Sc8 U2.1-2: Mitosis/Meiosis Unit 2 lesson 1: Mitosis ROLE OF DNA IN REPRODUCTION FOUND IN EUKARYOTES’ NUCLEUS CHROMATIN: NEARLY INVISIBLE THREAD-LIKE DNA – PROTEIN STRUCTURES IN NUCLEUS CHROMOSOMES: EASILY VISIBLE, COMPACTED CHROMATIN FORMED DURING MITOSIS CHROMATID: DUPLICATED CHROMOSOMES FORMED DURING MITOSIS CENTROMERES: STRUCTURE CONNECTING TWO DUPLICATED CHROMOSOMES AT CENTER

CELL CYCLE: THE 3 STAGE LIFE CYCLE OF AN EUKARYOTE CELL INTERPHASE: PERIOD THE CELL IS NOT DIVIDING THE LONGEST STAGE OF CELL CYCLE, CELL GROW TWICE ITS BEGINNING SIZE PRODUCES ORGANELLES, PERFORMS LIFE ACTIVITIES ENDS WITH THE DUPLICATION OF DNA MITOSIS: 4 PART PROCESS THAT EXACTLY DUPLICATES CELL’S NUCLEUS CYTOKINESIS: DIVISION OF THE CELL’S CYTOPLASM TAKES PLACE

MITOSIS: 4 PART PROCESS THAT EXACTLY DUPLICATES CELL’S NUCLEUS 1. PROPHASE: DOUBLED CHROMATIN CONDENSE INTO CHROMOSOMES CHROMOSOMES MADE OF 2 CHROMATID HELD TOGETHER BY CENTROMERE NUCLEAR MEMBRANE DISSOLVES 2. METAPHASE: RELEASED CHROMOSOMES LINE UP IN CELL CENTER CENTRIOLES FORM THIN SPINDLE FIBERS SPINDLE FIBERS ATTACH TO CENTROMERES 3. ANAPHASE: SPINDLE FIBERS SEPARATE, PULL CHROMOSOMES TO OPPOSITE SIDES 4. TELOPHASE: 2 NEW NUCLEAR MEMBRANES FORM AROUND CHROMOSOMES  

CYTOKINESIS: DIVISION OF THE CELL’S CYTOPLASM TAKES PLACE NEW CELL MEMBRANE DIVIDES CYTOPLASM CHROMOSOMES UN-COMPACT IN TO CHROMATIN 2 NEW, IDENTICAL DAUGHTER CELLS FORMED  

Unit 2 lesson 2: Meiosis CHROMOSOMES: USUALLY FOUND IN HOMOLOGOUS (IDENTICAL) PAIRS DIPLOID: ONE PAIR OF CHROMOSOMES HUMANS HAVE 23 PAIRS (46 CHROMOSOMES): ONLY ONE PAIR NOT HOMOLOGOUS HUMAN SEX CHROMOSOME CONTROL GENDER AND SECONDARY SEXUAL CHARACTERISTICS XX SEX CHROMOSOME RESULTS IN FEMALE XY SEX CHROMOSOME RESULTS IN MALE HALF OF EACH PAIR COMES FROM ONE PARENT’S GAMETE GAMETES: HAPLOID MALE (SPERM) OR FEMALE (EGG) SEX CELLS HAPLOID CELLS: CONTAIN ONLY ½ OF THE NEEDED CHROMOSOMES

MEIOSIS: CELL DIVISION THAT PRODUCES HAPLOID SEX CELLS PROCESS RANDOMLY MIXES GENES (DNA CHAINS RESPONSIBLE FOR CHARACTERISTICS) RESEMBLES MITOSIS DONE TWICE, PRODUCES 4 HAPLOID SEX CELLS WITH MIXED TRAITS 2 STAGE PROCESS MEIOSIS 1: RESEMBLES MITOSIS, SOME GENES CROSS, MIX CHROMATIDS REMAINED JOINED BY CENTROMERES NEW NUCLEAR, CELL MEMBRANES FORM – CELL FORMED NOT IDENTICAL MEIOSIS II: NO NEW DUPLICATION, MITOSIS-LIKE PROCESS WITHOUT DNA REPLICATION, RESULTING CELLS HAVE HALF-SET OF CHROMOSOMES 4 HAPLOID SEX CELLS RESULT

DOWN’S SYNDROME: GENETIC DISEASE CAUSED BY SEX CHROMOSOMES INSTEAD OF A PAIR MAY CAUSE HEALTH ISSUES AND LEARNING DISABILITIES MORE FREQUENT IN FEMALES