1.  BUILD-A-BUG ACTIVITY  Build your bug and turn in to your box  Mutations Notes  Mutations practice QUIZ NEXT CLASS: Transcription and Translation TUESDAY IN BIOLOGY

2.  Transcription: transcribing DNA into mRNA  Example  DNA: TACAAATTAGCG  mRNA: AUG-UUU-AAU-CGC  Translation: translating the message in RNA into an amino acid sequence (use your codon chart)  Example  mRNA: AUG-UUU-AAU-CGC  AA: Meth-Phen-Asp-Arg  Gene expression: What traits does your bug have? Build a bug to express the genes!! REMINDERS THAT YOU NEED TO KNOW!!! DNA  RNA A U T A G C C G

3. MUTATIONS

4. Mutation – a random change in the sequence of a gene Caused by: – Mistakes in DNA replication process – Environmental agents that damage DNA What are DNA Mutations? ATCGA TAGCT ATCGA TAGCT ATCAA TAGCT

5. Point mutation/Substitution Inversion Insertion Deletion Translocation Types of DNA Mutations C T C G A T A

6. Point mutation/Substitution – one base replaced with another base Inversion – order of two or more bases is reversed Types of DNA Mutations

7. Insertion – addition of one or more new bases Deletion – removal of one or more bases Types of DNA Mutations

8. Translocation – movement of one or more bases to a new location in a different DNA sequence Types of DNA Mutations

9. Changes in sequence of a gene can cause changes to the protein that is produced during translation Can affect proteins produced in different ways: – Silent mutations – Missense mutations – Nonsense mutations – Frameshift mutations DNA Mutations

10. Silent mutation – mutation that causes no change in amino acid sequence Genetic code has redundancies Caused by point mutations Silent Mutations …TACAACCTCACC… …ATGTTGGAGTGG… …AUGUUGGAGUGG… Met-Leu-Glu-Trp… DNA (transcription) RNA (translation) Protein …TACAATCTCACC… …ATGTTAGAGTGG… …AUGUUAGAGUGG… Met-Leu-Glu-Trp…

11. Missense mutation – mutation that changes the identity of an amino acid added Most often because of point mutations May be because of inversions Missense Mutations …TACAACCTAACC… …ATGTTGGATTGG… …AUGUUGGAUUGG… Met-Leu-Asp-Trp… DNA (transcription) RNA (translation) Protein …TACAACCTCACC… …ATGTTGGAGTGG… …AUGUUGGAGUGG… Met-Leu-Glu-Trp…

12. Nonsense mutations – mutation that shortens a protein by replacing an amino acid codon with a stop codon Most often because of point mutations Large impact on protein produced Nonsense Mutations …TACAACATGACC… …ATGTTGTACTGG… …AUGUUGUACUGG… Met-Phen-Tyr-Trp… DNA (transcription) RNA (translation) Protein …TACAACATCACC… …ATGTTGTAGTGG… …AUGUUGUAGUGG… Met-Phen-STOP

13. Frameshift mutation – mutation that alters the reading frame in which codons are translated Caused by insertions, deletions, and translocations Large impact on protein produced Frameshift Mutations …TACAACATGACCCTA… …ATGTTGTACTGGGAT… …AUGUUGUAUUGGGAU … Met-Leu-Tyr-Trp-Asp… DNA (transcription) RNA (translation) Protein …TACAACTATGACCCTA… …ATGTTGATACTGGGAT… …AUGUUGAUAUUGGGAU … Met-Leu-Ile-Leu-Gly…

14. Mutations can be organized by their effect Neutral mutations – no effect on organism’s survival – Increase genetic diversity in a species – Example: human eye color Harmful mutations – decrease organism’s survival – Produce genetic disorders or unfavorable traits – Example: cancers Beneficial mutations – increase organism’s survival – Produce favorable traits – Example: antibiotic resistance in bacteria DNA Mutations and Survival