2022 HCI Cell and Nuclear Division Notes

HWA CHONG INSTITUTION / 2022-2023 H2 BIOLOGY / Core Idea 2 / Cell And Nuclear Division 1 Cell and Nuclear Division There are two different types of cell cycles: mitotic and meiotic. Cell cycles are tightly regulated at various checkpoints. The mitotic cell cycle is necessary for growth and repair while the meiotic cell cycle is necessary to generate gametes. Meiosis gives rise to genetic variation between gametes through crossing over of homologous chromosomes and the independent assortment of bivalents. Learning Outcomes Candidates should be able to: 2(n) describe the events that occur during the mitotic cell cycle and the main stages of mitosis (including the behaviour of chromosomes, nuclear envelope, cell surface membrane and centrioles). 2(o) explain the significance of the mitotic cell cycle (including growth, repair and asexual reproduction) and the need to regulate it tightly (knowledge that dysregulation of checkpoints of cell division can result in uncontrolled cell division and cancer is required, but details of the mechanism are not required) 2(s) describe the events that occur during the meiotic cell cycle and the main stages of meiosis (including the behaviour of chromosomes, nuclear envelope, cell surface membrane and centrioles) (names of the main stages are expected, but not the sub-divisions of prophase). 2(t) explain the significance of the meiotic cell cycle (including how meiosis and random fertilisation can lead to variation) Use the knowledge gained in this section in new situations or to solve related problems. Learning Experiences 2.5.4 Different Stages of Mitosis The behaviour of chromosomes at the different stages of mitosis can be observed through the preparation of microscopy slides of squash root tip cells. The laboratory procedures can be found on OPAL. 2.5.5 Different Stages of Meiosis The behavio ur of chromosomes at the different stages of meiosis can be observed through the preparation of microscopy slides of squashed anther cells.

HWA CHONG INSTITUTION / 2022-2023 H2 BIOLOGY / Core Idea 2 / Cell And Nuclear Division 2 Lecture Outline Page 1. Cell and Nuclear Division 5 1.1 Chromosome number 6 1.2 Ploidy Level 7 1.3 Human Life Cycle 8 2. Important terms and definitions 9 3. The Cell Cycle 13 3.1 Interphase 13 4. Nuclear Division – Mitosis 4.1 Stages of Mitosis 15 4.2 Significance of Stages in Mitosis 18 4.3 Cytoplasmic Division – Cytokinesis 19 4.4 Significance of Mitosis 21 5. Nuclear Division – Meiosis 5.1 Stages of Meiosis I 23 5.2 Cytokinesis I 27 5.3 Stages of Meiosis II 28 5.4 Cytokinesis II 30 5.5 Significance of Stages in Meiosis 32 5.6 Significance of Meiosis 33 6. Comparing Mitosis and Meiosis 35 Websi