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Warm-up

Feb. 26, 2013 Topic: mutations. Warm-up. What do you think a mutation is? What can cause a mutation?. Objective. SWBAT explain what a genetic mutation is, list the types of mutations and explain if they are good or bad and why. Today. Introduction to mutations Define

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Warm-up

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  1. Feb. 26, 2013 Topic: mutations Warm-up • What do you think a mutation is? • What can cause a mutation?

  2. Objective • SWBAT explain what a genetic mutation is, list the types of mutations and explain if they are good or bad and why.

  3. Today • Introduction to mutations • Define • Explain the types of mutations • Activity: Mutation by Analogy

  4. Up and Coming…………. Unit Test: Tues. March 5 DNA structure and Function RNA structure and Function Protein Synthesis Mutations

  5. Mutations Mutations mutations

  6. A mutation is a sudden change in the structure or amount of genetic material. + =

  7. II. Chromosomal Mutation –Abnormal change in the structure in all or part of a chromosome or in the number of chromosomes

  8. How to visualize/determine a chromosomal mutation Karyotyping – examining a person’s genetic make-up A. A cell undergoing mitosis is photographed B. Amniocentesis – withdrawing amniotic fluid and cells of a fetus to test for disease C. Arranged by size and location of the centromere.

  9. Replicated chromosomes In metaphase of mitosis Paired with homolog, arranged by size, shape

  10. Female

  11. A B C D E F G A B C D E F G X Y Z • Changes in chromosome structure (most cells die if this happens) 1. Translocation – transfer of part of a chromosome to a non-homologous chromosome NORMAL CHROMOSOME TRANSLOCATION

  12. a. Burkitt’s lymphoma – cancer of the immune system. A child with Burkitt’s Lymphoma (tumors of lymphocytes)

  13. A B C D E F G A BE D CF G 2. Inversion – A piece of the chromosome is rotated NORMAL CHROMOSOME INVERSION

  14. Inversion of human andchimp DNA of chromosome #5

  15. A B C D E F G A B C A B C D E F G 3. Addition – A piece of the chromosome breaks off and attaches to the homologous chromosome NORMAL CHROMOSOME ADDITION

  16. A B C D E F G A B C F G 4. Deletion – A piece of the chromosome breaks off NORMAL CHROMOSOME DELETION

  17. a. Cri-du-chat syndrome – loss of part of chromosome #5. A child with Cri-du-chat syndrome. Symptoms are stomach, intestinal, and heart problems as well as mental retardation.

  18. Nondisjunction – addition or loss of a whole chromosome 1. Occurs during meiosis 2. Trisomy 21 – extra chromosome #21 is Down’s Syndrome.

  19. 3. Klinefelter Syndrome - XXY sex chromosomes A male with a few Feminine features

  20. 4. Turner Syndrome - only one X sex chromosome A female with prepubescent features, cannot have children

  21. C. Polyploidy – some multiple of the normal chromosome number 1. Happens during mitosis or meiosis 2. Results in 3n, 4n, even 5n 3. Plants and fruits grow larger than normal 4. This can be beneficial to farmers and plant breeders *Strawberries….remember the DNA *Animals can not have polyploidy and survive!

  22. Gene mutations – changes in the sequence of DNA or RNA strands A. Point mutations – only one nucleotide has been changed 1. Adding or deleting one nucleotide changes all the codons after the point in the sequence

  23. normal DNA TAC CCG TAT AUG GGC AUA Met Gly Iso mutation TAC ACC GTA T (addition) AUG UGG CAU A Met Try His - Mutation TAC CGT AT (deletion) AUG GCA UA Met Ala -

  24. 2. One base is substituted for another in DNA changes the mRNA sequence and the protein that is formed normal DNA TAC CCG TAT AUG GGC AUA Met Gly Iso Substitution TAC CGG TAT AUG GCC AUA Met Ala Iso

  25. Sickle cell anemia is caused by a change in one base pair and red blood cells are deformed. (substitution)

  26. 3. Silent mutation- sometimes a mutation still codes for the same amino acid. It does not affect the organism. normal DNA TAC CCG TAT AUG GGC AUA Met Gly Iso Substitution TAC CCC TAT AUG GGG AUA Met Gly Iso

  27. 4. Nonsense mutation-nucleotide changed results in a stop codon causing translation to stop prematurely normal DNA TAC CCG TAT AUG GGC AUA Met Gly Iso addition TAC ATC CCT AT AUG UAG GGA UA Met Stop - -

  28. Mutations in what cells do what? 1. Mutations in a single body cell may cause the cell to die 2. Mutations in sex cells – pass along the mutation to the offspring

  29. Advantages to mutations • Sources of new base sequences • A force for natural selection (survival of the fittest, passing on traits that help an organism survive) • Add to genetic diversity

  30. Activity • Mutation by Analogy…….begin and complete for HW

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