Mutations

• What is a mutation?


  changes in the genome with either no protein being expressed or an altered protein
• What is a single gene mutation?


  a mutation which only affects a single DNA nucleotide
• What is a chromosome mutation?


  change to one or more whole chromosomes
• Which single gene mutations are point mutations?


  only substitution
• Which single gene mutations are Frame-shift mutations


  insertion and deletion
• What is a point mutation


  When there is a change that only affects one codon
• What is a missense mutation?


  It changes the codon so that a different amino acid is produced

  it also changes the shape therefore the protein cannot carry out its function

  it is mostly silent changes
• what is a nonsense mutation?


  it changes the codon from an amino acid to a stop codon

  it produces a shorter protein

  it generally produces a non-functional or altered functional protein
• What is a Splice-Site mutation?


  it affects the boundaries between introns and exons.

  It can prevent splicing at that site

  A completely different protein is produced
• What is a frameshift mutation?


  This happens in insertion and deletions.

  When the codons are read at the ribosome, the codon reading frame is shifted by one codon, which means completely different amino acids are coded and results in a non functional protein as after the mutation every codon is affected.
• What is a chromosome structure mutation?


  Alterations that affect a whole chromosome and whole genes
• How do Chromosome mutations occur?


  they result from errors in cell division which causes a section of the chromosome to break off, be duplicated or move to another chromosome
• What are the types of Chromosome mutations?


  Deletion- a gene is removed

  Translocation- genes break off and attach to non- homologous partner

  duplication- genes are copied and inserted

  inversion- genes are reversed
• What is a mutation?


  rare, random changes in genetic material and can be inherited
• What are potential causes of mutations?

  ionising radiation- gamma rays, x rays, UV rays

  chemical mutagens- tar from cigarettes
• What do mutations do to your phenotype?


  They might change your phenotype or be silent or cause a genetic disease like cystic fibrosis
• What do mutations do to your phenotype?

  They might change your phenotype or be silent or cause a genetic disease like cystic fibrosis.