The Cell Cycle and Cell Division

Continuation of the cell structure and function. This presentation highlights the cell cycle and concentrate on how cell division occur and the steps involved in cell dividing.
2018/2019

1. THE CELL CYCLE AND CELL DIVISION Presented by: Fasama Hilton Kollie Lecturer, Department of Biology Mother Patern College of Health Sciences

2. CHAPTER OUTLINE Cell Division Importance of Cell Division Prokaryotic and Eukaryotic Cell Division Cell Cycle Regulation of the Cell Cycle

3. LESSON OBJECTIVES By the end of this session, the learners will be able to ; Define cell division and cell cycle Identify the purpose of cell division Describe cell division in prokaryotic and Eukaryotic cell Describe the cell cycle

4. CELL DIVISION It’s the process by which a cell divides to form two new cells Three types of cell division or cell reproduction in organism Prokaryotes (bacteria) Binary fission Divides forming two new identical cells

5. Eukaryotes Mitosis Cell or organism growth Replacement or repair of damaged cells Meiosis formation of sex cells, or gametes

6. WHY DO CELLS DIVIDE? Cells divide for growth, development, repair of worn-out tissues and reproduction To facilitate the exchange of materials To control DNA overloading

7. PROKARYOTIC CELL DIVISION Binary Fission Three (3) major steps; DNA Replication DNA is copied resulting into two identical chromosomes Chromosome Segregation Chromosomes separate and move towards ends (poles) of cell Cytokinesis (Separation) Cytoplasm divides forming two (2) cells Each new daughter cell is Genetically Identical to parent cell

8. Prokaryotic Cell Division

9. EUKARYOTIC CELL DIVISION C ell division that results in two daughter cells each having the same number and kind of chromosomes as the parent cell MITOSIS Two (2) main steps: Mitosis Fours steps; [Prophase>Metaphase>Anaphase>Telophase] Cytokinesis Cytoplasm divides forming two new daughter cells Each daughter cell is Genetically Identical to parent cell

10. Eukaryotic Cell Division Cont. C ell division that results in four daughter cells MEIOSIS Two (2) major steps: Mitosis Fours steps; [Prophase>Metaphase>Anaphase>Telophase] Cytokinesis Cytoplasm divides forming two new daughter cells Each daughter cell is NOT Genetically Identical to parent cell

11. CELL CYCLE

12. THE CELL CYCLE The sequence of events from the time a cell first arises as a result of cell division until the time when that cell itself divides. Arise – Divide This consist of periods of; Growth and Development DNA Replication Preparation For Division Cell Division Cell after division begins a new cycle

13. The Cell Cycle Consist of two(2) main periods; Interphase Mitotic Phase M phase G 2 phase S phase G 1 phase

14. CELL CYCLE - Interphase Interphase: period of growth and DNA replication between cell divisions Three (3) phases: G 1 Phase Cell increases in size S Phase Replication of DNA Two sister strands of DNA called chromatids are produced G 2 Phase Organelles double New cytoplasm forms All other structures needed for mitosis form Centrioles Nuclear membrane Nucleolus Chromosomes

15. M phase G 2 phase S phase G 1 phase CELL CYCLE

16. CELL CYCLE – Mitotic Phase Mitotic phase is the stage when a cell divides Mitosis – the division of a single nucleus into two genetically identical daughter nuclei This division involves two(2) processes; Division of the nucleus Separation of the cytoplasm and the new nuclei into daughter cells

17. Mitotic Phase Divided into two (2) mitotic phases 1 st MP contain four stages (P-MAT ) Prophase, metaphase, anaphase and telophase 2 nd MP is cytokinesis

18. Prophase Metaphase Anaphase Telophase P-MAT Interphase 1 2 3 4 Cytokinesis Mitosis

19. Interphase: Centrioles Nuclear membrane Nucleolus Chromatids

20. Early Prophase: Chromatids condense becoming chromosomes Nucleolus disappears Centrioles separate and start moving to opposite ends of the cell Spindle begins to form Chromatids connected by a centromere . Centrioles Spindle made of microtubules

21. Late Prophase: The nuclear membrane fragments and the microtubules invade the nuclear area Centrioles have moved to the opposite poles The spindle is completely formed centrioles Microtubules form a complete spindle chromatids centrioles

22. Metaphase: In metaphase; The chromosomes are aligned at the metaphase plate Centrioles move at polar ends and projects spindle fibers to connect each chromosome Centriole s Chromosomes Spindle composed of microtubules

23. Anaphase: In anaphase; The paired chromosomes (sister chromatids) separate Separated chromatids move to opposite pole Partial division of cytoplasm begins Chromatids are being pulled to opposite sides of the cell . Shortening of the microtubules

24. Telophase: In telophase; Chromosomes are at the poles Chromosomes uncoil-turn chromatin Nuclear envelops reforms Spindle fiber disappear Nuclear membrane is returning

25. Cells return to interphase Cytokinesis: Occurs at the end of mitosis Animal cells: a cleavage furrow separates the daughter cells Plant cell : a cell plate separates the daughter cells Daughter cells are genetically identical

26. Mitosis Animation

27. Name the phases starting at the top. Mitosis SELF QUIZ Design an Education Game from Here A B C D E

28. Name the phases: Identify W Sister Chromatid 2 . Identify X Spindle fibre Identify Y Centriole Identify Z Centromere SELF QUIZ z w

29. Name this phase and provide brief description Telophase

30. CONTROL OF THE CELL CYCLE Regulatory proteins called cyclins control the cell cycle at checkpoints: G1 Checkpoint —decides whether or not cell will divide S Checkpoint —determines if DNA has been properly replicated Mitotic Spindle Checkpoint —ensures chromosomes are aligned at mitotic plate

31. REFERENCE Nabor , Murray W., INTRODUCTION TO BOTANY . Copyright 2004 Pearson Education, Inc., Publilshing as Benjamin Cummings, 1301 Sansome St., San Francisco, CA 94111. www.aw-bc.com CK – 12 https://www.ck12.org/biology/cell-division/lesson/Cell-Division-BIO/ Image Attributions [ Prokaryotic cell division ] Credit: Mariana Ruiz Villarreal ( LadyofHats ) for CK-12 Foundation Source: CK-12 Foundation License: CC BY-NC 3.0