Realize that eukaryotes require the activity of telomerase to complete the synthesis of their linear chromosomes. The Semiconservative Nature of DNA Replication One property of the genetic material necessary for its function is the ability to replicate (reproduce) itself. After it was established that DNA is the genetic material, attention turned toward how DNA was replicating in living organisms. The Watson-Crick model of DNA structure (as outlined in the module on nucleic acids) suggested a possible mechanism for replication of DNA molecules. The nature of base pairing meant that if the two strands of a DNA molecule were separated, they could each serve as a template for the creation of a complementary strand by bringing in individual nucleotides to base pair with their complementary base on the template, and joining the new nucleotides together.
In addition, diseases such as Huntington’s disease, breast cancer, and muscular dystrophy are presently being screened for in humans (Jaroff, 1996). How researchers are able to screen for genes New developments have given researchers the ability to decipher the genetic code of organisms. Some of the techniques that researchers use are RFLP (restriction fragment length polymorphism) analysis and DNA probes. RFLP analysis utilizes enzymes from bacteria that are thought to be used as defense mechanisms against invading viral DNA. The enzymes fragment foreign DNA at specific locations depending on the base sequence (Griffiths, 1996).
A human DNA, in which biologists have identified and isolated the gene of interest using probes or antibodies, will then be chosen. This gene of interest is incorporated into the plasmid cuts. These new plasmids are mixed with, and taken up by bacterial cells under suitable conditions. As these bacterial cells reproduce, the plasmids containing the gene of interest will be copied, and transferred to the bacterial progenies. Genes are segments of chromosomes that code for specific polypeptide or RNA molecules.
The enzyme hilcase unwinds the two strands of DNA and little proteins attach to each side to keep them separated. From there another part of DNA called polymerase, attaches new nucleotides to match the existing one. After the new nucleotides are added, then they are recheck by the polymerase to make sure that they are right. Lastly, the DNA ligase enzyme completes and creates the continuous strand of DNA. This process is so delicate and has many chances to go wrong .
By natural breeding genes are passed down to offspring by the parents however, with new technology scientists are able to identify an individual gene and insert it into another organism which will then carry the trait of that gene. This alters the DNA. The extraction of the gene is done by physical and chemical methods The process of moving a gene from one molecule to another molecule is called cloning. In the cloning process a fragment of DNA, containing a gene is cloned into a vector where it is grown in large quantities and manipulated in a variety of ways. The most common vectors are bacterial plasmids but viruses and self-replicating units in eukaryotic cells are also employed as vectors.
The enzyme DNA helicase unwinds DNA at the replication fork. Proteins temporarily bind to each side of the strand to keep them separate. The enzyme gyrase moves ahead of the fork and reduces the torque caused by the replication fork by making a break in one segment of the strand, which it then synthesizes RNA primer for the binding of DNA nucleotides. Next the DNA strand is elongated by enzymes polymerase. Some of the DNA polymerase will synthesize replication and the others are involved with DNA repair.
It is that each of these individual processes carries much importance. DNA replication is important in the life of a cell, more so the division, because when a cell divides both of the daughter cells need identical DNA to function properly. PCR is important in that it allows amplification of DNA and isolation of DNA. PCR is also used to analyze DNA samples (used widely in crime scene investigation units) and allows scientists to work with DNA samples they previously could not. I will give a brief overview as to what the purpose of each process is, but I will focus more so on the individual differences and on the individual similarities between the two processes.
The Use of Recombinant DNA Technology Recombinant DNA technology is the technology of preparing recombinant DNA in vitro by cutting up DNA molecules and splicing together fragments from more than one organism. (1) This is the process of using recombinant DNA technology to enable the rapid production of human protein from a single gene of insulin. Firstly the single gene required must be isolated. This can be done three ways: Either by working backwards from the protein- Finding the amino acid sequence for the protein needed, the order of bases can be established using known genetic code. New DNA can be made from this sequence of bases resulting in artificial gene made from complementary DNA.
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DNA hybridization is the process of combining two complementary single stranded DNA or RNA molecules; they anneal using normal base pairing reactions. This can be used to detect certain sequences by using probes. The probes contain either radioactive of illuminesent materials thus it can be detected later. The probes anneal to the complementary single stranded DNA and RNA and can be visualised later by autoradiography or chemiluminescence. This allows the detection of certain gene sequences and allowing the Cystic Fibrosis gene to be pinpointed and accurately e... ... middle of paper ... ...are then designed to specifically down regulate the gene of interest.