2.2.4

Cancer

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Cancer

Cancer comprises many different diseases caused by a common mechanism: uncontrolled cell growth.

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Gene mutations

  • Although the cell cycle is tightly controlled by genes, errors do happen.
  • Changes to the DNA nucleotide sequence can cause a gene mutation.
  • A gene mutation may give rise to a faulty protein.
  • The change in the cell that results from the malformed protein may allow subsequent mistakes to happen more often.
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Uncontrolled cell division

  • Small uncorrected errors are passed from the parent cell to the daughter cells.
  • As each generation produces more non-functional proteins from uncorrected DNA damage, mutations accumulate.
  • This can lead to uncontrolled growth of the mutated cells. This creates a tumour.

Treatment of Cancer

Cancer is caused when the cell cycle is not properly controlled. Cancer can be treated by targeting the phases of the cell cycle.

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G1

  • G1 is a phase in interphase that produces new organelles and causes the cells to grow in size.
  • If the genes that encode the enzymes involved in this process are mutated, the cell cycle can be altered.
  • Drugs can be targeted to inhibit G1 and treat cancerous cells.
  • The drugs halt the cell cycle and kill the cells.
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S phase

  • S phase is the stage in interphase that causes DNA to replicate.
  • Errors in DNA replication can lead to the development of tumours.
  • Drugs can be targeted to damage the DNA and kill the cells to prevent the spread of a tumour.

Jump to other topics

1Biological Molecules

2Cells

3Substance Exchange

4Genetic Information & Variation

5Energy Transfers (A2 only)

6Responding to Change (A2 only)

7Genetics & Ecosystems (A2 only)

8The Control of Gene Expression (A2 only)

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