GCSE Biology (AQA)

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Mutations

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Inheritance, Variation and Evolution Reproduction

Mutations

3:23 Coding for Proteins
Spec 4.6.1.5
Previous Protein Synthesis Next Coding & Non-Coding DNA
  • Mutations cause changes in DNA structure.
  • Mutations can change the phenotype, though rarely.
  • An example of a phenotype-changing mutation is heterochromia, which results in two different eye colors.
  • Mutations occur naturally and can be triggered by radiation or toxic substances.
  • Common sources of such mutations include gamma rays, x-rays, UV rays, and toxic substances in cigarette smoke.
  • Mutations affect the sequence of bases in DNA, altering the genetic code.
  • Most mutations do not change the proteins produced by DNA.
  • Serious mutations, like base insertions or deletions, can alter the entire amino acid sequence of a protein.
  • Changes in the amino acid sequence can lead to proteins with different shapes and functions.
  • This can affect the strength of structural proteins like collagen or the activity of enzymes by altering their active sites.
  • Mutations are sometimes referred to as genetic variants because they can result in different proteins being produced.

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