Download Unit 6 Notes: Mutations DNA Mutations Mutations

Unit 6 Notes:
Mutations
DNA Mutations
• Mutations: Any change in the sequence of
nitrogenous bases of DNA.
• Causes:
– Mutagens = factors that change chemical nature of
DNA
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Cell errors
Chemical / UV light exposure
Radioactive substances
X-rays
Types of Mutations
• Point mutation: Change 1 base along DNA sequence.
– Substitution  Replace 1 base with a different one.
Results of Point Mutations
• Missense: Mutation changes the type of protein made.
• Nonsense: Mutation causes premature stop in
translation.
• Silent: Changes bases, but has no effect on protein made.
Types of Mutations
• Frameshift mutation: Any Insertion or Deletion mutations
which shift the bases, changing the amino acid sequence.
– Insertion  Add 1 extra base
– Deletion  Remove 1 base
Example Diseases Cause by Mutations
• Color blindness  Point mutation
• Hemophilia  Point mutation
– Blood doesn’t clot, lacks clotting proteins
• Sickle-cell disease  Point mutation
Mutations – Visual Learning
• https://www.youtube.com/watch?v=GieZ3pk9
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• Http://educationportal.com/academy/lesson/how-pointmutations-insertions-and-deletions-affectdna.html
• https://www.youtube.com/watch?v=0wrNxCG
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