1. Aim: How is protein shape determined?

2. All are proteins with a specific shape that determines their function.
What do enzymes, antibodies, hormones, hemoglobin and membrane proteins have in common?
All are proteins with a specific shape that determines their function.
Enzymes
Hormone
Hemoglobin
Antibodies

3. What determines a protein’s Shape?
A protein’s shape is determined by its sequence of amino acids.

4. Protein Shape: The DNA base sequence (order) determines
the sequence of amino acids.
2) The sequence (order) of amino acids in a
protein determine its shape.
3) The shape of a protein determines its activity/function.

5. Transcription & Translation:
Therefore it is the genetic code/ DNA base sequence that ultimately determine a protein’s sequence of amino acids.
A – T U
C – G G Tryptophan
C – G G

6. Mutations
Mutations can lead to changes in the amino acid sequence and ultimately to the overall shape of the protein. Why?

7. Why?
If the DNA sequence changes then the amino acid sequence changes then the protein shape changes then the protein will not be able to perform its job or function.

8. What causes mutations errors in DNA replication?
Chemicals
UV Radiation
X-Ray radiation

9. It changes the amino acids sequence which determines protein shape
Mutated Proteins
It changes the amino acids sequence which determines protein shape

10. How does a mutated protein affect a cell?
The mutated protein may have a different shape and disrupt its normal activity.

11. Types of Mutation Substitution Deletion Insertion Inversion
Original DNA Strand

12. Copy the Normal DNA Strand:
DNA CCT CAA GAT GCG
GGA GUU CUA CGC
RNA
AA Sequence
Gly – Val – Leu - Arg

13. Substitution and Deletion Mutations
Substitution – One nitrogenous base is substituted for another.
DNA CCC CAA GAT GCG
mRNA GGG GUU CUA CGC
Deletion – One nitrogenous base is deleted (removed).
DNA CTC AAG ATG CG
mRNA GAG UUC UAC GC

14. Insertion and Inversion Mutations
Insertion – Extra nitrogenous bases are added to the genetic code.
DNA CCT CTA AGA TGC G
mRNA GGA GAU UCU ACG C
Inversion – The genetic code is inverted or reversed.
DNA CCT CAA TAG GCG
mRNA GGA GUU AUC CGC

15. Sickle Cell Anemia

16. Point and Frame Shift Mutations
Point mutation
A change in ONE nitrogenous base, the overall number of bases stays the same (Substitution or Inversion)
Frame shift mutation
A change in the number of overall nitrogenous bases in the genetic code (Addition or Deletion)

17. What type of mutation is it?

18. Use the chart to complete your hand out