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Advanced Biology

Advanced Biology. Mutations. What is a mutation? A change (mistake) in the replication of genetic material. The daughter cell is different from the parent. Most replication errors are corrected by the cell’s built in spell check system. However, some do escape detection. Gene Mutation.

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Advanced Biology

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  1. Advanced Biology Mutations

  2. What is a mutation? • A change (mistake) in the replication of genetic material. • The daughter cell is different from the parent

  3. Most replication errors are corrected by the cell’s built in spell check system. • However, some do escape detection

  4. Gene Mutation • Deletion – Leaving out one nucleotide in the sequence, shifts the reading of the sequence to the left, creating a totally different set of amino acids

  5. Gene Mutation • Normal mRNA reads: • AUG AAG UUU GGC GCA UUG UAA • Met Lys Phe Gly Ala Leu Stop. • Mutated mRNA reads: • AUG AAG UUGGCG CAU UGU AA… • Met LysLeu Ala His Cys …

  6. Gene Mutation • Insertion – Mutation in which an extra nucleotide is added to the chain during replication, shifts reading to the right, creating a totally different set of amino acids

  7. Gene Mutation • Normal mRNA reads: • AUG AAG UUU GGC GCA UUG UAA • Met Lys Phe Gly Ala Leu Stop. • Mutated mRNA reads: • AUG AAG UUU GUG CGC AUU GUA A • Met Lys PheVal Arg Ile Val

  8. Gene Mutation • Point Mutation – A base substitution occurs. One nucleotide is replaced with a different one

  9. Gene Mutation • Normal mRNA reads: • AUG AAG UUU GGC GCA UUG UAA • Met Lys Phe Gly Ala Leu Stop. • Mutated mRNA reads: • AUG AAG UUU AGCGCA UUG UAA • Met Lys Phe Ser Ala Leu Stop.

  10. Gene Mutation • These mutations arise spontaneously during DNA replication. • External agents may cause mutations, called mutagens.

  11. Chromosome Mutations • Changes may occur in chromosomes as well as in genes. • Chromosome mutations can have serious effects on the distribution of genes to gametes during meiosis.

  12. Chromosome Mutations • Deletion: • ABCDE---FGH • ABCE---FGH

  13. Chromosome Mutations • Duplication: • ABCDE---FGH • ABCBCDE---FGH

  14. Chromosome Mutations • Inversion: • ABCDE---FGH • ADCBE---FGH

  15. Chromosome Mutations • Attachment to a different chromosome: • ABCDE---FGH • WXY---Z • WXABCDE---FGH • Y---Z

  16. Other causes of genetic variation • During meiosis, homologous pairs fail to separate. • This would cause the offspring to have an extra chromosome.

  17. CANCER • Abnormal cells, go through cell cycle very fast, creating new cells like it. • They reproduce in an uncontrolled way, crowding out healthy cells and destroying tissues and possibly organs. • It can spread to other parts of the body

  18. Causes of Cancer • Genes that control the cell cycle mutate, called an oncogene. • Mutations may be inherited or caused by a carcinogen, a cancer causing agent in the environment. • Tobacco smoke, radiation and other chemicals.

  19. Causes of Cancer • Viruses may also cause cancer. • Their presence disrupts normal cell processes. • They can also carry oncogenes into the host cell.

  20. Technology • Scientists can transfer a gene artificially from a donor organism to a bacteria. • The DNA of the bacterium is called recombinant DNA. • The bacteria will transcribe and translate the foreign gene and produce the protein it is coding for.

  21. Technology • Small, circular pieces of DNA, called plasmids, are where the foreign DNA is placed.

  22. Technology • To obtain a foreign gene, mRNA from a cell is isolated and DNA is produced (called reverse transcription). This single stranded DNA is converted to a double strand and this double strand is the desired gene.

  23. Technology • In use today – goats that produce a human blood clot dissolving factor. • Plants that are disease resistant. • Plants that are larger than normal.

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