* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Sickle cell / mutations
Metagenomics wikipedia , lookup
Genome evolution wikipedia , lookup
Genomic library wikipedia , lookup
Gel electrophoresis of nucleic acids wikipedia , lookup
United Kingdom National DNA Database wikipedia , lookup
Designer baby wikipedia , lookup
Human genome wikipedia , lookup
DNA vaccination wikipedia , lookup
Saethre–Chotzen syndrome wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Population genetics wikipedia , lookup
Molecular cloning wikipedia , lookup
Bisulfite sequencing wikipedia , lookup
Koinophilia wikipedia , lookup
Epigenomics wikipedia , lookup
Zinc finger nuclease wikipedia , lookup
Primary transcript wikipedia , lookup
Cancer epigenetics wikipedia , lookup
SNP genotyping wikipedia , lookup
Genealogical DNA test wikipedia , lookup
Extrachromosomal DNA wikipedia , lookup
Expanded genetic code wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
DNA supercoil wikipedia , lookup
Cre-Lox recombination wikipedia , lookup
Nucleic acid double helix wikipedia , lookup
DNA damage theory of aging wikipedia , lookup
History of genetic engineering wikipedia , lookup
Non-coding DNA wikipedia , lookup
Oncogenomics wikipedia , lookup
No-SCAR (Scarless Cas9 Assisted Recombineering) Genome Editing wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Cell-free fetal DNA wikipedia , lookup
Nucleic acid analogue wikipedia , lookup
Genome editing wikipedia , lookup
Deoxyribozyme wikipedia , lookup
Genetic code wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Helitron (biology) wikipedia , lookup
Microsatellite wikipedia , lookup
Microevolution wikipedia , lookup
Name _______________________________________________ Date _____________ Biology 9 Genetic Mutations Part I: Preview Questions 1. Based on your current knowledge, how would you define a mutation? What does this word make you think of? (2 pts) 2. Unlike popular misconceptions about people with green skin or extra body parts, a mutation is simply a change in the nucleotide sequence, or base pair sequence, of DNA. Most mutations are either neutral (they have no effect) or harmful, but occasionally mutations can actually cause a helpful change. Some mutations change only a single base in the DNA sequence – these are called point mutations. Other mutations can be larger-scale changes in a chromosome, such as cutting out, copying, or switching around a long chunk of DNA. Based on the paragraph above, write a one-sentence definition for a mutation. Then explain how this is similar or different to what you thought a mutation was (see your answer to #1). (2 pts) 3. This packet focuses on point mutations – changing a single nucleotide in a DNA sequence. There are three ways to create a point mutation: substitution (switch one DNA nucleotide for another) insertion (add an extra nucleotide into the DNA sequence) deletion (leave out one nucleotide in the DNA sequence) Make a prediction: which of these changes do you think will have the biggest effect the amino acid sequence encoded by the DNA? Which will have the smallest effect? Why? (3 pts) 1 Part II: Types of Mutations Below is the original DNA sequence we will work with. Your first task is to transcribe and translate it into an amino acid sequence for a protein (2 pts) Original Gene Sequence DNA TAC mRNA A.A.s TTA TAG TTA AAC CCA CAA ACT Substitution Mutations In a substitution mutation, one nucleotide is switched for another. We will look at two examples. In example #1, the third base of the 5th codon has been switched from C to A. Transcribe and translate the gene again to see how this affects the protein. (2 pts) Example #1: Substitution Mutation DNA TAC TTA TAG mRNA A.A.s TTA used to be C in the original gene AAA CCA CAA ACT Compare the new amino acid sequence with the original. How and why is it different? (2 pt) Now we’ll look at another example of a substitution mutation. We’ll change the same nucleotide, but this time we’ll change it from C to T. This example is in a category called “silent mutations.” Transcribe and translate the gene to figure out why: (2 pts) Example #2: Silent Mutation DNA TAC TTA TAG mRNA A.A.s TTA used to be C in the original gene AAT CCA CAA ACT Compare this amino acid sequence with the original (not with example #1). Why do you think this is called a “silent” mutation? (2 pts) 2 Frame-Shift Mutations Another category of mutations is called frame-shift mutations. This includes inserting or deleting a nucleotide from the DNA sequence. In the example below, we will delete the first nucleotide in the 4th codon. Transcribe and translate to see what happens: (2 pts) Example #3: Deletion Mutation DNA TAC TTA TAG mRNA A.A.s T was deleted from here TAA ACC CAC AAA CT Compare this amino acid sequence with the original. How and why is it different? (2 pts) For the final example, we will insert an extra nucleotide into the 4th codon. Transcribe and translate: (2 pts) Example #4: Insertion Mutation DNA TAC TTA TAG mRNA A.A.s this A was added in ATT AAA CCC ACA AACT Compare this amino acid sequence with the original. How and why is it different? (2 pts) Analysis Questions for Part II: 1. Think about the phrase “frame shift.” Why do you think adding or deleting a nucleotide is called a “frame shift” mutation? (1 pt) 2. Which type of mutation tends to have a bigger effect on the amino acid sequence of a protein – a substitution, or a frame shift mutation? Why? (2 pts) 3. Describe the type of mutation that you think would be most likely to be harmful to an organism. Then describe the type of mutation that would be least likely to be harmful. Explain your reasoning. (3 pts) 3