2 point mutations chemical changes in just one base

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2. Point Mutations - Chemical changes in just one base pair of a gene. A C T G C A T Gets damaged and gets replaced with an A l –l –l –l –l –l –l T G A C G T A Gets damaged and gets replaced with a T ACT UGA (stop codon) 3. Types of Point Mutations A. Substitutions - A base-pair substitution in which a base and it complementary partner of removed and replaced with a new base-pair. * sickle cell Anemia - this can result in the insertion of a different AA into the protein and perhaps changing the function of that protein (Fig. 8.8, p. 204) - missense mutation - still form a protein that may or may not be functional
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- What is a neutral mutation? Even though it is a mutation it doesn't really change. - nonsense mutation - alteration might code for a stop codon prematurely ending the formation of a protein - almost always lead to nonfunctional protein B. Insertions and Deletions - additions or losses of base-pairs - alters the reading frame (When a letter in DNA is added and it messes up the pervious groups of three: AACGGT ATACGGT) - frameshift mutation - occurs if base-pairs are inserted or deleted in multiples of something other than 3 - Fig. 8.9, p. 205 - How do deletions work? Example: THE DOG SAW THE CAT What happens if we delete the first E (remember a codon consist of three bases (THE, DOG, SAW, THE, CAT) THD OGS AWT HEC AT? What would happen if we inserted an A after the first H? THA EDO GSA WTH ECA T???
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