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andreathors16
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mutation
- a change in the DNA sequence that results in a change in the product protion
- can be neutral harmful or benificial
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base substitution
single base in the DNA sequence is replaced with a different base
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missence mutation
- base substitution results in amino acid substituion in protien
- may or may not affect activity of protien
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nonsense mutation
- creates a stop codon in the middle of an mRNA molecute
- almost always destroys activity of protien
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frameshift mutation
- nucleotide pairs are deleted or inserted into the DNA
- protien sequence altered significantly
- produce carcinagens
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mutagens
agents in the enviornment such as chemicals and radiation that directly or indirectly bring about mutations
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chemical mutagen
ex nitrous acid makes base pair change in DNA and alters DNA at random location
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nucleoside analog
- altered base pairs
- randomly incorporated into DNA instead of normal base
- replication causes base pair substitutions in later generations
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radiation
- xray /gamma ray ionize atoms and molecules
- ions combine with bases in dna - errors in replication
- causes physical breaks in the chromosome
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uv light
- nonionizing cases formation of covalent bonds between bases
- creates thymine dimers - may cause death to cell
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photolyases
light repair enzymes use visible light to seperate dimer to two thimines
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repair uv light
- enzyme cut and remove damaged DNA
- DNA polymerase synthesizes Dna to fill gap
- DNA ligase seals gap by joining old and new DNA
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frequency of mutation
- rate at which mutation will occur
- 1/million rate. - provides genetic diversity
- rate can change depending on population cell has been exposed to.
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Restriction enzyme
- DNA cutting enzymes that exsist in many bacteria
- recognize and cuts particular sequence of nucleotide bases in DNA 4,6,8 base sites
- palindrome
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Linn and Abner
- discovered some strains of bacteria were able to resist bacteriaphage
- infection by infecting DNA
- different bacteria produce different enzymes
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blunt ends
cut both strands of DNA in the same place
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sticky ends
cut two strands that are not directly opposite from each other (stagger ends)
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restriction enzyme steps
- enzyme cutes DNA making skicky ends
- DNA from another pasmid joins to sticky ends through base pairing
- DNA ligase fuses them together making a molecule of recombinant DNA
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plasmids
- carry on antibiotic resistance markers
- restriction sites to insert DNA
- allow plasmids to reproduce in several organisms
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polymerase chain reaction
- small samples of DNA can be doubled
- heat/cold
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polymerase chain reaction steps
- separate targe DNA with heat
- need primer deoxynucleotides and DNA polymerase
- polymerase synthesizes strands two new forms of target DNA are formed
- repeate and DNA strands are doubled
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primer
- help start the reaction
- complementary to ends of target DNA
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agarose gel electrophoresis
- separate DNA fragments made with restriction enzymes
- used to sequence DNA
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Cohen and Boyer
- cut plasmid DNA and target dna with same restriction enzyme
- mix DNA allowing sticky ends to match up
- select DNA clone having target gene
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