1. Mutations

2. ex: Chemicals, high temperatures, UV light, radiation
General Information
 Mutation: Mistake in the DNA.
 Can be random or caused by mutagens.
ex: Chemicals, high temperatures, UV light, radiation
 Body Cell Mutations-only effect person
 Sex Cell Mutations- Passed on to offspring.

3. How Do we protect the dna from mutations?
Cells have “proof reading” proteins that constantly check the DNA and fix errors, so most are corrected.
However, some slip through the cracks…

4. Recall: Triplet Code – codons Ribosome reads in codons,
or the triple code.

5. Examples:
Original DNA Code:
THE DOG BIT THE CAT

6. Substitution - Replace just one letter
THE DOG BIT THE CAT
THE DOG BIT THE CAR

7. Deletion: Delete just one letter (T from “bit”)
THE DOG BIT THE CAT
THE DOG BIT HEC AT

8. Insertion - Add just one letter (E in “dog”)
THE DOG BIT THE CAT
THE DOE GBI TTH ECA T

9. Frameshift Mutation: Changes the reading frame of the DNA
Frameshift Mutation: Changes the reading frame of the DNA. (shifts the codons)
Ex: Insertion, Deletion
Ex: Normal vs. Mutation
DNA: TAC GAT TAG DNA: TAA CGA TTA C
mRNA: AUG CUA AUC RNA: AUU GCU AAU C
Protein: Met-Leu-Ile Protein: Ile-Ala-Asn
Reading Frame = Triplet Code

10. Duplication Mutation- Part of the DNA is copied twice or more.
Ex: Normal vs. Mutation
DNA: TAC GAT TAG DNA: TAC GAT GAT TAG
mRNA: AUG CUA AUC RNA: AUG CUA CUA AUC Protein: Met-Leu-Ile Protein: Met-Leu-Leu-Ile

11. Point Mutation- Change in one nitrogenous base.
Sometimes this will not alter the amino acid sequence because of the duplicates in the codons that code for an amino acid.
Change No Change
DNA: AAA  ATA DNA: TAATAG
RNA: UUU  UAU RNA: AUU AUC
Protein: Phe  Tyr Protein: IleIle