Mutations in DNA

• What is a mutation?

  A change in the DNA base sequence
• What causes mutations to occur in cells?

  Spontaneous changes during DNA duplication
• What are carcinogens?

  Harmful chemicals that increase mutation risk
• How do radiation types like x-rays affect mutations?

  They increase the risk of mutations occurring
• What is a gene?

  A section of DNA that codes for protein
• What is a triplet or codon?

  A group of 3 bases coding for amino acids
• What happens if a codon changes due to a mutation?

  The amino acid it codes for may change
• How does a mutation affect protein formation?

  It can change the sequence of amino acids
• What is the effect of a mutation on an enzyme's active site?

  It may change the shape, affecting function
• What is the common outcome of most mutations?

  They often have no significant effect
• What is non-coding DNA?

  DNA that doesn't code for proteins
• Why do we have so much non-coding DNA?

  Its function is not fully understood
• How does non-coding DNA affect gene expression?

  It can turn genes on or off
• What are the three specific types of mutations?

  Substitutions, insertions, and deletions
• What is a substitution mutation?

  One base is changed for another base
• Why are insertion mutations considered worse than substitutions?

  They shift all subsequent bases in the sequence
• What happens during a deletion mutation?

  One base is removed from the sequence
• How does a deletion mutation affect the DNA sequence?

  It shifts all subsequent bases to the left
• What are the consequences of mutations on proteins?

  • Change in amino acid sequence
  • Potential alteration of protein shape
  • Possible loss of enzyme function
  • Most mutations have minimal effects
• What is the relationship between mutations and gene expression?

  • Mutations can affect coding regions
  • Non-coding DNA can regulate gene expression
  • Some mutations have no impact on expression