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Bell Ringer: Copy the following words to define for homework.

Bell Ringer: Copy the following words to define for homework. Carrier Pedigree Autosome Codominance Incomplete Dominance Multiple Alleles Sex Chromosome Sex-Linked Trait Karyotype Nondisjunction Telomere Deletion Inversion Translocation Down Syndrome Turner’s Syndrome

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Bell Ringer: Copy the following words to define for homework.

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  1. Bell Ringer: Copy the following words to define for homework. • Carrier • Pedigree • Autosome • Codominance • Incomplete Dominance • Multiple Alleles • Sex Chromosome • Sex-Linked Trait • Karyotype • Nondisjunction • Telomere • Deletion • Inversion • Translocation • Down Syndrome • Turner’s Syndrome • Klinefelter’s Syndrome

  2. Benchmark Test Info • Point Breakdown • 52 pts Participation • 48 pts (2pts each) for the 24 questions we’ve already covered. • TALKING/LOOKING AROUND will result in the loss of your 52 participation points.

  3. Bell-Ringer • Grab a packet of guided notes from the back table.

  4. Complex Inheritanceand Human Heredity 11

  5. The Big Idea • Human inheritance does not always follow Mendel’s laws.

  6. Main Idea #1 • The inheritance of a trait over several generations can be shown in a pedigree.

  7. Recessive Genetic Disorders • Remember - recessive traits can be masked by a dominant trait. • Therefore, a person who is heterozygous for a characteristic may be considered acarrierfor that trait since it will not be expressed. • Even though a carrier is not affected by the trait, they can pass the trait on to future generations. • In order for the recessive trait to show in the individual, the person must be homozygous recessive.

  8. Common Recessive Disorders • Cystic Fibrosis • Affects the mucus-producing glands, digestive enzymes, and sweat glands • Chloride ions are not absorbed into the cells of a person with cystic fibrosis but are excreted in the sweat • Without sufficient chloride ions in the cells, a thick mucus is secreted • The mucus clogs ducts in the pancreas, causes problems with digestion, and blocks some of the tiny passages in the respiratory system.

  9. Common Recessive Disorders • Albinism • Caused by altered genes, resulting in the absence of melanin (color pigment) in the hair and eyes • Common characteristics include: white hair, very pale skin, and pink pupils • Tay-Sachs Disease • Caused by the absence of an enzyme responsible for breaking down fatty acids • The fats begin accumulating in the brain, destroying brain cells and mental deterioration.

  10. Dominant Genetic Disorders • Some genetic disorders are controlled by a dominant allele. • People who have only one copy of this allele will display the trait. Only those who are homozygous recessive will not have the disorder. • Huntington’s Disease • Disease that gradually destroys the nervous system. Symptoms usually begin between the ages of 30 and 50. • Achondroplasia • Genetic condition that causes small body size and limbs that are comparatively short. This is the most common form of dwarfism.

  11. Pedigrees • Apedigreeis a diagram that traces the inheritance of a particular trait through several generations. • Males are represented by squares, and females by circles. • One who is affected by the trait will have a symbol that is colored in, while those that are unaffected by the trait will have an unfilled symbol.

  12. Pedigree

  13. Let’s Practice!!! • Make this correction: • Second question for #3 should read, What are the sexes of the children?

  14. Main Idea #3 • Chromosomes can be studied using karyotypes.

  15. Karyotypes • Akaryotypeis a picture of a person’s chromosomes. • Chromosomes are taken from the stage of metaphase and stained. • They are then placed in order of decreasing size. The last pair is the sex chromosome pair. • Disorders caused by an incorrect number of chromosomes or malformed chromosomes are the easiest to identify using a karyotype.

  16. Normal Karyotypes

  17. Telomeres • Telomerecaps consist of DNA associated with proteins.

  18. Nondisjunction • Homologous chromosomes separate during the final steps of meiosis to ensure that each developing sperm or egg receives one copy of each chromosome. • Nondisjunctionis the failure of a pair of homologous chromosomes to separate properly. • Resulting sex cells will either have an extra chromosome (trisomy) or a missing chromosome (monosomy).

  19. Down Syndrome • One of the most common disorders due to nondisjunction is Down syndrome, also known as trisomy 21. • Down syndrome occurs when the person has a third copy of the 21st chromosome. • Common features include: short stature, heart defects, distinctive facial features, and mental disability.

  20. Disorders Due to Nondisjunction of Sex Chromosomes Klinefelter Syndrome (XXY) Jacob’s Syndrome (XYY) Trisomy X Syndrome (XXX) Turner’s Syndrome (XO)

  21. Types of Mutations • Mutations can involve an entire chromosome or a single DNA nucleotide, and they may take place in any cell. • Germ-cell mutationsoccur in an organism’s gametes (germ cells). • These do not affect that organism, but may be passed on to their offspring the germ cell becomes fertilized. • Somatic mutationsoccur in an organism’s body cells and can affect the organism. • These mutations cannot be passed on to offspring. • Some examples include skin cancer and leukemia. • Lethal mutationscause death, usually before birth.

  22. Chromosome Mutations • Deletion(1)- results in the loss of a piece of chromosome due to the breakage of that chromosome; genetic information will be lost • Duplication(2)- results in the copying of a segment of the chromosome • Inversion(3)- a segment of a chromosome breaks off and reattaches itself to the chromosome in a reversed order

  23. Chromosome Mutations • Insertion(1) - a segment of a chromosome breaks off and reattaches itself to another homologous chromosome • Translocation(2) - segments of chromosomes break off and exchange places on different chromosomes

  24. Chromosome Mutations • Nondisjunctionis also a type of chromosome mutation. It affects the total number of chromosomes instead of pieces of individual chromosomes.

  25. Bell-Ringer Copy your homework for the week! 1/13 – 1/17 Homework: Monday: Chapter 11 Assessment pg. 319-321 1-30 Omit #s 11, 16, 18, 19, 20, 27, 28 Tuesday: STUDY FOR TEST Wednesday: Ch. 12 Vocab BRING YOUR BOOK THURSDAY Thursday: Finish Ch. 12 Guided Reading Friday: NONE

  26. Genetic Disorder Foldable • Achondroplasia • Albinism • Cystic Fibrosis • Down Syndrome • Huntington’s Disease • Klinefelter Syndrome • Sex-Linked • Tay-Sachs • Turner’s Syndrome Tell if the listed disorders are dominant or recessive and give a brief description of each. For Sex-Linked describe the two that we discussed in class.

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