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    The document describes the key enzymes involved in DNA replication in prokaryotes and eukaryotes. It lists the main enzymes for each, including helicase, primase, DNA polymerase, ligase, exonuclease, telomerase and single-strand binding proteins. It also compares prokaryotic and eukaryotic replication, noting differences such as location (cytoplasm vs nucleus), number of origins of replication, and replication speed. The main replication enzymes in eukaryotes are DNA polymerase alpha, delta and epsilon, while in prokaryotes they are DNA polymerase I, II and III.

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    New Microsoft Word Document

    Uploaded by

    Anonymous Ne3gPmoI
    377 views5 pages
    The document describes the key enzymes involved in DNA replication in prokaryotes and eukaryotes. It lists the main enzymes for each, including helicase, primase, DNA polymerase, ligase, exonuclease, telomerase and single-strand binding proteins. It also compares prokaryotic and eukaryotic replication, noting differences such as location (cytoplasm vs nucleus), number of origins of replication, and replication speed. The main replication enzymes in eukaryotes are DNA polymerase alpha, delta and epsilon, while in prokaryotes they are DNA polymerase I, II and III.

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    The document describes the key enzymes involved in DNA replication in prokaryotes and eukaryotes. It lists the main enzymes for each, including helicase, primase, DNA polymerase, ligase, exonuclease, telomerase and single-strand binding proteins. It also compares prokaryotic and eukaryotic replication, noting differences such as location (cytoplasm vs nucleus), number of origins of replication, and replication speed. The main replication enzymes in eukaryotes are DNA polymerase alpha, delta and epsilon, while in prokaryotes they are DNA polymerase I, II and III.

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    377 views5 pages

    New Microsoft Word Document

    Uploaded by

    Anonymous Ne3gPmoI
    The document describes the key enzymes involved in DNA replication in prokaryotes and eukaryotes. It lists the main enzymes for each, including helicase, primase, DNA polymerase, ligase, exonuclease, telomerase and single-strand binding proteins. It also compares prokaryotic and eukaryotic replication, noting differences such as location (cytoplasm vs nucleus), number of origins of replication, and replication speed. The main replication enzymes in eukaryotes are DNA polymerase alpha, delta and epsilon, while in prokaryotes they are DNA polymerase I, II and III.

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    The key enzymes and their functions in DNA replication include helicase, primase, DNA polymerase, ligase and more.

    Prokaryotic replication occurs in the cytoplasm with a single origin of replication whereas eukaryotic replication occurs in the nucleus with multiple origins of replication. Prokaryotes have one replication fork whereas eukaryotes have multiple replication forks.

    The main eukaryotic DNA replication enzymes are DNA polymerase α, δ and ε. DNA polymerase α initiates replication, δ completes lagging strand synthesis and ε synthesizes the leading strand.

    :Enzymes of DNA Replication:

    Helicase:

    Helicase enzyme function is unwounds a portion of the DNA Double Helix.


    RNA Primase:

    RNA Primase enzyme function is attaches RNA primers to the replicating strands.
    DNA Polymerase delta ():
    Binds to the 5' - 3' strand in order to bring nucleotides and create the daughter leading strand.
    DNA Polymerase epsilon ():
    Binds to the 3' - 5' strand in order to create discontinuous segments starting from different RNA
    primers.
    Exonuclease (DNA Polymerase I):
    Exonuclease DNA Polymerase I enzyme function is finds and removes the RNA Primers.
    DNA Ligase:
    Adds phosphate in the remaining gaps of the phosphate sugar backbone.
    Nucleases:
    Remove wrong nucleotides from the daughter strand.

    Telomerase:
    Catalyzes the lengthening of telomeres, the enzyme includes a molecule of RNA that serves as a
    template for new telomere segments.

    Single Strand Binding Proteins:

    Responsible for holding the replication fork of DNA open while polymerases read the templates
    and prepare for synthesis.
    :Difference Between Prokaryotic and Eukaryotic DNA Replication:

    Prokaryotic DNA Replication Eukaryotic DNA replication

    Occurs inside the cytoplasm Occurs inside the nucleus

    Only one origin of replication per molecule Have many origins of replication in each
    of DNA chromosome

    Origin of replication is about 100-200 or Each origin of replication is formed of about 150
    more nucleotides in length nucleotides

    Replication occurs at one point in each Replication occurs at several points


    chromosome simultaneously in each chromosome

    Only one replication fork is formed Multiple replication forks are formed
    simultaneously in each chromosome

    Only have one origin of replication Has multiple origins of replication

    Initiation is carried out by protein DnaA and Initiation is carried out by the Origin
    DnaB Recognition Complex

    Topoisomerase is needed Topoisomerase is needed

    Replication is very rapid Replication is very slow


    :Eukaryotic DNA Replication Enzymes List:

    ENZYMES FUNCTION

    DNA polymerase Contains primase activity that is necessary to initiate DNA


    synthesis on both leading and lagging strands.

    DNA polymerase Required to complete synthesis of Okazaki fragments on the


    lagging strand that have been started by DNA polymerase .

    DNA polymerase The leading strand polymerase. Synthesizes DNA at the replication
    fork. Binds early at origins via Dbp11 and needed to load DNA
    polymerase .
    :Prokaryotic DNA Replication Enzymes List:

    Enzymes Function
    DNA polymerase I Exonuclease activity removes RNA primer and replaces newly
    synthesized DNA.

    DNA polymerase II Polymerase II is a DNA repair enzyme with a 3 to 5 exonuclease


    activity.

    DNA polymerase III To allow for processing of both the leading and lagging DNA
    strands.

    Helicase Open the DNA helix by breaking hydrogen bonds between the
    nitrogenous base.

    Primase Start the replication.

    Ligase Seals gaps between the okazaki fragments to create one continuous
    DNA strands.

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