Dna Replication Essay

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1. DNA Replication: * Begins at specific point; Origin of replication site. * Helicase unwinds & separates a portion of DNA into single strand sections. (breaks Hydrogen bonds) * Single-strand binding proteins react with and stabilize the sections. * DNA polymerase initiates replication process. It can only add new DNA nucleotides to a pre-existing chain of nucleotides. * Replication Begins; Primase assembles an RNA primer at the origin of replication site. * RNA Primer= short sequence of nucleotides + complementary(alongside) a small section of the DNA strand (initial) * DNA polymerase adds nucleotides to RNA primer, to start constructing new complementary strand. *ends a little before the end. * RNA primer = enzymatically removed + replaced with appropriate sequence of nucleotides. *2 complemetary strands = opposite directions (forked)+ polymerase only travels in 3’-5’ direction. * Strand 1. (going in 3’-5’ ) = replicated continuously towards unwinding & separating portion of DNA molecule * Strand 2. = Replicates discontinuously by breaking up into Okazaki fragments (each requires separate RNA primer.) * RNA primers replaced with appropriate DNA nucleotides and individual fragments bond together into a continuous complementary strand. 2. Central Dogma of Molecular Genetics/Biology: * James Watson; DNA RNAPROTEIN * Francis Crick named it C.D.M.G. * Dogma=Truth/belief * One gene – one polypeptide * Polypeptide: Non-functioning string of amino acids. * Protein: folded chain of amino-acids 3. PROTEIN SYNTHESIS: Transfer of DNA’s code into RNA and then RNA’s code to protein. Two phases: * Transcription: DNA RNA * Translation: RNA Protein 4. TRANSCRIPTION: * Initiation- The sense/ coding strand ha the particular gene which provides info to make a polypeptide. The

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