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Mutation: Any change or error in DNA

Mutation: Any change or error in DNA. If mutations occur in reproductive cells, the altered gene will become part of the genetic makeup of the offspring. If mutations occur in somatic cells (body cells), the mutation will not be passed on. However, problems may arise for the individual.

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Mutation: Any change or error in DNA

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  1. Mutation:Any change or error in DNA

  2. If mutations occur in reproductive cells, the altered gene will become part of the genetic makeup of the offspring. • If mutations occur in somatic cells (body cells), the mutation will not be passed on. • However, problems may arise for the individual.

  3. Mutagen: any agent that causes a change in DNA • Radiation such as ultraviolet light, X rays, or radioactivity • Chemicals including asbestos, cyanide, formaldehyde, tobacco

  4. mutated base I. Point Mutation • A change in a single base pair in DNA

  5. Substitution mutation GGTCACCTCACGCCA ↓ CCAGUGGAGUGCGGU ↓ Pro-Arg-Glu-Cys-Gly A. Substitution: one base is changed to another Normal gene GGTCTCCTCACGCCA ↓ CCAGAGGAGUGCGGU Codons ↓ Pro-Glu-Glu-Cys-Gly Amino acids Substitutions will only affect a single codon Their effects may not be serious unless they affect an amino acid that is essential for the structure and function of the finished protein molecule (e.g. sickle cell anemia)

  6. Substitution mutation causing sickle cell anemia

  7. B. Inversion: two bases switch position Inversion mutations, also, only affect a small part of the gene Inversion mutation GGTCCTCTCACGCCA ↓ CCAGGAGAGUGCGGU ↓ Pro-Gly-Glu-Cys-Gly Normal gene GGTCTCCTCACGCCA ↓ CCAGAGGAGUGCGGU Codons ↓ Pro-Glu-Glu-Cys-Gly Amino acids

  8. C. Deletion: one base is deleted A frame shift mutation, because it shifts the reading of codons by one base Normal gene GGTCTCCTCACGCCA ↓ CCAGAGGAGUGCGGU Codons ↓ Pro-Glu-Glu-Cys-Gly Amino acids Deletion mutation GGTC/CCTCACGCCA ↓ CCAGGGAGUGCGGU ↓ Pro-Gly-Ser-Ala-

  9. D. Insertion: one base is added A frame shift mutation, because it shifts the reading of codons by one base Normal gene GGTCTCCTCACGCCA ↓ CCAGAGGAGUGCGGU Codons ↓ Pro-Glu-Glu-Cys-Gly Amino acids Insertion mutation GGTCTGCCTCACGCCA ↓ CCAGACGGAGUGCGGU ↓ Pro-Asp-Gly-Val-Arg

  10. Question: Which type of mutation would have a greater effect on the sequence of amino acids in a protein, a substitution mutation or a deletion mutation? Explain

  11. II. Chromosomal Mutations • Occur during mitosis or meiosis; parts of chromosomes break off and are lost or rejoin incorrectly. • Pictures p. 321

  12. Deletion: Part of a chromosome is left out • Insertion: part of a chromatid breaks off and attaches to its sister chromatid. (this can also be called a duplication)

  13. C. Inversion: part of a chromosome breaks off and is reinserted backwards D. Translocation: part of one chromosome breaks off and is added to a different chromosome

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