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Get ready for the Chapter 6 Quiz on cell cycle and mitosis with this comprehensive review. Learn about the phases of mitosis, the control mechanisms of the cell cycle, and the causes and effects of mutations and cancer.
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Hand in W.S. 6.2 before the bell rings Review for Chapter 6 Quiz 1 Notes - mitosis “Nothing great was ever achieved without enthusiasm.” Ralph Waldo Emerson To begin learning about Chapter 6 Title: Biology 12/13/06 Class Topics Objectives: Saturday, January 4, 20207:36 PM
Finals Schedule12/15/06 - 12/21/06 • # Revised lunch schedule • Friday the bus leaves at 10:40 • Buses run at regular times – Mon, Tues, and Wed • Thursday the bus leaves at 11:00
Class Assignments What By When • W.S. 6.2 (DR/Quiz) 12/13/06 • Chapter 6 Quiz 1 12/13/06 • Read 128-132 12/13/06 • Due this class period • Due next class period • Due in the future
Grade Sheet 1A – SR p. 61 - 5 pts Measurement W.S. – 10 pts 3A SR p. 42 – 6 pts 4A – SR p. 47 – 5 pts 2A – Measurement W.S. – 10 pts SR p. 80 – 5 pts
Postquiz Activities • Read 128-132
Length of cell cycle • Ranges from 20 minutes to 20 hours • Some cells divide constantly and others never divide • Muscle cells • Red Blood cells • Skin cells • Bone cells • Nerve cells
Mutation(Handout) • Changes in chromosome structure • Deletion • Cri du chat syndrome • 5p deletion • Translocation • 14-21 • Another cause of Down Syndrome From: http://www.criduchat.asn.au/criduchat/what.htm#Diagram%201
Cell Cycle • G1 - growth and normal cell activity • G0 – never divides again • S - Synthesis of DNA • DNA replication, Copying DNA, forming chromatids • G2 - Growth for division, organelles double • Mitosis - Division of the nucleus • Cytokinesis - Division of the cytoplasm (cell) • Interphase (longest phase) • G1, S, G2, (G0 as well)
Controlling the cell cycle • “Checkpoints” • 1. Cell growth (G1) • to begin DNA synthesis • Entry point for G0 • 2. DNA synthesis (G2) • Checking for errors in DNA • 3. Mitosis • Exiting mitosis, beginning of G1 • A build up of proteins (cyclins) stimulate the move to next stage
Chapter 6 Quiz 1 Review • Matching • Centromere, chromatid, DNA, somatic cell, gamete • Multiple choice • Chromatin, diploid, gene, haploid, prokaryotic cell division • Short Answer • Human chromosome number, pairs of human chromosomes, sex chromosomes • Mutation • Deletion, translocation • Cell cycle labeling
Cancer • Uncontrolled cell growth • Cells stop responding to control mechanisms • Read p. 127
Exploring Further • What causes the damage to genes controlling the cell cycle? • Carcinogens • What do they do? • “Stepping on the Accelerator” • oncogenes • “Releasing the Brakes” • Tumor supressor genes
Mitosis • A process in which eukaryotic cells form two identical nuclei. • Each cell receives a complete set of chromosomes • Karyokinesis • division of the nucleus - actual process of mitosis - not in prokaryotes • Cytokinesis • division of the cytoplasm, true cell division • 2 exact replica independent cells • Different in plant and animals
Preparation for Mitosis • Formation of spindles • Microtubules and centrioles that move the chromosomes • Centrioles form ‘poles’ (only in animals) • Microtubules of spindle attach to centrioles and centromere of chromosomes
Mitosis • Prophase • Metaphase • Anaphase • Telophase
Prophase • 1st phase of mitosis (longest) - • chromosomes begin to coil up from chromatin • Centrioles appear • Not in plants • Organize microtubules and create spindle • Spindle fibers appear • clusters of microtubules
Metaphase • chromosomes move to the center of the cell • equator • metaphase plate • Shortest phase
Anaphase • Chromosomes separate at the centromere • Completed when movement stops
Telophase • Opposite of prophase • chromosomes uncoil into chromatin • Centrioles disappear (animals) • Spindle fibers disappear • Distinct nuclei are formed • Beginning of cytokinesis (usually)
Animal Cleavage furrow Dividing a balloon in two Plant Cell plate Dividing a room in two Cytokinesis - Forming Daughter Cells