VJC H2 Bio Chpt 08 Mitotic Cell Cycle Notes 2024.pdf

1 VICTORIA JUNIOR COLLEGE BIOLOGY DEPARTMENT YEAR ONE LECTURE 2024 (H2 9744 & H1 8876) CORE IDEA 2: GENETICS AND INHERITANCE Mitotic Cell Cycle Learning Outcomes: Candidates should be able to: (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 membrane and centrioles). (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 detail of the mechanism is not required.) Note: LO (f) – (g) in H1 syllabus Contents: Section Page Learning Outcome 1. The Mitotic Cell Cycle 2-9 LO (n) (f) in H1 8876 (a) Introduction to the cell cycle 2 (b) Organisation of genetic materials during cell cycle 3 (c) Centrosomes, centrioles, and spindle fibres 4 (d) Process of mitosis 6 (e) Process of cytokinesis 9 2. Importance of Mitosis and Regulation of the Mitotic Cell Cycle 10-12 LO (o) (g) in H1 8876 (a) Significance of Mitosis 10 (b) Cell cycle checkpoints 11 Need a song to get in beat with mitosis? (overview) https://www.youtube.com/watch?v=pOsAbTi9tHw https://www.youtube.com/watch?v=f7Dmhfo7XXA

2 1. THE MITOTIC CELL CYCLE Describe the events that occur during the mitotic cell cycle and the main stages of mitosis (including the behaviour of chromosomes, nuclear envelope, cell membrane and centrioles). (a) Introduction to the cell cycle • Recall t he Cell Theory states that the cell is a fundamental unit of structure, function and organisation in all living organisms and new cells are formed from other existing cells. • The cell cycle is an ordered sequence of events in cell division Fig. 1. Stages of the cell cycle. Source: https://openstax.org/books/biology/pages/10-2-the-cell-cycle 1. Mitosis is the last p art of the cell cycle. In fact, the mitotic (M) phase , which includes both mitosis and cytokinesis, is usually the shortest part of the cell cycle. 2. Mitotic cell division comes after a much longer stage called interphase, which often accounts for about 90% of the cycle. Interphase consists of three main stages: G1, S and G2 phases. (While G stands for gap, you can use G1 and G2 mnemonically as growth phases, when the cell synthesizes a variety of proteins; For e.g., in G1 the synthesised proteins are required for DNA replication and in G2, microtubule proteins are required during mitosis.) G1 phase • Cell synthesises organelles such as mitochondria and ribosomes. • Builds up a large store of energy. • Manufactures proteins such as histones, ribosomal proteins and tubulin (a subunit of spindle fibres). S phase • DNA replication/ Synthesis occurs. • A microtubule-organizing structure called the centrosome is also duplicated. G2 phase • Cell co