220 likes | 317 Views
Cell dIVISION. Mitosis and Meiosis Asexual v. Sexual Reproduction. Cell Division. “process where 1 cell splits into 2” Replaces somatic (body) cells in multicellular organisms Allows for multicelullar growth Allows for asexual reproduction in plants.
E N D
Cell dIVISION Mitosis and Meiosis Asexual v. Sexual Reproduction
Cell Division • “process where 1 cell splits into 2” • Replaces somatic (body) cells in multicellular organisms • Allows for multicelullar growth • Allows for asexual reproduction in plants
Chromosome –rod shaped structure made up DNA and protein a. held together by centromere - holds chromatids together until they separate during division b. only found during cell division
Chromosome Number • Human/animal chromosomes – sex chromosomes and autosomes • Humans have 46 chromosomesin somatic cells • Karyotype– used to examine an individual’s chromosomes
Haploid/Diploid Problems • Haploid Diploid = sex cell body cell ( x by 2) • Diploid Haploid = body cell sex cell ( ÷ by 2) • Diploid Diploid = body cell body cell Haploid Haploid = sex cell sex cell
Practice Problems • Dogs have 42 chromosomes in their diploid cells. How many are in their haploid cells? • If there are 23 chromosomes in a sperm cell, how many would be in the skin cell? • If there are 46 chromosomes in a nerve cell, how many would be in a blood cell? • If there are 23 chromosomes in a sperm cell, how many would be in a human ovum (egg)
Cell Division in Prokaryotes • Binary Fision – two identical cells are produced from one cell * division in bacteria
Cell Cycle • “series of events leading to cell division”
Mitosis • Asexual Reproduction • Diploid cells split into 2 identical diploid cells • Allows body cells to be replaced and cells to GROW
Phases of Mitosis 1. Prophase
Meiosis • “sexual reproduction” • Fusing of 2 haploid gametes to form 1 diploid zygote
Stages • 2 divisions a. Meiosis I
Sources of Genetic Variation • Crossing – over • Fertilization • Independent Assortment