Brooks Biological Principles Exam 3 Rated A+

Brooks Biological Principles Exam 3 Rated A+ Mitosis • the duplication and division of the nucleus • results in clones with *no* variation or adaptation • takes place in somatic cells (non-sex cells) • starts with one cell and creates 2 identical daughter cells • replicated chromosomes are evenly divided so that each daughter cell receives a complete set (46 chromosomes) • *can occur by itself*, but usually involves cytokinesis • not synonymous with cellular division • single-celled prokaryotes and single celled eukaryotes reproduce asexually, but eukaryotes are followed by cytokinesis Purpose of Mitosis 1. Growth: to increase the number of cells 2. Tissue repair/replacement 3. Asexual Reproduction Cell Division A process by which a parent cell duplicates its genetic material and then divides into two similar cells = Cytokinesis Cytokinesis • the duplication and divison of the *rest* of the cell, *excluding* the nucleus • occurs during telophase • can happen during mitosis, but generally doesn't have to occur with mitosis • will either develop into new cell walls (plants) or plasma membranes (animals) for each daughter cell Mitosis is not equal to Cell division/Cytokinesis Only duplicates the nucleus, not the entire cell In the cells of some organisms, mitosis occurs without cytokinesis. This will result in cells with more than one nucleus (plasmodium/slime mold) Ploidy number of the kinds of chromosomes found in a species denoted as "n" What is the ploidy for humans? diploid, 23 pairs of chromosomes, 46 chromosomes total What is the ploidy for bacteria? diploid, 46 chromosomes Haploid (n) 1 set of each kind of chromosome no homologous chromosomes *only in gametes* Diploid (2n) 2 sets of each kind of chromosome, one set inherited from each parent contains a pair of homologous chromosomes *in all other body cells* You should do a ploidy count when the mitotic or meiotic stages have been completed, and new nuclear membranes