St. Bridget School Quezon City General Biology 1 Mitosis PDF

ST. BRIDGET SCHOOL QUEZON CITY High School Department CELL CYCLE: MITOSIS GENERAL BIOLOGY 1 QUARTER 1 – LESSON 5 OBJECTIVES characterize the phases of the cell 01 cycle and their control points describe the stages of mitosis 02 given 2n = 6 03 explain the significa...

ST. BRIDGET SCHOOL QUEZON CITY High School Department CELL CYCLE: MITOSIS GENERAL BIOLOGY 1 QUARTER 1 – LESSON 5 OBJECTIVES characterize the phases of the cell 01 cycle and their control points describe the stages of mitosis 02 given 2n = 6 03 explain the significance of mitosis  CELL CYCLE Match the each illustration to its respective phase. A B C D E INTERPHASE PROPHASE METAPHASE ANAPHASE TELOPHASE  CELL CYCLE Match the each illustration to its respective phase. A B C D E INTERPHASE PROPHASE METAPHASE ANAPHASE TELOPHASE  REVIEW Sex Cells Body Cells or Gametes or Somatic Cells Includes the egg cells All the other cells in the and sperm cells body of an organism MEIOSIS MITOSIS haploid (n) diploid (2n)  REVIEW Sex Cells Body Cells or Gametes or Somatic Cells Includes the egg cells All the other cells in the and sperm cells body of an organism MEIOSIS MITOSIS haploid (n) diploid (2n)  REVIEW Sex Cells Body Cells or Gametes or Somatic Cells Includes the egg cells All the other cells in the and sperm cells body of an organism MEIOSIS MITOSIS haploid (n) diploid (2n)  REVIEW Sex Cells Body Cells or Gametes or Somatic Cells Includes the egg cells All the other cells in the and sperm cells body of an organism MEIOSIS MITOSIS haploid (n) diploid (2n)  REVIEW DNA PACKAGING Image retrieved from https://socratic.org/questions/what-are-chromatin-and-chromosomes-made-from  REVIEW DNA PACKAGING Image retrieved from https://socratic.org/questions/what-are-chromatin-and-chromosomes-made-from  REVIEW Parts of a Chromosome Sister chromatids two chromatids attached together by a single centromere REVIEW 1 chromosome 1 chromosome 1 chromatid 2 chromatids  2n = 6 diploid Chromosomes = 6 Chromosomes = 6 Chromosomes = 6 Chromatids = 12 before synthesis after synthesis after Mitosis  Human Chromosomes 46 Chromosomes or 23 Pairs Chromosomes = 46 Chromosomes = 46 Chromosomes = 46 Chromatids = 92 before synthesis after synthesis after Mitosis The number of chromosomes remains the same all-throughout mitosis 2n = 6 diploid n=3 haploid Mitosis (somatic cells) Meiosis (gametes) In theory = 6/6 In theory = 3/6 For Humans = 46/46 For Humans = 23/46  CELL CYCLE A series of events that takes place in a cell as it grows and divides.  Before a cell divides, it will prepare for division by resting, growing, and replicating its chromosomes. It will also be subjected to various checkpoints to maintain the accuracy of the process. This stage is called INTERPHASE  GAP 1 Phase INTERPHASE Growth and Development G1/S checkpoint S Phase DNA Synthesis GAP 2 Phase GAP 0 Phase Preparation for Mitosis (Resting Phase) G2/M checkpoint INTERPHASE 24-hr cell cycle Gap 1 = 11hr Synthesis = 8hr Gap 2 = 4hr Division / Mitosis = 1hr PHASES OF MITOSIS  PHASES OF MITOSIS PROPHASE Shortening and thickening of chromatin forming chromosomes. Disappearance of the nuclear membrane and nucleus Migration of centrioles to opposite poles  PHASES OF MITOSIS METAPHASE Chromosomes will line up in the middle of the cell Spindle fibers from the microtubules of centrioles will form and attach to each sister chromatid through the kinetochore  PHASES OF MITOSIS METAPHASE Spindle Assembly Checkpoint (SAC) When not correctly attached to the spindle, kinetochores activate the SAC network, which in turn blocks cell cycle progression.  PHASES OF MITOSIS ANAPHASE Sister chromatid begins to separate and move towards the poles. The cell poles start to move farther apart. By the end of the anaphase, the cell pole has a complete set of chromosomes.  PHASES OF MITOSIS TELOPHASE The polar fibers continue to lengthen until the nuclei begin to form. Nuclear envelopes for each nucleus begin to appear. The chromosomes uncoil and become chromatin fibers again. Cytokinesis - division of the cytoplasm PHASES OF MITOSIS TELOPHASE animal cells = cleavage furrows plant cells = cell plates CONTROL OF THE CELL CYCLE Regulation by external events Regulation by internal checkpoints Regulation by positive & negative molecule regulators Regulation by external events The initiation or inhibition of cell division can be triggered by events external to the cell. TRIGGERS: Death of nearby cells Release of hormones (HGH) Size of the cell Regulation by internal checkpoints Internal control mechanisms operate at different cell cycle stages to avoid mistakes and aberrations will not be passed on to daughter cells. Cell Cycle Checkpoints: G1 Checkpoint (G1/S) G2 Checkpoint (G2/M) M Checkpoint (SAC) Regulation by molecule regulators Intracellular molecules that regulate the cell cycle that may either promote progress to the next phase or halt the cycle. Positive Regulators Cyclins Cyclin-Dependent Kinases Different cyclins and CDKs bind at specific points in the cell cycle, thus regulating different checkpoints. Regulation by molecule regulators Intracellular molecules that regulate the cell cycle that may either promote progress to the next phase or halt the cycle. Regulation by molecule regulators Intracellular molecules that regulate the cell cycle that may either promote progress to the next phase or halt the cycle. Negative Regulators Retinoblastoma protein (Rb) p53 p21 All three of these were discovered to be damaged or nonfunctional in cancer cells. CANCER CELLS Nowell (1976) and Cairns (1975) CANCERS are generated by cell-level evolutionary processes TUMORS = overgrowth of cells = bearing genetic injuries = confer growth advantages over neighboring cells CHARACTERISTICS OF CANCER CELLS Clonality genetic and epigenetic changes occur over time in individual cancer cells Autonomy proliferate despite regulators and checkpoints Anaplasia biazzare-looking, large nuclei, metastasizing Angiogenesis formation of new system of blood vessels Retrieved from https://www.who.int/ activities/preventing- cancer