8.5 Translation Set up Cornell Notes on pg. 11 Topic: 8.7 Mutations Essential Question: 1.Explain...

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)