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Published byWinfred White Modified over 7 years ago
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Wednesday, January 16 th What is a mutation? Reminders: DNA Test Friday
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What is the difference between the following mRNA strands? AUG CCG AUU UAG AUG CGA UUU AG
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Mutations
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What Are Mutations? Changes in the nucleotide sequence of DNA May occur in body cells (aren’t passed to offspring) May occur in gametes (eggs & sperm) and be passed to offspring
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Are Mutations Helpful or Harmful? Mutations happen regularly Almost all mutations are neutral Chemicals & UV radiation cause mutations Many mutations are repaired by enzymes
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Are Mutations Helpful or Harmful? Some type of skin cancers and leukemia result from body cell mutations Some mutations may improve an organism’s survival (beneficial)
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Types of Mutations Chromosome Gene
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Gene Mutations Change in the nucleotide sequence of a gene May only involve a single nucleotide May be due to copying errors, chemicals, viruses, etc.
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Types of Gene Mutations Include: –Point Mutations –Frameshift Insertion Deletion –Substitutions –Inversion –Translocation
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Point Mutation Change of a single nucleotide Includes the deletion, insertion, or substitution of ONE nucleotide in a gene
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Point Mutation Sickle Cell disease is the result of one nucleotide substitution Occurs in the hemoglobin gene
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Frameshift Mutation Inserting or deleting one or more nucleotides Changes the “reading frame” like changing a sentence Proteins built incorrectly
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Frameshift Mutation Original: –The fat cat ate the wee rat. Frame Shift (“a” added): – The fat caa tet hew eer at.
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Amino Acid Sequence Changed
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Substitution Mutation A nitrogen base is replaced (substituted) with another nitrogen base.
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Inversion Mutation An entire section of DNA is reversed!
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Gene Mutation Animation
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Translocation Mutation A segment of DNA moves from one part of the sequence to another part CCA TGC ATA CGG ATA CCA TGC CGG Original
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DNA Mutation Practice
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AUG UGG AAC CGC UGC UGA Met Trp Asn Arg Cys Stop
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