Primase Essays

Elizabeth Blackburn The work of Elizabeth Blackburn concerns the performance and production of telomeres, which are the ends of eukaryotic chromosomes. Telomerase specifies the sequence of telomeric DNA by using a short sequence of the telomerase RNA moiety as the guide for DNA synthesis. Therefore, telomeric DNA is a vital chromosomal component which is unusual as it is made by copying an RNA sequence; which is an extremely specialised, distinctive mechanism. Her goal is to grasp the role of telomerase

The 5 components are Helicase, Polymerase I, polymerase III, primase, ligase. Helicase: It is the enzyme that unwinds the DNA stands (separate the strands) by breaking the hydrogen bond between the nucleotide bases. It is used as template during DNA replication. Polymerase I: It removes the primer from the 5’ end of the leading strand and replaces it with DNA, at adjacent 3’ end and fill in with DNA nucleotides. Polymerase III: It continuously synthesises the leading strand, adding on to the primer

enzyme initiates the DNA process by unwinding the double helix. If it was missing, the DNA would not be able to replicate as the helix structure would not open. The next step of DNA Replication is the binding of RNA primase in the the initiation point of the 3'-5' parent chain. RNA primase can attract RNA nucleotides which bind to the DNA nucleotides of the 3'-5' strand due to the hydrogen bonds between the bases and also provide a starting point for DNA polymerases to extend from. Without it, the DNA

for the synthesis of the leading and lagging strands. There are 5 distinct polymerases involved in E. coli, however DNA polymerase III is mainly responsible for the DNA replication. In the synthesis of the leading strand the RNA primers produced by primase allow for the DNA polymerase III to begin synthesizing a complimentary daughter strand of DNA. Nucleotides are attached to the 3’ end of each primer in a 5’ to 3’ direction. This attachment is catalyzed by the DNA polymerase III. In reference specifically

from 4 nucleotide bases, using existing DNA as template. 7. new complementary nucleotide bases {A, C, G and T} to strand of DNA in 5 to 3 direction. This type of replication called continuous. Lagging strand: 5. Numerous RNA primer is made by primase enzyme and bind at various points along lagging strand. 6. Pieces of DNA called Okazaki fragment, is then added to lagging strand in 5 to 3 direction. 7. This sort of replication called discontinuous as Okazaki fragment will need to be joined up later

manner. To ensure that each sequence is replicated only once, additional mechanisms are in place that isn’t seen in simpler organisms. Lastly, eukaryotes also employ two distinct polymerases: polymerase alpha and polymerase delta. The former is a primase and polymerase in one. The latter is similar to polymerase III of E. coli and is the more processive enzyme of the

strands. The DNA single-stranded binding proteins is a type of protein that binds to the as a tetramer and makes the strand stable. DNA gyrase is an enzyme that catalyzes formations of negative supercoils that assist with the separation of the strands. Primase provides the need for a free 3’ hydroxyl group by being synthesized in the initiation sites. DNA ligase gets rid of any nicks by forming a covalent phosphodiester linkage form the 3’-hydroxyl and 5’-phosphate. Eukaryotes have longer chromosomes than

both eukaryotes and prokaryotes Each type of DNA polymerases works in the 5’ to 3’ direction. The DNA replication in both eukaryotes and prokaryotes requires RNA primer to initialize The synthesis of the RNA primer is done by the enzyme called primase The replication process in both eukaryotes and prokaryotes are bi-directional, progressing both ways Difference in DNA replication between eukaryotes and prokaryotes is summarize below (BiologyWise, 2018). Location Eukaryotes have nucleus

the energy dissipation. How helicase actually works is still unknown but there are recently three proposed models which include Plough-share model, rotary pump model and steric exclusion model(Ding and Liu, 2015). Once DNA strand unwound the RNA primase form primer to 3’end of new strand so that DNA polymerase easily held to the strand and add nucleotides to the strand which are already freely available in nucleus. The energy provided to DNA polymerase comes from breakage of bonding by helicase and

1.Make a diagram (or multiple diagrams) indicating the steps and the enzymes involved in DNA replication in Prokaryotes. In the diagram include the following labels: primase, RNA primer, DNA polymerase I & III, Helicase, ligase, Topoisomerase, Okazaki fragments, 3' and 5'ends, leading strand, lagging strand) Draw it in paper and upload a photo or scanned. According to the book page 268, DNA binds to oriC facilitating the initial strand separation. Then helicase opens the helix of DNA, proteins bind

DNA and RNA Introduction DNA and RNA are one of the most significant macromolecules in a cell. The transition of information from DNA to RNA and protein determines absolutely all features of a living cell: its size, shape, function and time of death. There are three main sequential mechanisms, by which this transferring of information occurs within a cell: DNA replication, transcription and translation. DNA Replication DNA is a double-stranded macromolecule, which consists of sugar (deoxyribose)

Telomerase Telomerase is a specialised ribonucleoprotein reverse transcriptase enzyme[1]. It carries its own RNA molecule. Telomerase is functional at the tips of chromosomes in areas known as telomeres. The main function of telomerase is to extend the 3' ends of DNA strands by adding 'TTAGGG' repeat sequences as it is not possible for DNA polymerase to replicate 3' ends. Elizabeth Blackburn (molecular biologist, co-discoverer of telomerase and co-winner of the 2009 Nobel Prize for Physiology or

this genetic material is made of four different bases which are guanine, thymine, cytosine and adenine. (1) Replication occurs when an enzyme called helicase uncoils into the double helix onto two intertwining strands. The second enzyme is called primase and basically what this does is it attaches a ‘primer’ to each of the strands and the third enzyme is called DNA polymerase and this attaches to the primer and adds new bases to form the new double helix. “Double helices are formed from two strands

Polymerase Chain Reaction (PCR) is a laboratory technique used in molecular biology to generate a small section of DNA or genes, PCR uses primers to amplify specific genomic DNA sequences with the help of special enzymes, PCR process uses short sequences of DNA and primers and selects specific chromosomes of DNA for replication. (McPherson and Møller, 2009) In addition, there are three main steps involve PCR process, first step of PCR is denaturing when DNA is heated to 90-95 degrees Celsius and

1st Amendment Wrangling There have been many supreme and district court cases that involve the first amendment. Your First Amendment rights are a heavily debated topic. Students, in particular, walk a very fine line regard to their free speech. Schools, students, and the federal government are still trying to figure out where they stand. Within this essay there are three main topics that I wish to cover; they are as follows Dress Code, Student Free Speech, and Internet Use. Every case within these