Dna and Replication Essay

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DNA and Replication You pose an interesting question – There are different types of Human DNA – which there are various classifications, Chromosomal DNA and Mitochondrial DNA. There is also the DNA present from normal flora microorganisms such as bacteria, viruses, mites, etc. Some of this microorganism DNA may be significant, such as E.coli DNA in the gut or Staphylococcus DNA on the skin. You even have DNA present from viruses of bacteria such as phage DNA. Some human viruses may be present in blood cells such as EBV, CMV in nerve cells like herpes simplex 1, in skin cell like HPV (human papilloma virus) or integrated into the Human Chromosomal DNA such as various retroviruses, like human foamy virus, HTLV or HIV Within Chromosomal DNA there is DNA that codes for genes- exons (mRNA coding) and non coding regions called introns. There are regions of DNA within the introns that are called endogenous retroviruses – these regions have great similarity to retroviruses and may have disease implications. An Okazaki fragment is a relatively short fragment of DNA that is created by primase and Pol III along the lagging strand (see DNA replication). They are later removed by RNAse H, and the last ribonucleotide is removed by and synthesized by Pol I. The nick, or a broken phosphodiester bond remaining between the fragments is linked together by DNA ligase The replication fork is a structure which forms when DNA is ready to replicate itself. It is created by topoisomerase, which breaks the hydrogen bonds holding the two DNA strands together. The resulting structure has two branching "prongs", each one made up of a single strand of DNA. DNA polymerase then goes to work on creating new partners for the two strands by adding nucleotides. A primer is a nucleic acid strand (or related molecule) that serves as a

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