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
o CHROMATIDS REMAINED JOINED BY CENTROMERES
o NEW NUCLEAR, CELL MEMBRANES FORM – CELL FORMED NOT IDENTICAL
• MEIOSIS II: NO NEW DUPLICATION, MITOSIS-LIKE PROCESS
o WITHOUT DNA REPLICATION, RESULTING CELLS HAVE HALF-SET OF CHROMOSOMES
o 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