Transcript Mitosis3
CELL CYCLE AND MITOSIS Prokaryotic Cells Eukaryotic Cells CELL CYCLE VOCABULARY DNA (Chromosome) - DNA + proteins; contains genetic information about the organism’s traits. Gene - part of DNA strand with genetic ONE trait. information fo IN MITOSIS WE ARE VIEWING Autosomal chromosomes contain information that does not depend on your gender (sex). Ex: hair, eye color, weight, shape of ears BASIC STRUCTURES DNA Histones Chromatinunwouned form of DNA Chromosome BASIC STRUCTURES Chromosome- organized group of DNA Centromere- area on the chromosome where sister chromatids & spindle fibers attach. Telomere CHROMOSOME RELATIONSHIPS - - Sister Chromatids (single stranded chromosome) two identical pieces of DNA joined at the centromere made during replication. Each half of the X is a sister chromatid HOMOLOGOUS CHROMOSOMES Homologous chromosomes are pairs of unattached chromosomes with the same genes in the same place. Humans have 23 pairs! One from MOM and from DAD! one ORGANELLES USED IN THE CELL CYCLE Spindle fibers attach the centriole to the centromere; pull chromatid during cell division. Centriole forms and anchors the spindle fibers. THE CELL CYCLE Each time a cell goes through one complete cycle it becomes two cells 3 stages of the Cell Cycle Interphase Mitosis Cytokinesis EUKARYOTIC CELLS Complex Cells Have many chromosomes Example: plant, animal (human) Human chromosomes are organized in 23 homologous pairs Pairs have the same genes and same size Reproduce by: Mitosis 3 Stages (Pre-Mitosis, Mitosis, Post-Mitosis) 6 Steps PRE-MITOSIS STAGE 1: INTERPHASE Time where the cell is growing and replicates its DNA A majority of the cells life is spent in this phase All three phases make-up Interphase Interphase INTERPHASE Non-reproducing stage in which a cell spends most of it’s life Begins when cell reproduction ends Eukaryotic cells have strands of DNA (chromatin) Chromosomes replicate in preparation for mitosis STAGE 2: MITOSIS The second stage of a cell cycle The cells nucleus and nuclear material divide. 4 phases of Mitosis Prophase Anaphase Metaphase Telophase MITOSIS STEP 2: PROPHASE Centrioles move to opposite poles Chromosomes condense and become visible Nuclear membrane starts to disappear Spindle Fibers form and move to centromere Prophase (pro=first) MITOSIS STEP 3: METAPHASE Chromosomes line up at the equator Nuclear membrane is completely gone Spindle fibers reach out from the centrioles Spindle fibers attach to centromeres of the chromosome pairs MITOSIS STEP 4: ANAPHASE Centromeres break in half Half of each pair (1 line) are called single stranded chromosome Spindle fibers shorten Single stranded chromosome are being pulled to opposite poles MITOSIS STEP 5: TELOPHASE Chromosomes arrive at the pole Nuclear membrane forms around each mass of chromosomes Chromosomes unwind Two new daughter cells are formed POST-MITOSIS STEP 6: CYTOKINESIS Division of the cytoplasm Animal cells divide from the outside in (pinchin) Plants cells divide from the inside out There is a cell plate that forms in the middle, grows and connects to the cell wall. MITOSIS CONTROL OF CELL DIVISION Depends on type of cell Some cells never reproduce (mature nerve & muscle cells) Cancer – uncontrolled cell division One theory is that cell division may be stopped by cell-to-cell contact Cyclins – chemicals that control the cell cycle; this may be what is altered in cancerous cells