C-Notes: Mutations

1. C-Notes: Mutations Stnd: BI.4.c 10/23/13 SWBAT describe how mutations in DNA may or may not affect the sequence of amino acids in proteins. Objective:

2. What codes for the protein to stop and start the process of protein synthesis? Start CodonsAUG Stop Codons UAA,UAG,UGA • It does NOT code for the tRNA to search for an amino acid, it is just a signal that the protein is done being made.

3. How are the codons (genetic code) Redundant and Unambigous? • Redundant • two or more codons differing only in their 3rd base can code for the same amino acids (UUU & UUC = phenylalanine) • Unambiguous • codons code for only ONE amino acid (UUU ONLY codes for phenylalanine)

4. What happens when a MISTAKE is made in DNA Replication or RNA Transcription ( 1st stage of protein synthesis)? • Mutations

5. What are Mutations? • mistakes made in replicating DNA in Replication, or transcribing (transcription) their own DNA to RNA for Protein Synthesis. • Changes the DNA • Changes the mRNA • May change protein • May change trait **changes in the genetic material** A loss of information in the cell leads to a loss of some function

6. What causes Mutation? • This is known as Mutagens • are things that can cause a change in DNA sequences. • All of these mutagens can damage your DNA: • UV light • radiation • exposure to chemicals

7. What are the Pros and Cons of Mutations? • PRO: mutations are the source of genetic variability (diversity)in a species! • CON: mutations can disrupt normal biological activity, resulting in a genetic disorder or cancer.

8. What are the TWO different types of Mutations? • Point Mutation (Substitution) (3 types) • One N-base is substituted for another changing the meaning of only one codon. • Missense Mutation • If a substitution changes the amino acid • Silent Mutation • If a substitution DOES NOT change the amino acid • Nonsense Mutation • If a substitution changes the amino acid to a “STOP” codon • Frameshift Mutation (2 types) • ALTER everything that follows! • Addition/Insertion • An extra N-base is added or inserted • Deletion • A N-Base is lost or deleted Deletion and Insertion my cause what’s called a FRAMESHIFT mutation, meaning the reading “frame” changes, thus changing the amino acid sequence from this point forward.  Big changes to proteins **Changes to the letters (A,C,T,G bases) in the DNA**

9. DNA Mutations • To illustrate DNA mutations, we’re going to use this sentence as an example: THEDOGBITTHECAT THE DOG BIT THE CAT • We’ll also use this DNA/RNA/aa sequence: TAC TTC AAA CCC CGT AAC ATT AUGAAGUUU GGG GCA UUG UAA Met – Lys – Phe – Gly – Ala – Leu -SXP

10. Point Mutations: missense mutation • Missense mutations result in a single amino acid change within a protein. • This DOES change the resulting protein. THE DOG BIT THE CAT THE DOG BIT THE CAR

11. change! Point Mutations: missense mutation TAC TTC AAA CCC CGT AAC ATT AUG AAG UUU GGG GCA UUG UAA Met - Lys - Phe -Gly- Ala - Leu-STP TAC TTC AAA TCC CGT AAC ATT AUG AAG UUU AGG GCA UUG UAA Met - Lys - Phe-Arg- Ala - Leu-STP

12. Point Mutations: nonsense mutation • Nonsense mutations create a premature stop codon, causing the protein to be shortened. • This DOES change the resulting protein. THE DOG BIT THE CAT THE DOG BIT

13. change! Point Mutations: nonsense mutation TAC TTC AAA CCC CGT AAC ATT AUG AAG UUU GGG GCA UUG UAA Met - Lys - Phe -Gly- Ala - Leu-STP TAC TTC AAA CCC CGT ATC ATT AUG AAG UUU GGG GCA UAG UAA Met - Lys - Phe - Gly- Ala - stop-STP

14. Point Mutations: silent mutation • Silent mutations change the DNA sequence, but not the amino acid sequence. • This DOES NOT change the resulting protein, and has no effect on an organism. THE DOG BIT THE CAT THE DOG BIT THE KAT

15. NO change! Point Mutations: silent mutation TAC TTC AAA CCC CGT AAC ATT AUG AAG UUU GGG GCA UUG UAA Met - Lys - Phe -Gly- Ala - Leu-STP TAC TTC AAA CCA CGT AAC ATT AUG AAG UUU GGU GCA UUG UAA Met - Lys - Phe - Gly- Ala - LeuSTP

16. Frameshift Mutations • Frameshift mutations result from the insertion or deletion of one or more bases into or from the DNA sequence. • This alters the grouping of nucleotides into three-base codons, causing a shift in the “reading frame” during translation. • The resulting protein is usually nonfunctional.

17. we’re going to insert another “D” we’re going to delete this “D” Frameshift Mutations THE DOG BIT THE CAT THE DDO GBI TTH ECA THE DOG BIT THE CAT THE OGB ITT HEC ATS

18. we’re going to delete this “A” Frameshift Mutations TAC TTC AAA CCG CGT AAC ATT AUG AAG UUU GGG GCA UUG UAA Met - Lys - Phe -Gly- Ala - Leu-STP TAC TTC AAC CGC GTA ACA TTT AUG AAG UUGGCG CAU UGU AAA Met - Lys - Leu- Ala - His - Cys- Lys

19. Example 1 – Sickle Cell Anemia • Sickle cell anemia is the result of a Missensepoint mutation.

20. Sickle cell anemia • Hemoglobin protein in red blood cells • strikes 1 out of 400 African Americans • limits activity, painful & may die young Normalround cells Misshapensickle cells Only 1 out of146 amino acids

21. Example 1 – Sickle Cell Anemia Sickle-cell anemia is a disorder that gets its name from the sickle shape of the red blood cells. The sickled red blood cells are caused by a mutation in the hemoglobin of the person with the disorder (one base is changed for another Missense Mutation) Hemoglobin is the main protein in red blood cells. Each hemoglobin molecule carries oxygen from the lungs to all other parts of the body.

22. What is Chromosomal Mutations? • changes in the number or structure of chromosomes • occur when chromosomes fail to properly separate during meiosis. **typically harmful in humans*

23. What are the types of Chromosomal Mutations? • Deletion • Loss of part of the chromosome • Duplication • Extra copies of part of the chromosome are made • Inversion Reverse the direction of some of the chromosome • Translocation • Part of the chromosome breaks off and attaches to another chromosome/

24. ChromosomalMutations: DELETION

25. ChromosomalMutations: DELETION DUPLICATION

26. ChromosomalMutations: DELETION DUPLICATION INVERSION

27. ChromosomalMutations: DELETION DUPLICATION INVERSION TRANSLOCATION