1. Fig. 13-2a (a) Hydra 0.5 mm Bud Parent

3. DNA – lots of it in a small space chromatin Chromosome Know how to label

4. Fig. 12-UN3

5. Fig. 12-14 S G1G1 M checkpoint G2G2 M Control system G 1 checkpoint G 2 checkpoint Cyclins are proteins that control the cell cycle. They create chemical “checkpoints” through- out the process.

6. Fig. 12-UN1 Telophase and Cytokinesis Anaphase Metaphase Prometaphase Prophase MITOTIC (M) PHASE Cytokinesis Mitosis S G1G1 G2G2

7. Fig. 12-9 Cleavage furrow 100 µm Contractile ring of microfilaments Daughter cells (a) Cleavage of an animal cell (SEM)(b) Cell plate formation in a plant cell (TEM) Vesicles forming cell plate Wall of parent cell Cell plate Daughter cells New cell wall 1 µm

8. What is the haploid number for each? Symbol for haploid? What kind of cells are haploid?

9. Fig. 13-3 APPLICATION TECHNIQUE Pair of homologous replicated chromosomes 5 µm Centromere Sister chromatids Metaphase chromosome The process of creating a graphic display of chromosomes from a cell to determine abnormal chromosome number. Homologues are paired up and arranged in descending order according to length.

10. Fig. 13-4 Key Maternal set of chromosomes (n = 3) hapolid # Paternal set of chromosomes (n = 3) 2n = 6 Diploid number Centromere Two sister chromatids of one replicated chromosome Two nonsister chromatids in a homologous pair Pair of homologous chromosomes (one from each set)

11. Fig. 13-5 Key Haploid (n) Diploid (2n) Haploid gametes (n = 23) Egg (n) Sperm (n) MEIOSISFERTILIZATION Ovary Testis Diploid zygote (2n = 46) Mitosis and development Multicellular diploid adults (2n = 46) The relationship between mitosis and meiosis

12. Fig. 13-12-5 Prophase I of meiosis Homologous pair Nonsister Chromatids Centromere Anaphase I Anaphase II Daughter cells Recombinant chromosomes TEM

13. Fig. 13-9a MITOSIS MEIOSIS MEIOSIS I Prophase I Chromosome replication Homologous chromosome pair Chromosome replication 2n = 6 Parent cell Prophase Replicated chromosome Metaphase Metaphase I Anaphase I Telophase I Haploid n = 3 Daughter cells of meiosis I MEIOSIS II Daughter cells of meiosis II n n n n 2n2n 2n2n Daughter cells of mitosis Anaphase Telophase

14. Fig. 13-9b SUMMARY Meiosis Mitosis Property DNA replication Number of divisions Occurs during interphase before mitosis begins One, including prophase, metaphase, anaphase, and telophase Synapsis of homologous chromosomes Does not occur Number of daughter cells and genetic composition Two, each diploid (2n) and genetically identical to the parent cell Role in the animal body Enables multicellular adult to arise from zygote; produces cells for growth, repair, and, in some species, asexual reproduction Occurs during interphase before meiosis I begins Two, each including prophase, metaphase, anaphase, and telophase Occurs during prophase I along with crossing over between nonsister chromatids; resulting chiasmata hold pairs together due to sister chromatid cohesion Four, each haploid (n), containing half as many chromosomes as the parent cell; genetically different from the parent cell and from each other Produces gametes; reduces number of chromosomes by half and introduces genetic variability among the gametes

15. Fig. 13-UN3 DNA replication Meiosis I – PMAT to separate homologous pairs. Have 2 cells. Meiosis II – before it starts, NO DNA replication. PMAT separates sister chromatids. Four haploid cells produced. No pairs of chromosomes.

16. Fig. 13-UN4

17. NONDISJUCTION Failure of a particular chromosome to separate properly during meiosis. Can happen in meiosis I if a particular homologous pair fails to separate. Can happen in meiosis if sister chromatids of a particular chromosome fail to separate Remember the term nondisjunction applies to abnormal gametes. In humans, abnormal egg or sperm would be 24 or 22 chromosomes.

18. Fig. 15-13-3 Meiosis I Nondisjunction (a) Nondisjunction of homologous chromosomes in meiosis I (b) Nondisjunction of sister chromatids in meiosis II Meiosis II Nondisjunction Gametes Number of chromosomes n + 1 n – 1 nn

19. Aneuploidy results from the fertilization of a gamete in which nondisjunction occurred Offspring with this condition have an abnormal number of a particular chromosome REMEMBER – aneuploidy means abnormal number of a particular chromosome in a ZYGOTE (FERTILIZATION HAS HAPPENED). We are not discussing the gamete any more. Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

20. Two types of aneuploidy: Monosomy: A monosomic zygote has only one copy of a particular chromosome. In humans an example would be Turner’s syndrome: Female child only has only 1 sex chromosome (X) in each diploid cell instead of XX, she has a total of 45 chromosomes in diploid cells instead of 46. Trisomy: A trisomic zygote has three copies of a particular chromosome. In humans an example would be Down’s Syndrome: Child has 3 copies of chromosome 21 in all diploid cells for a total of 47. Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

21. Another Trisomic disorder Patau Syndrome (Trisomy 13) cleft palate fetuses with this condition rarely to go to term so it occurs in only 1 in 6000 live births It is rare for babies to survive for very long if liveborn because of the multitude of anomalies atrial septal defect inguinal hernia polydactyly of hands and feet Sometimes cyclopia or absence of eyes

22. Patau Syndrome (Trisomy 13)

23. Edward Syndrome (Trisomy 18) Sometimes due to translocation Survival rate of Edwards Syndrome is very low Approximately 95% die in utero. Of liveborn infants, only 50% live to 2 months, and only 5–10% will survive their first year of life. The median life span is five to fifteen days One percent of children born with this syndrome live to age ten, typically in cases of the less severe Edwards syndrome. heart defects at birth intestines protruding outside the body Feeding and breathing difficulties Microcephaly Clenched fists

24. Polyploidy is a condition in which an organism has more than two complete sets of chromosomes – Triploidy (3n) is three sets of chromosomes – Tetraploidy (4n) is four sets of chromosomes Polyploidy is common in plants, but not animals Polyploids are more normal in appearance than aneuploids Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

26. Down Syndrome (Trisomy 21) Down syndrome is an aneuploid condition that results from three copies of chromosome 21 It affects about one out of every 700 children born in the United States The frequency of Down syndrome increases with the age of the mother, a correlation that has not been explained Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

27. Fig. 15-16a

28. Fig. 15-16b

29. 2 processes for collecting fetal cells for karyotyping.

30. Aneuploidy of Sex Chromosomes Nondisjunction of sex chromosomes produces a variety of aneuploid conditions Klinefelter syndrome is the result of an extra chromosome in a male, producing XXY individuals Monosomy X, called Turner syndrome, produces X0 females, who are sterile; it is the only known viable monosomy in humans Poly X – 3 copies of XXX Jacob Syndrome - XYY Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

31. Almost all (95%) have Short stature Loss of ovarian function Caused by the absence of a set of genes from the short arm of one X chromosome 1 out of every 2,000-2,500 female live births Single X chromosome 75-80% single X is contributed by mother X-O = Female (Turner Syndrome) X-X-Y=Male (Klinefelter Syndrome) Appearance Short stature Absent adolescent growth spurt Average adult height is 4 feet 8 inches Loss of SHOX gene necessary for growth of long bones Short fingers (4 th metacarpal) Newborns – puffy, bulbous hands and feet

33. Alterations of Chromosome Structure Breakage of a chromosome can lead to four types of changes in chromosome structure: – Deletion removes a chromosomal segment – Duplication repeats a segment – Inversion reverses a segment within a chromosome – Translocation moves a segment from one chromosome to another Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

34. Fig. 15-15 Deletion A B C D E F G HA B C E F G H (a) (b) (c) (d) Duplication Inversion Reciprocal translocation A B C D E F G H A B C B C D E F G H A D C B E F G H M N O C D E F G H M N O P Q RA B P Q R

35. Disorders Caused by Structurally Altered Chromosomes The syndrome cri du chat (“cry of the cat”), results from a specific deletion in chromosome 5 A child born with this syndrome is mentally retarded and has a catlike cry; individuals usually die in infancy or early childhood Certain cancers, including chronic myelogenous leukemia (CML), are caused by translocations of chromosomes Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings