Transcript Mitosis ppt
CHAPTER 10 THE CELL CYCLE CELL GROWTH • A LIVING THING GROWS BECAUSE IT PRODUCES MORE AND MORE CELLS • SURFACE AREA OF A CELL DETERMINES HOW LARGE IT CAN GROW – SA is critical for passage of food, oxygen, and water entering and leaving the cell – As VOLUME increases, SURFACE AREA decreases To solve the problem of getting too large, the cell DIVIDES CONTROLS ON CELL GROWTH • DEPENDS ON FUNCTION – Muscle and nerve cells don’t divide – Skin, digestive, and bone marrow divide rapidly to replace those that wear out or • DEPENDS ON FOOD, CROWDING, & CONDITIONS IN SURROUNDING AREA • IF INJURY OCCURS (CELLS WILL GROW RAPIDLY AT THE SITE) • CONSEQUENCES OF UNCONTROLLED CELL GROWTH ARE SEVERE • CANCER CELLS HAVE LOST THEIR FUNCTION and the ABILITY TO CONTROL THEIR GROWTH RATE Life Span • Like all organisms, human cells have a given life span from birth to death. • Cells with long life spans don’t divide. • Cells with short life spans do divide. • Depends on the function of the cell. DEFINITIONS • CELL DIVISION - THE PROCESS WHEREBY THE CELL DIVIDES INTO 2 DAUGHTER CELLS • MITOSIS - PROCESS BY WHICH THE NUCLEUS OF A CELL IS DIVIDED INTO 2 NUCLEI; OCCURS IN SOMATIC (BODY) CELLS • CHROMOSOMES STRUCTURES IN THE CELL THAT CONTAIN THE GENETIC INFORMATION THAT IS PASSED ON FROM ONE GENERATION OF CELLS TO THE NEXT • CHROMATIN - DNA & PROTEIN; TIGHTLY PACKED; APPEARS GRANULAR; VISIBLE DURING INTERPHASE CHROMOSOMES • THE CELLS OF EVERY ORGANISM CONTAIN A SPECIFIC NUMBER OF CHROMOSOMES • HUMANS HAVE 23 PAIRS OR 46 CHROMOSOMES THE CELL CYCLE • INTERPHASE --> MADE UP OF 3 PARTS • MITOSIS --> MADE UP OF 4 PARTS • CYTOKINESIS --> MADE UP OF 1 PART Nuclear Division Growth to prepare for mitosis Cell Growth DNA replication D. Mitosis C. Growth (G2) A. Growth (G1) B. DNA Synthesis INTERPHASE Interphase INTERPHASE • A. G1 CELLULAR GROWTH AND DEVELOPMENT TAKES PLACE INTERPHASE • B. DNA SYNTHESIS (S) DNA IS REPLICATED INTERPHASE • C. GAP 2 (G2) SYNTHESIS OF ORGANELLES (SHORTEST PART OF INTERPHASE) MITOSIS • The process where one large cell becomes two identical smaller cells • Organisms do this for growth, repair, or Asexual Reproduction PHASES OF MITOSIS • PROPHASE – CENTRIOLE S SEPARATE FROM EACH OTHER AND MOVE TO THE POLES PROPHASE • NUCLEAR ENVELOPE BREAKS DOWN AND NUCLEOLUS DISAPPEARS PROPHASE (early) • CHROMATIN COILS UP AND BECOMES VISIBLE AS CHROMOSOMES Early Prophase PROPHASE (late) • CHROMOSOMES BECOME ATTACHED TO THE SPINDLE FIBERS AT THE CENTROMERE • SPINDLE FIBERS – FANLIKE MICROTUBULE STRUCTURE THAT SEPARATES THE CHROMOSOMES Late Prophase SPINDLE FIBERS CENTROMERE CENTRIOLE S CHROMOSOMES Prophase METAPHASE • CHROMOSOMES LINE UP ACROSS THE EQUATOR (CENTER) OF THE CELL Metaphase Metaphase Metaphase ANAPHASE • CENTROMERES SPLIT CAUSING THE SISTER CHROMATIDS TO SEPARATE, BECOMING INDIVIDUAL CHROMOSOMES – CONTINUE TO MOVE IN 2 GROUPS NEAR THE POLES Anaphase Anaphase Anaphase Anaphase TELOPHASE • CHROMOSOMES UNCOIL INTO TANGLE OF CHROMATIN Telophase Telophase Telophase TELOPHASE • NUCLEAR ENVELOPE REFORMS AROUND CHROMATIN – NUCLEOLUS BECOMES VISIBLE AGAIN CYTOKINESIS • DIVISION OF THE CYTOPLASM INTO THE 2 DAUGHTER CELLS CYTOKINESIS • Last part of the cell cycle • Cytoplasm divides into 2 daughter cells • In animals, the membrane folds in to form the cleavage furrow • Plants - Cell plate forms Cleavage Furrow Two Identical Daughter Cells • • • • • • SHORTCUT TO REMEMBER THE CELL CYCLE I nterphase P rophase M etaphase A naphase T elophase C ytokinesis • • • • • • I Played Marbles At Taco Cabana SHORTCUT TO REMEMBER MITOSIS • Pass Me A Taco: –Prophase –Metaphase –Anaphase –Telophase Animation of Mitosis • http://www.sci.sdsu.edu/multimedia/mitosi s/mitosis_gif1.html • http://www.loci.wisc.edu/outreach/bioclips/ CDBio.html