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Genetics

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  1. Genetics

  2. The two major groups of specialized cells in your body are _______ and ________. • Somatic cells and germ cells

  3. ______ cells, also called body cells, make up most of your body tissues and organs. • Somatic cells

  4. DNA is passed on to offspring by ____ ___. • Germ cells

  5. Gametes are ____ cells. • sex

  6. Each species has a characteristic number of ______ per cell. • chromosomes

  7. Chromosome number does not seem to be related to the _______ of an organism. • complexity

  8. Humans have ___ chromosomes in ___ pairs. • 46, 23

  9. Humans receive 23 chromosomes from the _____ and 23 from the _____. • Mother, father

  10. In humans, each pair of chromosomes is referred to as a ________ ____. • Homologous pair

  11. Homologous means……. • Having the same structure

  12. A number has been assigned to each homologous pair, ordered from _____ to _____. • Largest to smallest

  13. Chromosome pairs 1-22 make up your ______. • autosomes

  14. These chromosomes are not directly related to the sex of an organism. • autosomes (1-22)

  15. The two human sex chromosomes are __ and __. • x and y

  16. An organism with two X chromosomes is _____. • female

  17. An organism with one X chromosome and one Y chromosome is ____. • male

  18. X and Y chromosomes are not _______. • homologous

  19. The ____ chromosome is larger and contains numerous genes. • X

  20. ______ _______ involves the fusion of two gametes that results in offspring that are a genetic mixture of both parents. • Sexual reproduction

  21. The actual fusion of an egg and sperm cell is called _______. • fertilization

  22. When fertilization occurs, the nuclei of the egg and sperm cell fuse to form one _____. • nucleus

  23. Egg and sperm cells only have half the usual number of ______. • chromosomes

  24. Body cells are ____, meaning that a cell has two copies of each chromosome. • diploid

  25. Gamete cells are _____, meaning that one cell has one copy of each chromosome. • haploid

  26. The sex of an individual is determined by the _____. • Male (for humans)

  27. Increasing the number of sets of chromosomes can give rise to a new _____. • species

  28. 4 copies of each chromosome. • A condition called tetraploidy

  29. Germ cells in human reproductive organs undergo _____ to form gametes. • meiosis

  30. ______ is a form of nuclear division that divides a diploid cell into haploid cells. • meiosis

  31. ______ is a type of cell division that occurs in body cells. • Mitosis

  32. What are some of the differences between mitosis an meiosis? • In mitosis, DNA is copied once and divided once. In meiosis, DNA is copied once but divided twice. • In mitosis, daughter cells are genetically identical to the parent cell. Meiosis makes genetically unique haploid cells from a diploid cell. • Mitosis is used for growth, development, and repair. Takes place throughout life. Meiosis, however, takes place only at certain times. • Mitosis is involved in asexual reproduction, meiosis is involved in sexual reproduction.

  33. Where are germ cells located in the human body? • Ovaries and testes • What is the difference between an autosome and a sex chromosome? • Autosomes, chromosomes 1-22, are not directly related to the sex of an organism.

  34. Is the cell that results from fertilization a haploid or diploid cell? Explain. • Each cell has only one copy of each chromosome. It takes the combination of an egg and sperm cell to make the 46 human chromosomes…..so haploid.

  35. Does meiosis or mitosis occur more frequently in your body? • Mitosis, it is responsible for growth, development, and repair. • Meiosis is responsible for reproduction.

  36. _______ is a form of nuclear division that creates four haploid cells from one diploid cell. • Meiosis • Meiosis _______ chromosome number and creates genetic _________. • reduces,diversity

  37. Each half of a duplicated chromosome is called a ________. • Chromatid • ______ ______ are the duplicated chromosomes that remain attached by the centromere. • Sister Chromatids

  38. ______ ______ are divided during meiosis I. ____ ______ are not divided until meiosis II. • Homologous chromosomes • Sister chromatids

  39. Before meiosis begins, _______ has already been copied. • DNA • What are the 4 stages of meiosis I? • Prophase I • Metaphase I • Anaphase I • Telophase I

  40. Identify the phase in meiosis I. • The nuclear membrane breaks down centrosomes and centioles move to opposite sides of the cell. Spindle fibers assemble Homologous chromosomes pair up • Prophase I

  41. Identify the phase in Meiosis I • Homologous chromosome pairs are randomly lined up along the middle of the cell by spindle fibers. • Metaphase I

  42. Identify the phase in Meiosis I • Paired homologous chromosomes separate and move to opposite sides of the cell. • Anaphase I

  43. Identify the phase in Meiosis I • The nuclear membrane forms, the spindle fibers disassemble, and the cell undergoes cytokinesis. • Telophase I

  44. Identify the phase in Meiosis II • The nuclear membrane breaks down, centrosomes and centrioles move to opposite sides of the cell, spindle fibers assemble. • Prophase II

  45. Identify the phase in Meiosis II • Spindle fibers align the 23 chromosomes at the cell equator • Metaphase II

  46. Identify the phase in Meiosis II • The sister chromatids are pulled apart from each other and move to opposite sides of the cell. • Anaphase II

  47. Identify the phase of Meiosis II • Nuclear membranes form around each set of chromosomes at opposite ends of the cell, spindle fibers break apart, the cell undergoes cytokinesis, and four haploid cells are produced. • Telophase II

  48. What is the major difference between Metaphase I and Metaphase II? • In metaphase I, pairs of homologous chromosomes line up at the equator. In metaphase II, the chromosomes are not paired.

  49. What is the major difference between Anaphase I and Anaphase II? • Sister chromatids remain together in Anaphase I but separate in Anaphase II.

  50. ___________ is the production of gametes. • Gametogenesis