1) Chloramphenicol is a type of protein synthesis inhibitor that binds to the 50S ribosomal subunit which can be harmful to certain bacteria, fortunately many bacteria have developed a resistance towards it by either closing off the outer membrane so that the antibiotic cannot enter at all or by developing certain genes that will act like a shield to the part of the bacteria the antibiotic is trying to get to. This resistance is vitally important because if the antibiotic were to bind to the cell, it would start growing on the bacteria causing it to eventually die.
For protection from inhibitors like chloramphenicol, bacterium could use antibiotic-resistance regulons in two different ways. One being under positive control, and the other being under negative control. If the bacterium’s regulons were inducible under the positive control, a protein would be developed. During translation, the protein would attach to the A site which would prevent the chloramphenicol from binding to the ribosome. This would not affect the cell translating the regular protein forming information needed for survival because of protein building.
On the other hand, for negative regulation the cell would have to recognize the antibiotic was there, and then close off the pores. In order to do this, the cell would need to have a protein that inhibits the expression of genes by binding to the operator. This protein is known as a repressor. This would allow the operator to take control of the operon in charge of the pores of the membrane and close them in order to keep the antibiotic out.
2) Without base pairing between nucleotides and the basis of a specific shape, processes like replication, transcription, translation and DNA repair would not be able to carry out their specific functions as efficiently as they could with it, and there would be more errors in the pairing of bases. Nucleotides are long chains (polymers) of chemical units (monomers) that make up nucleic acids, which make up DNA and RNA.
DNA is the information molecule of the cell. DNA’s capacity to store and transmit heritable information is very much dependent on interactions between nucleotide bases, and on the fact that some combinations of bases form stable links, while other combinations do not. The base pairs that form stable connections are called complementary bases.
One obvious reason for complementary base pairing is to minimise errors. For example, if a G and C pair and an A and T pair, but a G-T and G-A cannot pair then you're going to have preferential pairing between correct bases as opposed to pairing between incorrect bases, thereby minimising error.
Essentially, complementary base pairing is an error-free (in principle) system of matching, which therefore enables the building of DNA using a template manner where one strand will dictate the nature of the other strand. For example, if a T could pair with an A, G, or C, then you wouldn't be able to take one single strand of DNA and know which of those three matches. Or if a line of DNA that was ATTCG could be matched with any random combination, then you'd never be able to replicate it. However, because of complementary base pairing, then in replication you know that you've got to synthesise the new strand so that it reads the opposite and matches the other base (TAAGC). Matching strands is very important to transcription, replication, translation, and DNA repair because they all follow a system that needs exact matching in order to be successful.
The shape of DNA also plays a large role in all of the processes being executed correctly. DNA can replicate itself because of the way its double strands relate to one another. The purines and pyrimidines that join the two strands pair exclusively with only one other base, which ensures that when the DNA strands separate to replicate an exact copy is created. This can also be said for transcription, translation, and DNA repair being that they all require exact matching.
In certain cases, mutations can combine with the environment to produce adaptive advantages. Some common examples of beneficial mutations are those involved in bacterial antibiotic resistance, which enable the bacterium to survive exposure to various antibiotics.Bacteria also can undergo adaptive mutation; a phenomenon used by bacteria to survive very specific stressful conditions. Various mutations have also been found that enable bacteria to survive temporary exposure to high temperatures or starvation. Such mutations usually involve loss of certain sigma factors, reduction of DNA repair, or loss of specific regulatory controls.Each of these examples involves certain environmental conditions that make these mutations phenotypically beneficial.
3) When there is a Hfr X F- cross the DNA plasmid becomes linear while moving through the conjugation tube into the F- recipient that eventually breaks so that only a portion of the Hfr is transferred which causes the F- recipient to remain F-; on the contrary, in a F+ X F cross all of the DNA from the F+ donor is transferred into the F- cell causing the conjugation tube to dissolve and the F- recipient becomes F+.
The full genome sequence of the Escherichia coli is OFBAEMHRCXG. Both the polarity and the ori site of this particular sequence is dependent upon which part of the plasmid is being transferred. The shape of the plasmid also plays a large role in that determination since it can unravel clockwise or counterclockwise. Since the whole plasmid is unable to transfer completely, the F- donor will remain F-.
4) Through the process of transformation, operons are transferred as the DNA from the donor cell is passed along the recipient cell, which evolves by the transferred DNA mixing with the original DNA in a way that is beneficial to the cell.
In order for an operon to produce adaptive advantage to more than just one bacteria, the operon needs to be transferred to more than one bacteria. This can be done by the conjugation method. Operons start to evolve by only working in the new cell if the entire gene series is transferred or if the new cell has the needed material to complete the series correctly. If a specific operon is inserted into a new cell in a place where there used to be an operator and a promoter, a different function may be created. If the product operon is good for the cell it will prosper in the environment. Through conjugation, this operon mutation is then transferred into another cell therefore continuing the cycle.
Jada, H (2018). Micro. Afribary.com: Retrieved February 23, 2018, from http://dubz-by-dan.co.uk/works/micro-7684
Hunter, Jada. "Micro" Afribary.com. Afribary.com, 29 Jan. 2018, http://dubz-by-dan.co.uk/works/micro-7684 . Accessed 23 Feb. 2018.
Hunter, Jada. "Micro". Afribary.com, Afribary.com, 29 Jan. 2018. Web. 23 Feb. 2018. < http://dubz-by-dan.co.uk/works/micro-7684 >.
Hunter, Jada. "Micro" Afribary.com (2018). Accessed February 23, 2018. http://dubz-by-dan.co.uk/works/micro-7684