GENE

• WHAT IS A GENE MUTATION?

  change in base sequence of DNA
• WHEN DOES A GENE MUTATION OCCUR?

  randomly in DNA replication
• WHEN IS A GENE MUTATION MORE LIKELY TO OCCUR?

  if exposed to mutagenic agents
• WHAT ARE EXAMPLES OF MUTAGENIC AGENTS?

  • high energy radiation (UV light)
  • ionising radiation (gamma rays/ X-rays)
  • chemicals (carcinogens)
• TWO TYPES OF GENE MUTATION?

  base substitution, base deletion
• WHAT USUALLY HAPPENS IN BASE SUBSTITUTION?

  no impact as new codon may code for same AA

  -> genetic code is degenerate
• WHAT USUALLY HAPPENS IN BASE DELETION?

  frameshift as all subsequent codons are changed