Neuron13
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Can someone help me "Outline the problems that occur with DNA Replication and what the consequences of this might be"
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Jpw1097
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(Original post by Neuron13)
Can someone help me "Outline the problems that occur with DNA Replication and what the consequences of this might be"
DNA replication isn't perfect. DNA polymerase can make mistakes when it is building the new DNA strand and insert the wrong nucleotide which alters the DNA base sequence - ie a mutation occurs. DNA polymerase has a proofreading mechanism. When it 'realises' it has made a mistake, it uses its 3' to 5' exonuclease activity to remove the incorrect nucleotide and insert the correct nucleotide. However, even this proofreading mechanism isn't 100% efficient and some errors are not corrected by DNA polymerase.

There are proteins which track along DNA in search of mutations. Upon encountering a mutation, these proteins activate DNA repair mechanisms which correct the mistake. As with anything, this isn't 100% efficient and some mutations remain. Cells that have damaged DNA could potentially become cancerous. There are a few ways in which this can be prevented: the cell can undergo programmed cell death (apoptosis) or the cell can undergo cellular senescence, an irreversible process whereby a cell can no longer undergo mitosis. If all of these mechanisms fail, a cell could become cancerous.

Hopefully this helps.
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