1 / 34

Understanding Sexual Reproduction and Chromosome Changes

Explore the creation of sex cells, chromosome processes in meiosis, and the significance of genetic diversity. Engage with gametes, mitosis, and meiosis phases. Dive into the world of chromosomes!

eembry
Download Presentation

Understanding Sexual Reproduction and Chromosome Changes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Aim: How are sex cells created? • Homework: Castle learning & Textbook due FRIDAY

  2. DO NOW: The diagram below includes information on asexual reproduction. Asexual Reproduction • Which term belongs in the are labeled X? • Graphing c. Cutting • Regeneration d. Sporulation Vegetative Propagation Binary Fission Budding X Bread Mold Potato Ameba Hydra

  3. How many chromosomes will be found in each of the two new cells formed as a result of mitotic cell division? • Only one-half as many chromosomes as the parent cell • Twice as many chromosomes as the parent cell • Three times as many chromosomes as the parent cell • The same number as chromosomes as the parent cell

  4. The diagram below represents a microscopic structure observed during cell division • What part of the structure are indicated by arrows A, B and C respectively? B Centromere Chromosome A C Chromotid

  5. Meiosis and Sexual Reproduction

  6. A. Sexual Reproduction • Fusion (joining) of gametes (sex cells) to create an new individual. • There are two parents and two sets of chromosomes. • Offspring inherit traits from both parent

  7. B. Gametes • Male sex cell  Sperm • Female Sex cell Ovum (egg) • Gametes have only 23 chromosomes. This is only half of the number of the parent cell. • Fertilization: the sperm chromosomes join the egg chromosomes. • Together, sperm and egg make a full set of chromosomes.

  8. SEX CELLS • A.K.A. Gametes • Examples: human egg and sperm cells • Function is to fertilize • Used to carry out sexual reproduction • Have _____ chromosomes each 23 MEIOSIS Created by the process of __________

  9. C. Diploid vs. Haploid • DIPLOID: A cell that has a full set of chromosomes . • (Ex.) Somatic cells (body cells) • HAPLOID: A cell that has only half the number of chromosomes. • (Ex.) Gametes (egg and sperm)

  10. Compared to the number of CHROMOSOMES in a normal human body cell, the number in a normalsperm cell is: • The same • Twice as great • Half as great • Four times as great

  11. How many chromosomes will be found in each of the two new cells formed as a result of mitotic cell division? • Only one-half as many chromosomes as the parent cell • Twice as many chromosomes as the parent cell • Three times as many chromosomes as the parent cell • The same number as chromosomes as the parent cell

  12. Aim: How do the chromosomes change during meiosis? Homework: Review book pages pgs. 63-65 p. 66 Q's 11 - 21

  13. DO NOW: How does mitosis effect chromosome number? Example: Human chromosome number is ____ 46 46 Why such a large number? Remember this Is when chromosomes replicate! 92 46 46

  14. Each body cell of a chimpanzee contains 48 chromosomes. How many chromosomes would normally be present in a gamete produced by this chimpanzee? • 24 • 36 • 48 • 96

  15. Homologous Chromosomes Pairs of chromosomes that have genes for the same traits in the same order Chromatid

  16. D. Meiosis • Meiosis: is a process that produces gametes. • Gametes that have half the number of chromosomes. • Separates these homologous chromosomes

  17. MEIOSIS • Meiosis is thetype of cell division by which gamete cells (eggs and sperm) are produced. • Meiosis involves a reduction in the amount of genetic material. • A.K.A. reduction division ???? To maintain normal chromosome number once fertilization occurs 23 23 46

  18. How do the chromosomes change during meiosis? END START 46 23 2n = ____ Called the Diploid # n = ____ Called the Haploid #

  19. Meiosis consists oftwosuccessive nucleardivisionswith onlyoneround of DNAreplication. 46 Parent cell 92 46 46 4 Daughter cells 23 23 23 23

  20. Phases of Meiosis • Meiosis I • Interphase • Prophase • Metaphase • Anaphase • Telophase • Meiosis II • Prophase II • Metaphase II • Anaphase II • Telophase II Why only one Interphase? To reduce chromosome number

  21. Gametogenisis • Is the development of mature sex cells called GAMETES • Formation involves meiosis in immature sex cells. • 2 types: Spermatogenesis and Oogenesis

  22. Gametogenesis After meiosis 4 gamete (sex cells sperm) are produced.

  23. Oogenisis During this step only one viable gamete (sex cell egg) is produced and 3 polar bodies.

  24. Genetic Diversity takes place during fertilization. This is because 23 chromosomes from each gamete are combined during this step!

  25. In humans, the body cells have 46 (2n) chromosomes.Gametes that are produced by meiosis will contain only 23 (n) chromosomes. n n 2n GAMETES n Mother cell n

  26. The exchange of genetic material between • Paternal and Maternal chromosomes • Important for genetic variation Crossing Over

  27. Which process produces cells with more genetic diversity, mitosis or meiosis? Why? • Answer: Meiosis • Mitosis produces daughter cells that are • identical to the mother cells • Meiosis produces daughter cells that are genetically different from the paternal cells • So, there is more diversity (difference) in meiosis

  28. Mitosis Vs. Meiosis

  29. F. Mitosis Vs. Meiosis:

  30. Homologous pairs of chromosomes are NOT normally found in • Zygotes • Body tissue cells • Gametes • Embryonic nerve cells

  31. Meiosis consists oftwosuccessive nucleardivisionswith onlyoneround of DNAreplication. 46 Parent cell 92 46 46 4 Daughter cells 23 23 23 23

  32. DO NOW: Label the phases shown (1-3) 2 1 3

More Related