1 / 70

Chapter 9

Chapter 9. Cellular Reproduction. All cells come from cells. Reproduction. Asexual: The production of offspring by a single parent. Sexual: The production of offspring by a combination of genetic material from 2 parents. Asexual Reproduction. Binary fission: “Dividing in half”

callista-neumann
Download Presentation

Chapter 9

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. Chapter 9 Cellular Reproduction

  2. All cells come from cells

  3. Reproduction • Asexual: The production of offspring by a single parent. • Sexual: The production of offspring by a combination of genetic material from 2 parents.

  4. Asexual Reproduction • Binary fission: “Dividing in half” • 1 parent splits evenly into 2 daughter cells. • Budding: • Parent organism divides into 2 unequal parts. • Regeneration • The regrowth of body parts from pieces of an animal (Planaria)

  5. The cell cycle multiplies cells

  6. DNA • Chromosome: Structure that contains DNA during cell division. • Sister chromatids: Chromosome duplication. (2 copies of DNA) • Daughter Chromosomes: 2 identical copies of original chromosome

  7. Chromosomes • Centromere: The region where 2 chromatids are joined together

  8. Cell Cycle • Interphase: Cell doing regular cell things. • Mitosis: Genetic material and cell duplicates. • Cytokinesis: Cytoplasm divides and cell splits into 2 identical cells.

  9. S phase (DNA synthesis; chromosome duplication) • The cell cycle consists of two distinct phases Interphase (90% of time) G1 G2 Mitotic phase (M) (10% of time) • Interphase • Mitotic phase Mitosis Cytokinesis Figure 8.6

  10. Cells divide during the mitotic phase

  11. Mitosis and Cytokinesis Interphase • Mitosis • Is the division of the chromosomes • Is preceded by interphase Centrosomes (with centriole paris) Chromatin Nucleolus Nuclear envelope Plasma membrane

  12. Mitosis consists of four distinct phases Prophase Metaphase Anaphase Telophase & cytokinesis

  13. Early Prophase - Mitosis Begins Duplicated chromosomes begin to condense Figure 9.7 Page 156

  14. Late Prophase • New microtubules are assembled • One centriole pair is moved toward opposite pole of spindle • Nuclear envelope starts to break up

  15. Transition to Metaphase • Spindle forms • Spindle microtubules become attached to the two sister chromatids of each chromosome

  16. Metaphase • All chromosomes are lined up at the spindle equator • Chromosomes are maximally condensed

  17. Anaphase • Sister chromatids of each chromosome are pulled apart • Once separated, each chromatid is a chromosome

  18. Telophase • Chromosomes decondense • Two nuclear membranes form, one around each set of unduplicated chromosomes

  19. Results of Mitosis • Two daughter nuclei • Each with same chromosome number as parent cell • Chromosomes in unduplicated form

  20. Prophase Metaphase Fragments of nuclear envelope Early mitotic spindle Centrosome Centromere Chromosome, consisting of two sister chromatids Spindle microtubules Spindle

  21. Anaphase Telophase and Cytokinesis • Anaphase Nucleolus forming • Telophase Cleavage furrow Nuclear envelope forming Daughter chromosomes Figure 8.7.3

  22. Mitosis • Cytokinesis: • In animals cleavage furrow pinches the cell into 2 identical cells. • In plants the cell plate joins with existing cell wall to form a new cell wall between the 2 new cells.

  23. Cleavage furrow • Cytokinesis is different in plant and animal cells Cleavage furrow Contracting ring of microfilaments Daughter cells (a) Animal cell cytokinesis

  24. Wall of parent cell Cell plate forming Daughter nucleus Vesicles containing cell wall material New cell wall Cell plate Cell wall (b) Plant cell cytokinesis Daughter cells

  25. So How Do We Remember The Order of Mitosis? • Interphase • Prophase • Metaphase • Anaphase • Telophase • IPee More After Tea!

  26. Cancer cells grow and divide out of control

  27. Cancer Cells: Growing Out of Control • Normal plant and animal cells have a cell cycle control system • When the cell cycle control system malfunctions • Cells may reproduce at the wrong time or place • A benign tumor may form

  28. Cancer cells divide excessively • Cancer cells spread from a malignant tumor • Metastasis is the spread of cancer Lymph vessels Tumor Glandular tissue Metastasis A tumor grows from a single cancer cell. Cancer cells invade neighboring tissue. Cancer cells spread through lymph and blood vessels to other parts of the body

  29. Cancer Treatment • Cancer treatment • Radiation therapy disrupts cell division • Chemotherapy involves drugs that disrupt cell division

  30. Sexual Reproduction and Genetics Honors Biology Chapter 10

  31. Genetics • The science of heredity. • Inherited characteristics and patterns • Predictions of ratios for a trait in offspring. • How chromosomes effect inheritance.

  32. Meiosis functions in sexual reproduction

  33. Chromosome Lingo • Homalogous: 2 pair of matching chromosomes for the same characteristic. • Autosomes: Body cell chromosomes (22 pairs of autosomes in humans) • Sex chromosomes: X & Y genes in humans. ( 1 pair of sex chromosomes)

  34. Diploid / Haploid • Diploid cells: 2 homologous sets of chromosomes (2n). • Somate (body cells) • Diploid # for humans is 46 • Haploid cells: 1 set of chromosomes (1n). • Gametes (egg & sperm) • Haploid # for humans is 23

  35. Fertilization • Fertilization: The fusing of 2 haploid nuclei • Zygote: The resulting diploid cell from fertilization

  36. Meiosis • In meiosis • Haploid gametes are produced in diploid organisms • Two consecutive divisions occur, meiosis I and meiosis II, preceded by interphase • Crossing over occurs

  37. Meiosis I • Prophase I: • Synapsis: Homologous chromosomes, each has 2 sister chromatids, pair up forming a tetrad. • Each tetrad has 4 chromatids. • Crossing over can occur (exchanging of segments between chromosomes) • The rest of prophase I is similar to mitosis.

  38. Prophase I • Each duplicated chromosome pairs with homologue • Homologues swap segments • Each chromosome becomes attached to spindle

  39. Metaphase I • Chromosomes are pushed and pulled into the middle of cell • The spindle is fully formed

  40. Anaphase I • Homologous chromosomes segregate • The sister chromatids remain attached

  41. Telophase I • The chromosomes arrive at opposite poles • Usually followed by cytoplasmic division

  42. Meiosis I Meiosis I: Homologous chromosomes separate Telophase I and Cytokinesis Prophase I Metaphase I Anaphase I Sites of crossing over Microtubules attached to Chromosomes Sister chromatids remain attached Cleavage furrow Spindle Sister chromatids Tetrad Centromere Tetrads line up Homologous chromosomes pair and exchange segments Pairs of homologous chromosomes split up Two haploid cells form: chromosomes are still double

  43. Prophase II • Microtubules attach to the kinetochores of the duplicated chromosomes

  44. Metaphase II • Duplicated chromosomes line up at the spindle equator, midway between the poles

  45. Anaphase II • Sister chromatids separate to become independent chromosomes

  46. Telophase II • The chromosomes arrive at opposite ends of the cell • A nuclear envelope forms around each set of chromosomes • Four haploid cells

  47. Meiosis II Meiosis II: Sister chromatids separate Telophase II and Cytokinesis Prophase II Anaphase II Metaphase II Sister chromatids separate Haploid daughter cells forming During another round of cell division, the sister chromatids finally separate; four haploid daughter cells result, containing single chromosomes

More Related