Carcinogenesis

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Carcinogenesis

• Review
• Whats the basic cell structure?
• Whats DNA and where is it located?
• How does a mutation initiate cancer?

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Initiation of cancer
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Cell Division

• Multi-step process
• Regulated by environment and genes
• G1- cell increases in size
• S- DNA copied (2 copies present in cell)
• G2-
• M- Cell divides

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Cell Division
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Questions

• How is the cell cycle controlled?
• In which step of the cell cycle would mutations
  arise?

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Within our genes..

• Regulatory mechanisms to control growth and
  division
• Proto-oncogene stimulate cell division
• Tumor suppressor genes inhibit division
• Balance of two sets of genes- keeps cells
  dividing normally

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Regulatory Genes
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Mutations

• Mutations- changes in DNA sequences
• Point mutations- one positions altered
• Insertions- introduction of new sequences
• Deletions- removal of sequences
• Mutations are particularly problematic in
  regulatory genes

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How do mutation arise?

• Genetic
• Carcinogens
• Spontaneous mutations in DNA replication

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Mutations
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Detrimental mutations

• Mutations that affect regulatory genes are
  particularly detrimental
• Cell loses ability to control cell division

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Mutations movie II