Mutation

• What is a mutation?

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

  Spontaneous changes during DNA duplication
• What are carcinogens?

  Harmful chemicals that increase mutation risk
• Name two types of radiation that can increase mutation risk.

  X-rays and gamma rays
• Do carcinogens always cause mutations?

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

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

  A group of 3 bases coding for amino acids
• How many different amino acids can codons code for?

  20 different amino acids
• What happens if a mutation changes a codon?

  The amino acid coded by that codon may change
• How can a mutation affect protein function?

  It can change the protein's shape or function
• What is an enzyme's active site?

  The region where substrates bind to the enzyme
• Why do most mutations have no significant effect?

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

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

  It helps regulate gene expression
• What is a substitution mutation?

  When one base is changed for another
• Why are insertion mutations considered worse than substitution mutations?

  They shift all subsequent bases in the sequence
• What happens during an insertion mutation?

  An extra base is added to the DNA sequence
• What is a deletion mutation?

  When 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 three specific types of mutations?

  • Substitution mutations
  • Insertion mutations
  • Deletion mutations
• What are the consequences of mutations on proteins?

  • Change in amino acid sequence
  • Altered protein shape or function
  • Potential loss of enzyme activity
• How does gene expression differ in nerve cells compared to red blood cells?

  • Nerve cells do not express hemoglobin gene
  • Hemoglobin gene is switched off in nerve cells