Molecular biology

1. 1. Operon
Operon means to operate . It is made up of a cluster of several structural genes arranged under a common operator and
regulated by common operator, function together in regulation
Eg Lac operon , Trptophan operon
2. Signal Transduction
The overall biochemical process of converting extracellular signals into intracellular response , as well as all the individual
steps in the process
Steps reception , transduction , response , termination
3. Cloning
means making copies of the gene, all identical to the original one. It can be original copy of gene=wild type or can be altered
version=mutant. It requires DNA ligase and restriction endonuclease
4. Oncogene
These genes code for proteins that are capable of stimulating cell growth and division.
In normal tissues and organisms, such growth- stimulating proteins are regulated, so that growth is appropriately limited.
However, changes/mutation in these genes may result in loss of growth regulation, leading to uncontrolled cell proliferation
and tumor development.
These changed genes are known as oncogenes, because they induce the oncogenic state — cancer.
Oncogenes are dominant, because a
change/mutation of only one of the cell’s two copies of that gene can lead to tumor formation.

2. 5. Chromatin remodeling
Dynamic transcription-associated structural changes of chromatin to allow access of condensed genomic DNA to the regulatory transcription machinery
proteins, and thereby control gene expression.
Transcriptionally inactive heterochromatin vs active euchromatin
Enzymatic modifications of histones and DNA
ATP-dependent chromatin remodeling Eg, SWI/SNF
6. Cis-acting elements
A region that regulates gene expression is locate up or downstream of a gene transcription site.
Cis-acting elements
The cis-acting elements are DNA fragments.
There are cis-acting elements in the flanking or the introns of eukaryotic gene.
The cis-acting elements include promoter, enhancer,silencer, insulator and so on.
7. Plamid
Naturally occurring extrachromosomalDNA mostly in prokaryotes.
Double-stranded, circular DNA, capableof automatically replicating in a hostcell.
Size: 1kb to over 200 kb;one-thousands copies/cell
Often carry genes that may benefit thesurvival of the organism.
Artificially constructed plasmids: important toolsin genetics and biotechnologylabs
Used to clone DNA fragments of up to15kb
8. DNA variation
Genetic variation is a term used to describe the variation in the DNA sequence in each of our genomes. Genetic variation is what makes us all unique,
whether in terms of hair colour, skin colour or even the shape of our faces.

3. 9. ESC
embryonic stem cells with pluripotency Or are pluripotent, self-renewing cells, which are derived from the inner cell mass (ICM) of the
developing blastocyst, and can develop almost all cell lineages in a body organism
10 Secondary messenger
small molecules that transfer information within the cells, relaying and often amplifying the signal of 1st messenger
Ca2+, cAMP,cGMP,DAG, IP3, Ceramide
Common properties:
coupled downstream to kinasecascades
synthesized and degraded by enzymes or ionchannels.
some (such as Ca2+) can be stored in special organelles and quickly released when needed.
production/release and destruction is localized, enabling the cellto limit space and time of signalactivity.
11 . siRISC
(RNA-induced silencing complex) is a multi-protein complex that incorporates one strand of siRNA or miRNA ORit is an active form of siRNA. It
uses siRNA or miRNA as a template strand to recognize the complementary strand of mRNA and activates RNAse then cleaves RNA.
12. Gene expression
The overall biochemical process of converting extracellular signals into intracellular response , as well as the individual steps in the process.
Reception , transduction , termination and response
13 Molecular/ Gene cloning
Molecular cloning is a set of techniques used to insert recombinant DNA from a prokaryotic or eukaryotic source into a replicating vehicle such
as plasmids or viral vectors. Cloning refers to making numerous copies of a DNA fragment of interest, such as a gene.

4. 14. Tumor suppressor gene
These genes code for proteins whosenormal function is to turn off cell growth.
A change/mutation in one of these growth- limiting genes may result in a protein product that has lost its growth limiting ability.
The normal forms of such genes have been shown to suppress tumor growth and are known as tumor suppressor genes or anti-oncogenes as
well.
Because both cellular copies of a tumor suppressor gene must be mutated to foil its growth-limiting action, these genes arerecessive in nature.
15. Imprinted gene
Genes which have especially been modified with DNA methylation, play essential roles in the growth and development of the fetus, as well as in post-
natal gene expression behavior and metabolism, which exhibit tissue-specific and temporal-specific imprinting patterns.
16. PMF
9The data of the characteristic peptide mass derived from MS spectrum of a protein is called as Peptide Mass Fingerprint (PMF) , which is based on that
the each protein has its own unique mass spectrum (the collection of value m/z), referred as PMF, because of each AA, the protein constituent unit,
having its own unique m/z value. It is a technique for rapid identification of proteins. PMF = m/z (TOF) = Protein ID
17 . Hierarchical Human Genome BAC source library
Every single chromosome of human genome. Shotgun genome, >30 K BAC colonies (200kb)
18 Cell pluripotency
ability to form all lineages of body (adult fertility and gametogenesis > neurulation and cns development>heart-tube development > muscle
differentiation >thymocyte development )
19 Imprinted gene cluster
It can express the parent-of-origin protein-coding or noncoding transcripts in reciprocal exclusive manner. (paternal vs maternal, protein-coding vs non-
coding gene transcription).Each imprinted gene cluster is under the control of a discrete region termed as ICR (imprinting control region). (ICR to control
the imprinted)

5. 20 Transcription attenuation
A regulatory process in which transcription is initiated normally but is abruptly stopped before structural genes are transcribed.
A process of translation directly affect transcription of operon.
Regulated by [trptophan]
21. Ligand
substance that can specially bind to the receptor
22 CpG strand
CpG is shorthand for 5'—C—phosphate—G—3' , that is, cytosine and guanine separated by only one phosphate group; phosphate links any two nucleosides
together in DNA.
23 Rnase protection assay
The RNase protection assay is a highly sensitive technique developed to detect and measure the abundance of specific mRNAs in samples of total cellular RNA.
24 Necrosis
Necrosis is the death of body tissue. It occurs when too little blood flows to the tissue. This can be from injury, radiation, or chemicals. Necrosis cannot be
reversed. When large areas of tissue die due to a lack of blood supply, the condition is called gangrene
25 RNAi
RNA-Mediated Cascade Reactions Triggered by siRISC or miRISC the target regions are recognized thru RNA-RNA interaction ,Protein-Protein, RNA- Protein, or
RNA-DNA interaction. RNAi means that it is RNA-mediated cascade reactions that changes in the cellular behavior of gene expression. May involve in genome,
transcriptome and proteome.
26 EMSA
The interaction of proteins with DNA is central to the control of many cellular processes including DNA replication, recombination and repair, transcription, and
viral assembly. One important technique for studying gene regulation and determining protein–DNA interactions is the electrophoretic mobility shift assay
(EMSA).