The Cell Cycle (Module 2 Lesson 1)

Module 1: How Cells Reproduce THE CELL CYCLE Prepared by: Ms. Kate Justine R. Pinto OBJECTIVES: At the end of this module, the learners will be able to: 1.Describe the main events in the eukaryotic cell cycle; 2.Explain the phases and processes of the cell cycle.  LIF...

Module 1: How Cells Reproduce THE CELL CYCLE Prepared by: Ms. Kate Justine R. Pinto OBJECTIVES: At the end of this module, the learners will be able to: 1.Describe the main events in the eukaryotic cell cycle; 2.Explain the phases and processes of the cell cycle.  LIFE CYCLE  A sequence of recognizable stages that occur during an organism’s lifetime, from the first cell of the new individual until its death. DEFINITION OF TERMS a. Chromatin  Uncoiled DNA  Complex of DNA and protein that make up the chromosome. b. Chromatid  One of the two identical strands of DNA and protein that forms a replicated chromosome. c. Chromosome  Two (2) chromatids together, made of chromatid threads that becomes highly coiled and condensed during cell division. d. Telomere  Chromosome tips  P arm: short arm  Q arm: long arm  e. Centromere  Structure that holds together the two (2) chromatids.  f. Kinetochore A protein structure that forms at the centromere of every chromosome.  It binds microtubules of the spindle so that during Metaphase, the chromosomes would be able to properly align at the  OBSERVE! What can you say about the picture?  CELL DIVISION  CELL DISIVION  “Cellular Reproduction”  A process where new cells are reproduced from old ones, enabling all organisms to grow and reproduce. TWO (2) PROCESSES OF CELL DIVISION CELL CYCLE  CELL CYCLE A series of recognizable intervals and events in a cell's life.  During the entire lifespan of a particular cell, it will undergo repeated steps of cellular growth, development, and TWO (2) MAIN STAGES OF THE CELL CYCLE TWO (2) MAIN STAGES 1. Interphase 2. M Phase INTERPHASE 1. INTERPHASE The nondividing stage. The longest stage of a cell's life (around 90% of the entire cell cycle) Produces all materials required for growth. Preparation for division. 1. INTERPHASE MAJOR EVENTS: a. G1 Phase b. S Phase c. G2 Phase G1 PHASE a. G1 PHASE  "Gap 1 Phase" ; "Growth 1 Phase"  The longest phase in most cells.  The period when the cell increases in size in preparation for cell division. a. G1 PHASE (cont.) EVENTS:  The cell is still young, and it undergoes rapid growth.  Organelles are formed.  Proteins are produced.  Cells that are NOT dividing (muscle and nerve cells) remain at this stage throughout their life cycle. G1 CHECKPOINT THE RESTRICTION POINT  Ensures that the cell is large enough to divide and that enough nutrients are available to support the resulting daughter cells. G0 CHECKPOINT  "Resting Phase"  Used to describe cells in a resting state and are NOT dividing.  Cells are NOT able to move to the S phase and thus are unable to replicate their DNA. S PHASE b. S PHASE  “Synthesis Phase"  Replication: The genetic material (DNA) and chromosomes are duplicated.  At the end of this stage, each chromosome is made up of two sister chromatids attached at the centromere. G2 PHASE c. G2 PHASE  "Gap 2 Phase" ; "Growth 2 Phase"  Growth and preparation for cell division.  Assembly of proteins, such as microtubules, hollow protein fibers that cause the chromosomes to move during G2 CHECKPOINT  Makes sure that the DNA is correct.  Ensures that DNA replication in the S Phase has been successfully completed. M PHASE 2. M PHASE  "Mitosis or Meiosis Phase"  The cell undergoes cell division.  Division of the nucleus is called karyokinesis, while division of the cytoplasm is called cytokinesis. KARYOKINESIS  Nuclear division  Two (2) Types: a.Mitosis b.Meiosis KARYOKINESIS (cont.)  Whether nuclear division is by mitosis or meiosis, the process involves four stages, namely: a. Prophase b. Metaphase c. Anaphase CYTOKINESIS  Cytoplasmic division  Plant Cells: Involves the formation of a cell plate that eventually develops into the cell wall and the middle lamella.  Animal Cells: Occurs with the formation of a cleavage furrow.  In both plant and animal cells, cytokinesis produces daughter SEATWORK SEATWORK NO.1 F DIRECTIONS: On a ½ sheet of yellow paper, label the parts of E the cell cycle diagram then describe what is happening for each letter. How does the cell cycle contribute to the growth and renewal of living organisms? TO SUM IT UP!