in solution, then transferred to a nitrocellulose membrane for detecting

specific DNA sequence by hybridization to a labeled probe. It can be used to quantitative and

qualitative analyze genomic DNA, or analyze the recombinant plasmid and bacteriophage (screening

DNA library).

34. Northern blotting: RNA samples (from tissues or cells) are separated by gel electrophoresis and

denatured in solution, then transferred to a nitrocellulose membrane for detecting specific sequence by

hybridization to a labeled probe. It can be used to detect the level of specific mRNA in some tissues

(cells) and to compare the level of same gene expression in different tissues (cells) or at different

development period.

35. Western blotting：rotein samples are separated by PAGE electrophoresis, then electro-transferred to NC

membrane. The proteins on NC membrane hybridize with a specific antibody (1st antibody ), then the

target protein binding with antibody is detected with a labeled secondary antibody (2nd antibody).

Also called immunoblotting. It can be used to detect the specific protein, semi-quantify specific protein,

etc.

36. PBlotting technique（印迹）:Transfer (blot) biological macromolecules separated in the gel and fix them

to nitrocellulose/nylon membrane by diffusion, electro-transferring or vacuum absorption, then detect

5

it.

37. Nucleic acid probe（探针）:DNA or RNA fragment labeled with radioisotope, biotin or

fluorescent, is used to detect specific nucleic acid sequences by hybridization

38. PCR: PCR is a technique for amplifying a specific DNA segment in vitro. The reaction system include

DNA template, Taq DNA pol, dNTP，short oligonucleotide primers, buffer containing Mg2+. The process

including 3 steps: denature, annealing, extension

39. DNA coloning（克隆）:To clone a piece of DNA, DNA is cut into fragments using restriction enzymes. The

fragments are pasted into vectors that have been cut by the same restriction enzyme to form

recombinant DNA. The recombinant DNA are needed to transfer and maintain DNA in a host cell. This

serial process and related technique are called DNA coloning or genetic engineering.

40. Genomic DNA library(基因组DNA文库) A genomic library is a set of clones that together represents

the entire genome of a given organism. The number of clones that constitute a genomic library depends

on (1) the size of the genome in question and (2) the insert size tolerated by the particular cloning

vector system. For most practical purposes, the tissue source of the genomic DNA is unimportant

because each cell of the body contains virtually identical DNA (with some exceptions).

41. cDNA library（cDNA文库）:A cDNA library represents a sample of the mRNA purified from a particular

source (either a collection of cells, a particular tissue, or an entire organism), which has been converted

back to a DNA template by the use of the enzyme reverse transcriptase. It thus represents the genes that

were being actively transcribed in that particular source under the physiological, developmental, or

environmental conditions that existed when the mRNA was purified.

42. α-complementation（α互补）:Some plasmid vectors such as pUC19 carry the alpha fragment of the lac

Z gene. The alpha fragment is the amino-terminus of the beta-galactosidase. Typically, the mutant E. coli

host strain only carry the omega fragment, which is the carboxy-terminus of the protein. Either omega

6

or alpha fragment alone is nonfunctional. When the vector containing lac Z introduced into mutant E.

coli, both the alpha and omega fragments are present there is an interaction and a functionally intact

beta-galactosidase protein can be produced. This interaction is called alpha complementation.

43. Secondary messenger(第二信使) are some small signal molecules that are generated in the cell in

response to extracellular signals. They can activate many other downstream components. The most

important second messengers are: Ca2+, cAMP, cGMP, DAG, IP3, Cer, AA and its derivatives, etc.

44. Adaptor protein（衔接蛋白）A specialized protein that links protein components of the signaling

pathway, These proteins tend to lack any intrinsic enzymatic activity themselves but instead mediate

specific protein-protein interaction that drive the formation of protein complexes.

45. Scaffolding protein（支架蛋白）A protein that assembles interacting signaling proteins into

multimolecular, it recruits downstream effectors in a pathway and enhances specificity of the signal.

46. Oncogene（癌基因） A gene whose product is involved either in transforming cells in culture or in

inducing cancer in animals including virus oncogene（v-onc）and cellular-oncogene（c-onc ）。Most

oncogene are mutant forms of normal genes（proto- oncogene）involved in the control of cell growth or

division.

47. Tumor-suppressor genes（抑癌基因）A kind of negative regulatory gene which can check cell-cycle

progression，and hold cells in quiescence or even lead cells to commit suicide unless conditions are

appropriate for cell-cycle progression，means that they can prevent cells from becoming cancerous.(Rb

genep53 gene)

48. G-protein: GTP-binding protein, a membrane-associated protein, consists of α,b and r subunit of the

G-protein binds GTP or GDP,when the α subunit has GTP bound, the br-subunit leave, and the G-protein are

active which can active AC then induce biological effect.

7