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. **changes in the genetic material**
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. UV light radiation exposure to chemicals 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
AUG AAG UUU 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. 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
change!

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. 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
change!

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. 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 - Leu STP
NO change!

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

18. AUG AAG UUG GCG CAU UGU AAA
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 UUG GCG CAU UGU AAA
Met - Lys - Leu - Ala - His - Cys - Lys
we’re going to delete this “A”

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

20. Sickle cell anemia Hemoglobin protein in red blood cells
strikes 1 out of 400 African Americans
limits activity, painful & may die young
Normal round cells
Misshapen sickle cells
Only 1 out of 146 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. Chromosomal Mutations:
DELETION

25. Chromosomal Mutations:
DELETION
DUPLICATION

26. Chromosomal Mutations:
DELETION
DUPLICATION
INVERSION

27. Chromosomal Mutations:
DELETION
DUPLICATION
INVERSION
TRANSLOCATION