1. Do Now The function of the BRCA1 protein is to prevent our cells from becoming cancerous. If a cell is dividing too much, the BRCA1 protein can repair the cell so that it undergoes mitosis normally. A portion of the BRCA1 gene (the DNA with instructions on how to make the BRCA1 protein) is shown below. TAC TGA GTT ACA CGA Write out the sequence of mRNA that would be produced during transcription of the BRCA1 gene.

2. Use the genetic code chart to determine the amino acids that make up this portion of the BRCA1 protein. What would happen if a person’s BRCA1 protein was not functional?

3. What is this diagram saying? Nucleotide Sequence Amino Acid Sequence Protein Shape Protein Function

4. What is this diagram saying? Nucleotide Sequence Amino Acid Sequence Protein Shape Protein Function HISLEUVALGLY

5. Protein SHAPE determines FUNCTION.

6. FACT: FACT: Many people with breast cancer have BRCA1 proteins that are the wrong shape or missing amino acids. How does this happen? Mutations!

7. Mutation Type DescriptionExample DNA Sequence Substitution One base is switched with another Original : ATCTGG Mutated : TTCTGG InsertionA base is added to a sequence Original :ATCTGG Mutated: ATCTGGG DeletionA base is removed from a sequence. Original : ATCTGG Mutated : ATCTG 3 Types of Mutations

8. Identify the Mutation Mutation A: ___________________________ Mutation B: ____________________________ Mutation C: ____________________________ GTTACGAA GTTACTGAA GTACGAA GTTATGAA

9. mutation Based on what you have learned thus far, create your own definition of what a “mutation” is Stop and Jot

10. Mutation Mutation- a random change in the sequence of bases. Word of the Day

11. Discussion Question Insertions and deletions are often called “frameshift mutations” and are far more dangerous than substitution mutations. Why would an insertion or deletion be worse than a substitution?

12. Cancer Connection Compare the beginning sequence of Theresa ’ s BRCA1 gene to the normal sequence below. Theresa ’ s BRCA1 gene: TACTGAGTTACTACGA Normal BRCA1 gene: TACTGAGTTACACGA

13. Cancer Connection mRNA codons How would her mRNA codons be different than a normal person’s? amino acid sequence How would her amino acid sequence be different than a normal person’s?

14. Cancer Connection protein function State how the BRCA1 protein function would be altered as a result of this mutation.

15. Cancer Connection Synthesize all of the information that you learned today to describe why so many people in Theresa’s family have breast cancer.

16. Cancer Connection Sample data from a patient is shown below. Fill in the patient’s missing codon. DNA Sequence mRNA Sequence A. Acid Sequence Protein Shape NormalTAC TGA GTT ACA CGA AUG ACU CAA UGU GCU Met Thr Gln Cys Ala Normal BRCA1 PatientTAC TGT GTT ACA CGA AUG ____ CAA UGU GCU Met Thr Gln Cys Ala Normal BRCA1

17. Cancer Connection The patient’s BRCA1 protein is normal despite the fact that the BRCA1 gene has a mutation. Explain how this is possible in terms of the genetic code.