Inducible Operon vs Repressible Operon
Genetic regulation is a process where certain proteins and other kinds
of stimuli tend to cause a cell to express genes or not express them.
The bacteria cell system is small system, but it carries out a lot of
activities and must do so economically and efficiently, therefore
actions of these genes must be regulated. There are two types of
regulatory systems: inducible and repressible
An operon is a cluster of genes that work together to form a
polycistronic mRNA. It consists of structural genes, a promoter
region, an operator region, and a regulatory gene. Structural genes
code for the enzymes themselves. RNA polymerase transcribes all of the
genes into a polycistronic mRNA. The promoter is the site where the
RNA polymerase binds to the DNA prior to beginning transcription. The
operator serves as the binding site for the protein called the
repressor. The regulatory gene encodes the repressor protein.
An inducible operon is an operon in which the presence of a key
metabolic substance induces transcription of the structural genes. One
example of an inducible operon is lac operon and the inducer of this
operon is lactose.
A repressible operon is an operon which always transcribes structural
genes unless a repressor is present. One example of a repressible
operon is trp operon and the co-repressor of this operon is
tryptophan.
Both lac operon and trp operon have similarities and differences
Similarities
1. Both lac operon and trp operon have structural genes with related
function are controlled by a single promoter/operator.
2. Both lac operon and trp operon have negative control regulation
system controlled by repressor. There is a regulatory gene in the
operon which encodes the repressor protein that attach to the operator
to prevent transcription.
Differences
1. In term of structure, the lac operon has three structural genes:
lacZ, lacY, and lacA. Whereas the trp operon has five structural
genes: trpE, trpD, trpC trpB and trpA.
2. In term of function, an inducible operon is generally involves in
The plasmids in lanes 3,4,8 and 9 have been digested using one restriction enzyme and had been cut at one restriction site, resulting in a linear molecule. Comparing lanes 3 and 4 to
...et light. If the LAA plate glows green under exposure to ultraviolet light, then we can conclude that our unknown insert piece of DNA would be the kan gene. If it does not glow green under exposure to ultraviolet light, then then we streak the colony from our LAA plate onto the LAC plate using a sterile glass spreader. When the LAC plate is dray, we place it upside down in the microfuge rack so that it can be incubated at 37 ºC. Incubation at 37 ºC will allow the transformed bacterial cells to grow. If we see bacterial growth on the LA plate containing chloramphenicol, we can conclude that our unknown insert piece of DNA would be the cat gene, since the cat gene is resistant to chloramphenicol. Afterwards, we then grab the microfuge tube labeled NP and repeat the aforementioned steps shown above pertaining to the LA plates. This would be considered our control.
"The Species of the Secondary Protein Structure. Virtual Chembook - Elmhurst College. Retrieved July 25, 2008, from http://www.cd http://www.elmhurst.edu/chm/vchembook/566secprotein.html Silk Road Foundation. n.d. - n.d. - n.d.
Therefore colonies containing the non-recombinant pUC19 plasmid have a functional lacz’ gene appear blue on the agar and colonies containing recombinant pUC19 would have a non-functional lacz’ gene due to insertional inactivation and appear white on the growing medium.
The expression of lac operon in each tube equals the amount of beta-galactosidase produced. Therefore, by looking at the amount of beta-galactosidase under different conditions collectively is a good way to understand the function of inducers and repressors in supervising the expression of lac operon and the control of gene expression generally.
The purpose of this experiment was to discover the specificity of the enzyme lactase to a spec...
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There are 4 main mechanisms of modification and regulation of gene expression; DNA methylation, Chromatin Remodeling (architecture), Histone Modification and RNAi (interference/interactions)
In this paper, I will negatively expose Walter Glannon’s position on the differentially between gene therapy and gene enhancement. His argument fails because gene therapy and genetic enhancement is morally impermissible because its manipulation and destruction of embryos shows disrespect for human life and discrimination against people with disabilities.
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Over the past few decades, advances in technology have allowed scientists to actively manipulate the genetic sequence of an organism through a process called 'genetic engineering'. Many believe that this is a technique which we should exploit and take full advantage of as, after all, it may be the key to curing many hereditary diseases such as heart disease and cancer. It may very well be the solution to overcoming evolutionary barriers and allow us to breed new species. However, if you consider the unknown consequences we may have to face as a result of our futile experimenting, you would find that messing with a system as intricate as nature for curiosity's sake is hardly justifiable.
...ons have high frequencies of lactase persistence and low frequencies of the T-13910 allele. Two SNP have been lined to lactase persistence in Saudi population, T/C-3712 and T/G-13915 (Enattah et. al, 2008). Both have been show to increase transcription of lactase in vitro (Enattah et. al, 2008).
Citation: Philips, T. (2008) Regulation of Transcription and gene expression in Eukaryotes. Nature Education 1(1)
Secondly the gene has to be cut from its DNA chain. Controlling this process are many restriction endonucleases (restriction enzymes). Each of these enzymes cut DNA at a different base sequence called a recognition sequence. The recognition sequence is 6 base pairs long. The restriction enzymes PstI cuts DNA horizontally and vertically to produce sticky ends.