Mutations

• What is a mutation?

  A change in the DNA base sequence
• What can cause mutations in DNA?

  Carcinogens and certain types of radiation
• When do mutations commonly occur?

  During DNA duplication before cell division
• Do carcinogens always cause mutations?

  No, they increase the risk of mutations
• What is a codon?

  A group of 3 bases coding for an amino acid
• What happens if a codon is mutated?

  The amino acid it codes for may change
• How can a mutation affect protein function?

  It can change the protein's shape or function
• What is the effect of a mutation on an enzyme?

  It may change the enzyme's active site
• Why do most mutations have no significant effect?

  They often affect proteins only slightly
• What is non-coding DNA?

  DNA that doesn't code for protein
• What role does some non-coding DNA play?

  It helps in the expression of genes
• Why might a nerve cell not produce hemoglobin?

  The gene for hemoglobin is switched off
• What are the three specific types of mutations?

  • Substitutions
  • Insertions
  • Deletions
• What is a substitution mutation?

  One base is changed for another base
• How does an insertion mutation affect the DNA sequence?

  An extra base is added, shifting others
• Why are insertion mutations considered worse than substitutions?

  They shift all subsequent bases along
• What happens during a deletion mutation?

  A base is removed, shifting others left
• What is the result of a deletion mutation?

  All subsequent codons are altered