MUTATION AND PROTEINS

WARM-UP

• Finish the Pre-lab on your Enzyme Lab handout.

• Announcements• - 8 days until DNA Exam• - US Geological Survey Paid Internship Program• - Guest Speaker Tomorrow• - Return the UV Light Box – 5 people• - Dissecting Scopes from Jay Vavra – 2 people

Mutations

Mutations are changes in the genetic material of a cell

Mutations Point mutations are changes in one base pair of a gene

a. What would the series of nucleotides in mRNA transcribed from this strand be?

AUG UGG GAG CAU UGA

b. List the codons from the mRNA coded for by this series of DNA?

c. If the sequence of DNA nucleotides above is a complete gene that codes for a protein, what are the amino acids that make this protein?

Start(Met) Trp Glu His Stop

Mutations• How are the proteins for each DNA sequence different?

They’ re not• This is an example of point mutation called a silent

mutation

Mutations• What would the series of nucleotides in mRNA transcribed from this

strand be?

AUG UGG GUA CAU UGA•  List the codons from the mRNA coded for by this series of DNA?• If the sequence of DNA nucleotides above is a complete gene that

codes for a protein, what are the amino acids that make this protein?

Start(Met) Trp Val His Stop• How are the proteins for each DNA sequence different?

Glu into Val• This is an example of a type of point mutation called a missense• The last type of point mutation is called a nonsense

Sickle Cell Anemia:

http://www.pbs.org/wgbh/evolution/library/01/2/l_012_02.html

Mutations A frame shift mutation is when a certain number of nucleotides are inserted or deleted in the reading frame of a gene

…what would the RNA sequence of the original strand and the mutated strand be?

AUGGGGAACAUUGA

If the sequence of DNA nucleotides above is a complete gene that codes for a protein, what are the amino acids that make this protein?

Start-Gly-Asn-Ile- vs. Start Trp Glu His Stop

How are the proteins for each DNA sequence different?

Every single protein is different and there is no stop codon

This type of frameshift mutation is called a(n) deletion

How do Mutations occur

DNA replication

Mutagens

can be physical or chemical

- physical: UV or Xrays

- chemical: imidazole or EtBr (ethidium bromide)