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8.5 Translation•Set up Cornell Notes on pg. 11
•Topic: 8.7 Mutations
•Essential Question:
1.Explain why a frameshift mutation has a greater effect than do point mutations.
2.1 Atoms, Ions, and Molecules
8.7 Mutations
1. Explain why a frameshift mutation has a greater effect than do point mutations.
KEY CONCEPT Mutations are changes in DNA that may or may not affect phenotype
8.5 Translation
• P.10Points to Ponder
Point Mutation
Frameshift Mutation
8.7 Mutations
Points to Ponder (Top of p. 10)
• What do you think of when you hear the word “mutation”?
–Are they always bad?
–Give me an example
8.7 Mutations
Mutations?
8.7 Mutations
Mutations (1m13s)
8.7 Mutations
KEY CONCEPT Mutations are changes in DNA that may or may not affect phenotype.
8.7 Mutations
• Not all mutations are bad, but most do have negative effects
What mutations do you notice here? Why might these be problematic?
8.7 Mutations
• A mutation is a change in an organism’s DNA.– Many kinds of mutations can occur, especially during
replication.
8.7 Mutations
GENE MUTATIONS
1) A point mutation substitutes one nucleotide for another.
GAT CTC
GAT CACDraw a picture: middle of p. 10
8.7 Mutations
Example of a point mutation
• Sickle cell anemia
8.7 Mutations
2) A frameshift mutation inserts or deletes a nucleotide in the DNA sequence.
THE CAT ATE THE RAT
THC ATA TET HER AT….
Draw a picture: bottom of p. 10
8.7 Mutations
• Example of a frame shift mutation:
• Tay–Sachs disease – Develops @ around 6 months of age– Nerves start deteriorating– Child becomes blind, deaf, and unable to swallow– Death usually occurs before the 4th year
8.7 Mutations
Chromosomal mutations – affect many genes– may occur during crossing over
8.7 Mutations
Mutations may or may not affect phenotype (looks).
• Chromosomal mutations tend to have a big effect. • Some gene mutations change phenotype.
Ex: down syndrome
8.7 Mutations
• Some gene mutations do not affect phenotype.
– A mutation may be silent.
blockage
no blockage
Ex: Cystic Fibrosis- caused by a deletion
8.7 Mutations
• Mutations in body cells do not affect offspring.
Ex:Lung cancerSkin cancer
8.7 Mutations
• Mutations in sex cells can be harmful or beneficial to offspring.
• Natural selection often removes mutant alleles from a population
8.7 Mutations
Beneficial mutations CCR5 32 is a deletion thought to resist the bubonic and pneumonic plague as well as HIV
Mutations that cause resistance to antibiotics
8.7 Mutations
• Chang and Eng Bunker• Born in 1811• Married sisters• Had 21 children between
them • In modern times, they
could have easily been separated
• Died on the same day in 1874
• Chang contracted Pneumonia and died in his sleep- Eng refused to be separated from his dead twin and died several hours later.
Conjoined Twins
8.7 Mutations
Mutations caused by Mutagens
• Radiation
8.7 Mutations
Mutations 2 (5m37s)