2. BELL WORK

3. Monday Bell Work Pick a New Seat – Your Choice! Please put out Outline for grading!

4. Current Event Complete the following tasks: 1.Read the Current Event – Tanning Mom 2.Answer the Questions – Found on Back of Sheet

5. Image: http://www.seop.yale.edu/imgs/mitosis.jpg ABCDE Answer the questions using the cell images shown below. 1. What type of cell is shown in the pictures above? Plant or Animal 2. Which cell is in the first phase of cell division? _____ 3. Which cell is in anaphase? _____ 4. What stage is shown in cell A? ______________ 5. Which stage is shown in cell B? _______________ 6. List the cells in the order they occur in cell division. ___  ___  ___  ___  ____

6. ABCDE 1. What type of cell is shown in the pictures above? Plant or Animal 2. Which cell is in the first phase of cell division? _____ 3. Which cell is in anaphase? _____ 4. What stage is shown in cell A? ______________ 5. Which stage is shown in cell B? _______________ 6. List the cells in the order they occur in cell division. ___  ___  ___  ___  ____ The answers are … PROPHASE C A EA DCB TELOPHASE

7. Current Event Complete the following tasks: 1.Read the Current Event – New Chemistry May Cure Human Cancers 2.Answer the Questions – What facts about cells did scientists use to design their treatment – How did it work?

9. Week of April 21, 2014 Monday – BioFlix Mitosis Tuesday/Wednesday – Lecture: Meiosis – Lab: Cell Cycle/Cancer Lab Thursday – Karyotyping Friday – Vocabulary Quiz – Bioflix Meiosis Activity

10. HOMEWORK Week of April 21, 2014

11. Week of April 21, 2014 Week of April 21, 2014 Vocabulary Words – All Chapter 8 – Quiz: Friday, April 25 Textbook Reading – Sections 8.12 to 8.24 – Outline Notes, Due: Friday, April 25 MP3 Recording – Meiosis – Listen to Recording – Take Quiz and Print for Credit – Put in Folder Folders – Complete: Test Day!

12. Friday, April 25, 2014 MP3 Recording – Meiosis – Mitosis Comparison – Listen to Recording – Take Quiz and Print for Credit – Put in Folder BioFlix – Finish – Place in Folder Folders – Complete – after Karyotyping Lab next week

13. Friday Agenda Vocabulary Quiz Vocabulary Quiz BioFlix Meiosis BioFlix Meiosis –Animation –Tutorials –Worksheet Absent? Absent? –See Me for Details

14. Tennessee Became a State?16 th How Big? 42, 146 square miles (36 th biggest) Population? 6,495,978 (17 th most populous)

15. White Bellted Galloway

18. Meiosis Basic Notes Just Add Note Cards

19. Organisms that reproduce Sexually are made up of two different types of cells. 1.Somatic Cells are “body” cells and contain the normal number of chromosomes ….called the “Diploid” number (the symbol is 2n ). Examples would be … skin cells, brain cells, etc. 2.Gametes are the “sex” cells and contain only ½ the normal number of chromosomes…. called the “Haploid” number (the symbol is n )….. Sperm cells and ova are gametes. n = number of chromosomes in the set… so….2n means 2 chromosomes in the set…. Polyploid cells have more than two chromosomes per set… example: 3n (3 chromosomes per set)

20. Flashcard Somatic Cells: Body Cells = 2n example: skin cells Gametes: Sex Cells = n example: sperm or ova n = number of chromosomes in a set 2n = 2 chromosomes in a set

21. Flashcard Diploid: 2n = 2 sets of chromosomes Haploid: n = set of chromosomes Polyploid: more than 2 sets of chromosomes n = number of chromosomes in a set 2n = 2 chromosomes in a set

22. Gametes The Male Gamete is the Sperm and is produced in the male gonad the Testes. The Female Gamete is the Ovum (ova = pl.) and is produced in the female gonad the Ovaries.*Flashcard

23. Meiosis cell divisiongametes, half chromosomes,The form of cell division by which gametes, with half the number of chromosomes, are produced. Diploid (2n)  haploid (n) Diploid (2n)  haploid (n) Meiosissexual reproduction. Meiosis is sexual reproduction. Two divisionsmeiosis I meiosis II Two divisions ( meiosis I and meiosis II ).

24. Meiosis in males is called spermatogenesis and produces sperm. Meiosis in males is called spermatogenesis and produces sperm. Meiosis in females is called oogenesis and produces ova. Meiosis in females is called oogenesis and produces ova.*Flashcard

25. Spermatogenesis 2n=46 diploid (2n) n=23 meiosis I n=23 sperm haploid (n) meiosis II 4 sperm cells are produced from each primary spermatocyte. Primary Spermatocyte Secondary Spermatocyte

26. Oogenesis *** The polar bodies die… only one ovum (egg) is produced from each primary oocyte.

27. Fertilization spermeggzygoteThe fusion of a sperm and egg to form a zygote. A zygote is a fertilized egg n=23 egg sperm n=23 2n=46 zygote

28. Meiosis – mouse testes Parent cell 4 gametes 1 st division 2 nd division

29. During Ovulation the ovum is released from the ovary and transported to an area where fertilization, the joining of the sperm and ovum, can occur…… fertilization, in Humans, occurs in the Fallopian tube. Fertilization results in the formation of the Zygote. (fertilized egg) Sperm + Ovum (egg) Zygote fertilization

30. Meiosis Sex cells gametes(sperm or egg) Sex cells divide to produce gametes (sperm or egg). Gameteshalfchromosomes Gametes have half the # of chromosomes. Occurs only in gonads (testes or ovaries). Occurs only in gonads (testes or ovaries). Male: spermatogenesis Female: oogenesis Meiosismitosis Meiosis is similar to mitosis with some chromosomal differences.

32. Why do we need meiosis? Meiosis is necessary to halve the number of chromosomes going into the sex cells Meiosis is necessary to halve the number of chromosomes going into the sex cells Why halve the chromosomes in gametes? At fertilization the male and female sex cells will provide ½ of the chromosomes each – so the offspring has genes from both parents At fertilization the male and female sex cells will provide ½ of the chromosomes each – so the offspring has genes from both parents

33. Meiosis – A Source of Distinction Why do you share some but not all characters of each parent? What are the rules of this sharing game? At one level, the answers lie in meiosis.

34. Meiosis does two things - 1) Meiosis takes a cell with two copies of every chromosome (diploid) and makes cells with a single copy of every chromosome (haploid). This is a good idea if you’re going to combine two cells to make a new organism. This trick is accomplished by halving chromosome number. In meiosis, one diploid cells produces four haploid cells.

35. 2) Meiosis scrambles the specific forms of each gene that each sex cell (egg or sperm) receives. This makes for a lot of genetic diversity. This trick is accomplished through independent assortment and crossing-over. Genetic diversity is important for the evolution of populations and species.

36. Meiosis Parent cell – chromosome pair Chromosomes copied 1 st division - pairs split 2 nd division – produces 4 gamete cells with ½ the original no. of chromosomes

37. Meiosis – mouse testes Parent cell 4 gametes 1 st division 2 nd division

38. THE STAGES OF MEIOSIS: Reduction Division

40. Meiosis I : Separates Homologous Chromosomes Interphase Interphase – Each of the chromosomes replicate – The result is two genetically identical sister chromatids which remain attached at their centromeres

41. Interphase I Nucleus Nucleus and nucleolus visible. nuclear membrane nucleolus cell membrane chromatin

42. Prophase I - Synapsis Homologous chromosomes sister chromatids Tetrad

43. Homologous Chromosomes chromosomesmaternalpaternal Pair of chromosomes (maternal and paternal) that are similar in shape and size. (tetrads) Homologous pairs (tetrads) carry genes controlling the same inherited traits. locus(position of a gene) Each locus (position of a gene) is in the same position on homologues. homologous chromosomes. Humans have 23 pairs of homologous chromosomes. autosomes 22 pairs of autosomes sex chromosomes 1 pair of sex chromosomes

44. Homologous Chromosomes PaternalMaternal eye color locus eye color locus hair color locus hair color locus

45. Karyotype A method of organizing the chromosomes of a cell in relation to number, size, and type. A method of organizing the chromosomes of a cell in relation to number, size, and type.

46. Humans have 23 Sets of Homologous Chromosomes Each Homologous set is made up of 2 Homologues. Homologue

47. Autosomes (The Autosomes code for most of the offspring’s traits) In Humans the “Autosomes” are sets 1 - 22

48. Sex Chromosomes The Sex Chromosomes code for the sex of the offspring. ** If the offspring has two “X” chromosomes it will be a female. ** If the offspring has one “X” chromosome and one “Y” chromosome it will be a male. XX chromosome - femaleXY chromosome - male In Humans the “Sex Chromosomes” are the 23 rd set

49. Boy or Girl? The Y Chromosome “Decides” X chromosome Y chromosome

50. Sex Chromosomes “Sex Chromosomes” …….the 23 rd set 23 This person has 2 “X” chromosomes… and is a female.

51. Interphase I Nucleus Nucleus and nucleolus visible. nuclear membrane nucleolus cell membrane chromatin

52. Prophase I This is a crucial phase for mitosis. This is a crucial phase for mitosis. During this phase each pair of chromatids don’t move to the equator alone, they match up with their homologous pair and fasten together (synapsis) in a group of four called a tetrad. During this phase each pair of chromatids don’t move to the equator alone, they match up with their homologous pair and fasten together (synapsis) in a group of four called a tetrad. Extremely IMPORTANT!!! It is during this phase that crossing over can occur. Extremely IMPORTANT!!! It is during this phase that crossing over can occur. Crossing Over is the exchange of segments during synapsis. Crossing Over is the exchange of segments during synapsis.

53. Prophase I centrioles spindle fiber aster fibers

54. Metaphase I The chromosomes line up at the equator attached by their centromeres to spindle fibers from centrioles. The chromosomes line up at the equator attached by their centromeres to spindle fibers from centrioles. – Still in homologous pairs

55. Metaphase I metaphase plate OR metaphase plate

56. Anaphase I The spindle guides the movement of the chromosomes toward the poles The spindle guides the movement of the chromosomes toward the poles – Sister chromatids remain attached – Move as a unit towards the same pole The homologous chromosome moves toward the opposite pole The homologous chromosome moves toward the opposite pole – Contrasts mitosis – chromosomes appear as individuals instead of pairs (meiosis)

57. Anaphase I

58. Telophase I This is the end of the first meiotic cell division. This is the end of the first meiotic cell division. The cytoplasm divides, forming two new daughter cells. The cytoplasm divides, forming two new daughter cells. Each of the newly formed cells has half the number of the parent cell’s chromosomes, but each chromosome is already replicated ready for the second meiotic cell division Each of the newly formed cells has half the number of the parent cell’s chromosomes, but each chromosome is already replicated ready for the second meiotic cell division

59. Cytokinesis Occurs simultaneously with telophase I Occurs simultaneously with telophase I – Forms 2 daughter cells Plant cells – cell plate Plant cells – cell plate Animal cells – cleavage furrows Animal cells – cleavage furrows NO FURTHER REPLICATION OF GENETIC MATERIAL PRIOR TO THE SECOND DIVISION OF MEIOSIS NO FURTHER REPLICATION OF GENETIC MATERIAL PRIOR TO THE SECOND DIVISION OF MEIOSIS

60. Telophase I

62. Meiosis II : Separates sister chromatids Proceeds similar to mitosis Proceeds similar to mitosis THERE IS NO INTERPHASE II ! THERE IS NO INTERPHASE II !

63. Prophase II prophasemitosissame as prophase in mitosis

64. Metaphase II metaphasemitosissame as metaphase in mitosis metaphase plate

65. Anaphase II anaphasemitosissame as anaphase in mitosis sister chromatids separate sister chromatids separate

66. Telophase II telophasemitosisSame as telophase in mitosis. Nuclei form. Cytokinesis Cytokinesis occurs. Remember:four haploid daughter cells produced. Remember:four haploid daughter cells produced. gametes = sperm or egg

67. Telophase II

68. Prophase II Each of the daughter cells forms a spindle, and the double stranded chromosomes move toward the equator Each of the daughter cells forms a spindle, and the double stranded chromosomes move toward the equator

69. Metaphase II The chromosomes are positioned on the metaphase plate in a mitosis- like fashion The chromosomes are positioned on the metaphase plate in a mitosis- like fashion

70. Anaphase II The centromeres of sister chromatids finally separate The centromeres of sister chromatids finally separate The sister chromatids of each pair move toward opposite poles The sister chromatids of each pair move toward opposite poles – Now individual chromosomes

71. Telophase II and Cytokinesis Nuclei form at opposite poles of the cell and cytokinesis occurs Nuclei form at opposite poles of the cell and cytokinesis occurs After completion of cytokinesis there are four daughter cells After completion of cytokinesis there are four daughter cells – All are haploid (n)

73. One Way Meiosis Makes Lots of Different Sex Cells (Gametes) – Independent Assortment Independent assortment produces 2 n distinct gametes, where n = the number of unique chromosomes. That’s a lot of diversity by this mechanism alone. In humans, n = 23 and 2 23 = 6,000,0000.

75. Another Way Meiosis Makes Lots of Different Sex Cells – Crossing-Over Crossing-over multiplies the already huge number of different gamete types produced by independent assortment.

77. The Key Difference Between Mitosis and Meiosis is the Way Chromosomes Uniquely Pair and Align in Meiosis Mitosis The first (and distinguishing) division of meiosis

79. Boy or Girl? The Y Chromosome “Decides” X chromosome Y chromosome

80. Boy or Girl? The Y Chromosome “Decides”

81. ANY QUESTIONS?

82. EXTRA SLIDES

83. Meiosis – division error Chromosome pair

84. Meiosis error - fertilization Should the gamete with the chromosome pair be fertilized then the offspring will not be ‘normal’. In humans this often occurs with the 21 st pair – producing a child with Downs Syndrome

85. 21 trisomy – Downs Syndrome Can you see the extra 21 st chromosome? Is this person male or female?