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Gene Regulation and Mutations. Can the letters of any word be rearranged to form another word in English? Give examples. If you rearranged the letters at random, is it likely that you would form another English word? Explain your answer.
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Can the letters of any word be rearranged to form another word in English? Give examples. • If you rearranged the letters at random, is it likely that you would form another English word? Explain your answer. • If the protein “building blocks” that create cells were rearranged at random, do you think that a useful change in the cell would result? Explain your answer.
A. Gene Regulation 1. DNAcontains a lot of instructions to makemanydifferentproteins. a. Not everyproteinisneeded at all times.
2. GENE REGULATIONis an organism’sability to control whichgenes are transcribedwhen, in response to need/environment.
Thinking question: DoesGENEREGULATIONoccur in bothPROKARYOTES and EUKARYOTES? Thinking question: Do youthink the processisdifferent?
a. GENE REGULATIONoccursdifferently in PROKARYOTES and EUKARYOTES. An exampleincludesphysical changes observedduringa growthspurtin humans.
B. Mutations 1. Occasionally, an erroroccursduringDNA REPLICATION. a. Most errors are repaired by the cell. THINKING QUESTION: Which enzyme repairserrorsduringDNA REPLICATION?
2. A permanent change in a cell’sDNAsequenceiscalled a MUTATION. a. MUTATIONScan range fromchanging a single base pair to the addition or removal of entiresections of DNA.
b. MUTATIONScan cause differenteffects in an organism, from no impact to illness to death.
C. Mutation Types 1. POINT MUTATIONS are changes in a single base pair. a. A SUBSTITUTIONis a POINT MUTATIONwhere one base replaces another.
2. SUBSTITUTIONS can impact AMINO ACIDS (A.A.)in threeways: a. MISSENSE – the original A.A. ischanged to another (ACU Thr AAU Asn).
b. SILENT – the A.A. is not changed (ACU Thr ACC Thr). c. NONSENSE – the A.A. ischanged to a STOP CODON (UGC Cys UGA Stop).
3. FRAME SHIFT MUTATIONSdisrupt the groups of three bases by adding or removing a NUCLEOTIDE. a. INSERTIONSadd one. b. DELETIONS remove one.
4. OtherMUTATIONSinvolve changes of larger portions of DNA. a. Ex: An entire extra copy of CHROMOSOME 21 results in Down Syndrome.
Let’s Practice Mutations This is the original DNA sequence: ATG CGA CGT GAA TTC GAT CAG ATG CGA CGT GAT ATT CGA TCA G What type of mutation is this? INSERTION!
Let’s Practice Mutations This is the original DNA sequence: ATG CGA CGT GAA TTC GAT CAG ATG CGA CGT GAA TTC GCT CAG What type of mutation is this? SUBSTITUTION!
Let’s Practice Mutations This is the original DNA sequence: ATG CGA CGT GAA TTC GAT CAG ATG TGC AGC GAA TTC GAT CAG What type of mutation is this? INVERSION!
This is the original DNA sequence: ATG CGA CGT GAA TTC GAT CAG ATG CGA CGT GAA TCGATC AG What type of mutation is this? DELETION!
D. Mutation Causes 1. RandomMUTATIONS duringDNA REPLICATION are rare, and usuallyrepaired by DNA POLYMERASE. a. Most are caused byMUTAGENS– substances in the organism’senvironmentthat change DNAsequences.
2. MUTAGENSincludethingslikechemicals, radiation, and cigarette smoke.
3. MUTATIONS in body cellsmay affect the organism,but may not pass on to offspring. Sperm/eggcellMUTATIONS are passed on. a. NOT all MUTATIONS are harmful. Theycreatediversity andcan help organismssurvive.
POINT MUTATIONS Substitution- one base replaces another Describes the change in DNA Describes change in AA MISSENSE mutation changes the amino acid. SILENT mutation does not change amino acid. NONSENSE mutation changes A.A. to stop codon.
FRAME SHIFT MUTATIONS These typically affect EVERY amino acid after the place where the mutation occurred. INSERTIONS add an extrabase. DELETIONS remove a base.
