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VII) Mutations

VII) Mutations. Mutations. Any alteration in a gene from its natural state. the change may be detrimental or benign or lead to variation Point mutations a mutation at a specific base pair Gene mutation a mutation that changes the coding for amino acid. V) Mutations. Point Mutations.

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VII) Mutations

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  1. VII) Mutations

  2. Mutations • Any alteration in a gene from its natural state. • the change may be detrimental or benign or lead to variation • Point mutations • a mutation at a specific base pair • Gene mutation • a mutation that changes the coding for amino acid. V) Mutations

  3. Point Mutations • silent mutation • a mutation that does not result in a change in the amino acid code. (because there is redundancy in the genetic code for proteins some mutation will have no effect. CUG → Leucine CUA → Leucine • missense mutation • a mutation that results in the single substitution of amino acid in the polypeptide. CUG → Leucine GUG→ Valine V) Mutations

  4. Point Mutations • nonsense mutation • a mutation that converts a codon for an amino acid into a stop codon. UGC → cysteine UGA → stop V) Mutations

  5. Gene Mutations • deletion • the elimination of a base pair or a group of base pairs from a DNA sequence. GUU CUA UCU UAG UUC Val – Leu – Ser – Stop GUU CUA UCU UUU C Val – Leu – Ser – Phe • insertion • the placement of extra nucleotides in a DNA sequence GUU CUA UCU UAG UUC Val – Leu – Ser – Stop GUU CUA UCU UAC GUU C Val – Leu – Ser – Tyr - Val V) Mutations

  6. Gene Mutations • frameshift mutuation • a mutation that causes the reading frame of codons to change. UUU CUU CAU GAU AAG GGU CCA Phe – Leu – His –Asp –Lys – Gly – Pro UUU CUU CAU GAU AAG GGU CCA Phe – Phe - Met - Ile – Arg - Val V) Mutations

  7. Gene Mutations on a larger scale • translocation • the transfer of a fragment of DNA from one site in the genome to another location, usually between nonhomologous chromosomes • some types of leukemia are associated with this type of mutation • Inversion • a section of a chromosome that has reversed its orientation • no gain or loss of genetic information, but may disrupt a gene

  8. Causes of Genetic Mutations • Spontaneous mutations • a mutation occurring as a result of errors made during DNA replication. • Induced Mutations • a mutation caused by a chemical agent or radiation (UV radiation, X-rays, etc) • a chemical agent that causes a mutation is a mutagenic agent • a chemical agent that causes cancer is a carcinogen.

  9. Cancer • cancer is considered a genetic disorder because it is always associated with a mutation in the genetic sequence. • in percentage here is the risk factors related to cancer. • 32% smoking • 30% diet • 10% viruses • 7% STDs (STIs) • 10% environmental • 3% alcohol • 2% food additives • 1% sunlight • 5% unknown Homework: Read the case study on page 689-690 and answer questions 1-6, due Monday Nov 29

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