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Mutations �Objective 7: Describe how mutations occur and the various types.� �Students will be able to:� 1) Describe the different types of chromosomal, frameshift, and point mutations.�2)Describe what a mutation is and what a mutagen does.�3) Identify examples of mutagens.

General High School Biology

Mr. Walker

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Genetic Changes

  • A mutation is any change to the DNA sequence.
    • Chromosomal mutations
    • Frameshift mutations
    • Point mutations
  • Only mutations in sex cells can be transmitted to offspring.
    • Potentially can produce new species

2)Describe what a mutation is and what a mutagen does.

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Chromosomal mutations

  • Deletions: When part of a chromosome is left out.
  • Insertion: When part of a chromatid breaks off and attaches to its sister chromatid
  • Inversion: When part of a chromosome breaks off and reattaches backwards

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  • Translocation: When part of one chromosome breaks off and is added to a different chromosome.
  • Chromosomal mutations are very common in plants
  • Sometimes homologous chromosomes don’t separate properly, this is called nondisjunction.

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Frameshift mutations

  • A mutation in which a single base is added to or deleted from DNA

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  • THE DOG BIT THE CAT
  • THE DOB ITT HEC AT

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Point mutations

  • A change in a single base pair in DNA

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  • THE DOG BIT THE CAT
  • THE DOG BIT THE CAR

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  • Example: Tay Sachs dz

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Causes of mutations

  • Mutagens are any agent which can cause a change in DNA.
    • Radiation
    • X-rays
    • UV light
    • Chemicals like asbestos, benzene, formaldehyde
  • Mutations can also occur each time our cells replicate our DNA and divide.

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2)Describe what a mutation is and what a mutagen does.

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Are �mutations �bad?

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Are mutations bad?

  • It depends
    • If the change causes disease (Dz). For example….. cancer
    • If the change allows the organism to be faster, stronger, smarter?
      • EVOLUTION BABY!