1.DNA Denaturation(变性) When duplex DNA molecules are subjected to conditions of pH ,temperature,
or ionic strength that disrupt ba-paring interactions, the DNA molecule has lost its’native conformation, and double helix DNA is parated 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 ba-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 increas when the
double helix is parated into single strands becau of the bas unstack.
5.Ribozyme （核酶）are the RNA molecules with catalytic activity. The activity of the 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, ribo-5-phosphate, one carbon units, CO2. mostly in liver.
7.Salvage pathways （补救合成）Salvage pathways recycle the free bas and nucleosides relead from
nucleic acid breakdown. Mostly in brain and marrow.
8.Semi-conrvative replication (半保留复制）DNA is synthesized by paration of the strands of a
parental duplex, each then acting as a template for synthesis of a complementary strand bad on th
e ba-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 quence on the 3 ' ending strand and its complementary quence on the 5' ending strand, allows replication of the extreme 5' ends of the DNA
without loss of genetic information and maintains the stability of eukaryote chromosome.
10.Telomera（端粒酶）An RNA-containing rever transcripta 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.Rever transcription (逆转录）Synthesis of a double-strand DNA from an RNA template.
12.Rever transcripta (逆转录酶）A DNA polymera that us RNA as its template.
activity: RNA-dependent DNA polymera; RNA H;DNA-dependent DNA polymera
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 gments of a
DNA molecule, and within tho gments only one of the two DNA strands rves as a template.
2.The template strand of different genes is not always on the same strand of DNA. That is, in any
chromosome, different genes may u different strands as template.
between template and transcript is ba paring and anti-parallel)
<-template strand (or coding strand)（编码连）The DNA strand that opposites to the template
strand.(Note that it has the same quence as the synthesized RNA, except for the replacement of U with T )
17.promoter i s the DNA quence at which RNA polymera binds to initiate transcription. It is always
located on the upstream of a gene.
18.Split genes (断裂基因)Split genes are tho in which regions that are reprented in mature mRNAs or
structural RNAs (exons) are parated 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
steps (introns).
19.Exon(外显子) can be expresd in primary transcript and are the quences that are reprented in
mature RNA molecules, it encompass not only protein-coding genes but also the genes for various RNA (such as tRNAs or rRNAs)
20.Intron（内含子）can be expresd and be the intervening nucleotide quences that are removed from
the primary transcript when it is procesd 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 prent in an
mRNA molecule (transcribed from DNA) determines the quence of amino acids by the genetic codons.
Translation occurs on ribosomes.
in each mRNA, also called triplet. Genetic code defines the relationship between the ba quence of mRNA and the amino acid quence 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 ba of the codon.
25.ORF（开放阅读框架）The nucleotideacids quences 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 quence（SD）is a quence upstream the start codon in prokaryotic mRNA that can
ba pairs to a •UCCU•quence 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
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 conrvative amino terminal quence (13~36AA) that exists on
a newly synthesized cretory protein. It can direct this protein to a specific location
within the cell. It is subquently cleaved away by signal peptida; also called signal quence and targeting quence.
29.Operon（操纵子）: Bacteria have a simple general mechanism for coordinating the regulation of genes
who products are involved in related process: the genes are clustered on the chromosome and t
ranscribed together. Most prokaryotic mRNAs are polycistronic. The single promoter requi red 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 quences 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.Houkeeping gene（管家基因）Genes that are expresd at a fairly consistent level throughout the cell
cycle and from tissue to tissue. Usually involved in routine cellular metabolism. Often ud 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
quences to control gene expression. The properties of different trans-acting factors:
subunits of RNA polymera
bind to RNA Polymera to stabilize the initiation complex
bind to all promoters at specific quences but not to RNA Polymera (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 quences in the vicinity of the structural portion of a gene
that are required for gene expression. The properties of different cis-acting elements:
contain short connsus quences
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 respon
can be located in a promoter or an enhancer
assumed that a specific protein binds to the element and the prence of that protein is development
ally regulated
33.Southern blotting：Genomic DNA (from tissues or cells) are cut by RE, parated by gel
electrophoresis and denatured in solution, then transferred to a nitrocellulo membrane for detecting specific DNA quence by hybridization to a labeled probe. It can be ud 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 parated by gel electrophoresis and
denatured in solution, then transferred to a nitrocellulo membrane for detecting specific quence by hybridization to a labeled probe. It can be ud 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 parated by PAGE electrophoresis, then electro-transferred to NC
membrane. The proteins on NC membrane hybridize with a specific antibody (1st antibody ), then th
e target protein binding with antibody is detected with a labeled condary antibody (2nd antibody).
Also called immunoblotting. It can be ud to detect the specific protein, mi-quantify specific protein, etc.
36.PBlotting technique（印迹）:Transfer (blot) biological macromolecules parated in the gel and fix them
to nitrocellulo/nylon membrane by diffusion, electro-transferring or vacuum absorption, then detect
