Why do cells divide? Genetically Programmed Cell volume gets too big External Stimulus Dividing bacteria

Cell division = One cell makes two cells Parent cell DNA replicates Two daughter cells are genetically identical to each other and to parent cell = clones

Chromatin = uncondensed DNA Chromosome = condensed DNA The same DNA can appear in two forms

1 Chromosome 1 chromatid per chromosome 1 DNA double helix 1 Chromosome 2 chromatids per chromosome 2 DNA double helices DNA replication

Cell division in eukaryotic cells: Karyokinesis = division of the nucleus Cytokinesis = division of the cytoplasm

Interphase 1.DNA called chromatin 2.DNA replicates 3.Cell does normal activities 4.Not a phase of mitosis

DNA = Chromatin Interphase nucleus

Interphase Chromatin in nucleus

Mitosis 1.Prophase 2.Metaphase 3.Anaphase 4.Telophase Know this page

Prophase Nuclear membrane disappears Nucleolus disappears Chromatin condenses into chromosomes Spindle fibers appear

Chromatin Chromosomes

Metaphase Chromosomes line up in center of cell

Chromatids (DNA double helix) Two chromatids per chromosome Centromere = holds chromatids together

Anaphase = Sister chromatids separate from each other

Telophase Cytokinesis makes 2 new cells Chromosomes decondense into chromatin Nucleolus reappears Nuclear membrane reappears

Early Telophase Late Telophase

Animal cell membranes pinches together between two new cells Plant cell wall grows between two new cells Cytokinesis

Plant Cytokinesis = division of cytoplasm Interphase Telophase Anaphase Metaphase Telophase Prophase

Interphase Animal cytokinesis = pinching of plasma membrane Late Telophase Early telophase Anaphase ProphaseMetaphase

65&w=366&prev=/images%3Fq%3Dmitosis%26start%3D20%26svnum%3D10%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26sa%3DN Plant or Animal cell mitosis? Plant

Telomeres = break off and lead to cell death and aging. Telomeres Telomerase Enzyme prevents loss of telomeres Found in 95% of Cancer cells Makes cells immortal Cancer drug = telomerase inhibitor