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When things go wrong in the DNA!
Mutations! When things go wrong in the DNA!
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Objective (YOUR GOAL BY THE END OF THE CLASS PERIOD
Objective (YOUR GOAL BY THE END OF THE CLASS PERIOD!): I will be able to identify mutations in a DNA sequence
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Mutated Frog
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What is a Mutation? Mutations = a permanent change in the DNA sequence
- A base (letter) in the DNA is changed
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What is the effect of a mutation?
Mutations are a natural process that can lead to: No effect nothing happens to the phenotype Beneficial effect phenotype is affected. The organism is better adapted to its environment Harmful effect phenotype is different. The organism is less adapted to it environment
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How do mutations affect proteins?
Proteins have to be folded a certain way to work Mutations can change the type of amino acids in the polypeptide This can change how the protein folds = may no longer work
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What causes mutations? Mutagens: Environmental factors such as UV light, x-rays, cigarette smoke, etc. As DNA replicates, sometimes mistakes can occur
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Mutations in DNA may cause cancer
Cancer: uncontrolled cell growth Mutations may change the proteins that help control how fast cells divide Result: cells divide too quickly leading to cancerous tumors
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Cancerous Benign
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CFU Mutations within a DNA sequence are:
A Natural process that always affect the phenotype B Natural process that produce genetic diversity C Unnatural processes that always affect the phenotype D Unnatural processes that are harmful to genetic diversity
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Two types of gene mutations
1. Point (base substitution) mutations 2. Frameshift mutations
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1. Point Mutation Substitution of a nucleotide normal mutation
- One base is switched for a different base 1. Point Mutation normal mutation
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Point Mutations can either have an effect or have no effect
Ex: C – A – T – G – A – G C – A – G – G – A – G Ex) UAU= tyrosine UGU= cytosine Ex) Sickle Cell Anemia
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Sickle Cell Anemia Shape of the protein hemoglobin in your blood
GAA makes glutamic acid In sickle cell anemia, GAA is changed to GUA which makes valine
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Cystic Fibrosis
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2. Frameshift Mutation Example: ATCGTC ATTCGTC
Two types: Insertion: an extra nucleotide (base) is added to the sequence Example: ATCGTC ATTCGTC Deletion: A nucleotide (base) is missing Example: ATCGTC ACGTC Deletion of U
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What is the result of a frameshift mutation?
Causes the codons to shift and changes all the amino acids following the mutation Insertion Example Ex) The big fat cat The big sfa tca t Ex) C – A – T – G – A – G C – A – C – T – G – A – G Deletion Example Ex) The big fat cat Thb igf atc at Ex) C – A – T – G – A – G C – A – T – A – G
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Review: Difference between a point mutation and a frameshift mutation.
Which one do you think has a greater effect on the protein? Why?
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Checking for Understanding:
Original: THE DOG BIT THE CAT Mutation: THE DOG BIT THE CAR 1. Point or frameshift?
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Check for Understanding:
Original: THE DOG BIT THE CAT Mutation: THE DOB ITT HEC AT 2. Point or frameshift? Insertion or deletion?
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What types of mutations?
Frameshift: Insertion 3. 4. Frameshift: Deletion
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Catalyst 1. Identify the type of DNA mutation shown below: AGCTTGCCA AGCTTTGCCA A Insertion B Deletion C Substitution D Inversion 2. Which of the following would be most likely to cause a mutation: A When endoplasmic reticulum is missing ribosomes B When mRNA does not leave the nucleus the right way C All of the nitrogen bases are in the right order D A deletion of a nucleotide in DNA 3. What is the new door policy for my room?
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Announcements Homework packet due Friday
Tutoring today after school today and Thursday Extra credit for bringing in printer paper Peer health
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WEDNESDAY: Textbook Questions
Directions: Use Chapter 8.7 (pages ) to answer the following questions. THURSDAY: Multiple-Choice Questions Directions: Write five multiple-choice questions that could be used on the quiz. Make them creative and challenging. Each question should have four choices (a-d). Question #1: ______________________________________________________________________ a) _______________________________________________________________ b) _______________________________________________________________ c) _______________________________________________________________ d) _______________________________________________________________
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DO NOW Please place your Tuesday HW of your desk
Answer the following questions on the BACK of the Spiderman worksheet What is a mutation? Are mutations natural or unnatural? What are the different kinds of mutations we learned about yesterday? On your own, or with a partner, begin completeing the front of the Spiderman Mutation worksheet!
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Hint: Numbers 1-3 all occur near
the second A. Numbers 4-6 all occur near the last G. TAC GAT GGC TAC GTG GC 4. TAC GAT GAC deletion Substitution/ point mutation 2. TAC GGT GGC 5. TAC GAT GGT C substitution Insertion 3. TAG GAC TGG C 6. TAC GAT GC insertion
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For Questions 7-9: the original DNA sequence is ATT ACC GAG
For Questions 7-9: the original DNA sequence is ATT ACC GAG. You will create the examples of mutations that may occur in the DNA of a human skin cell. Indicate the location of the mutation by underlining. 7. Give an example of a point mutation given the above sequence ATT ACC GAC 8. Give an example of an insertion that may occur. ATT TAC CGA G 9. Give an example of a deletion that may occur. ATA CCG AG
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What are the two types of mutations
What are the two types of mutations? Which one do you think is more severe? Frameshift (insertion and deletion) and point mutation Frameshift is more harmful. How does a mutation result in the change in the protein created? The amino acids are the changed resulting in the protein to be different. Do you think most mutations are good or bad? Why? What causes mutations? What are some examples of mutagens? Mutagens: UV light, cigarette smoke, DNA replication mistakes, problem with the chromosomes, genetics
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DNA mutation video Discovery Channel – Human Mutations
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2. G – A – C – G – C – C – A – T – G – G – A – A – G – T – C
1. The following is a strand of DNA that a protein will be made from. Write the “transcripted” mRNA in the spaces below it. 2. G – A – C – G – C – C – A – T – G – G – A – A – G – T – C 3. __ - __ - __ - __ - __ - __ - __ - __ - __ - __ - __ - __ - __ - __ - __ 4. Draw a line between each codon. 5. Look up the amino acid for each codon on the codon chart and write them in the spaces below. Be sure to do this in order. This is the “normal protein.” 6. ________ - ________ - _______ - ________ - ________
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MUTATION ACTIVITY
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Word Wall mutation tRNA codon Point mutation anticodon gene
Frame shift mutation amino acid Insertion protein Deletion ribosome Mutagen transcription Polypeptide central dogma Translation RNA
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Genetic Disorders A genetic disorder is a disease that is caused by an abnormality in an individual's DNA. Abnormalities can range from a small mutation in a single gene to the addition or subtraction of an entire chromosome or set of chromosomes.
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