What is Mitosis? Main form of reproduction for some organisms like the hydra (freshwater jellyfish). Process is called budding and is asexual reproduction Tissue renewal (healing) Cancer(abnormal mitosis) Growth and development

Fig Tumor A tumor grows from a single cancer cell. Glandular tissue Lymph vessel Blood vessel Metastatic tumor Cancer cell Cancer cells invade neigh- boring tissue. Cancer cells spread to other parts of the body. Cancer cells may survive and establish a new tumor in another part of the body Cancer occurs when the cell spends an abnormal amount of time dividing (mitosis)

Fig. 12-2c 20 µm (c) Tissue renewal

Fig. 13-2a (a) Hydra 0.5 mm Bud Parent

Fig. 12-6b PrometaphaseProphase G 2 of Interphase Nonkinetochore microtubules Fragments of nuclear envelope Aster Centromere Early mitotic spindle Chromatin (duplicated) Centrosomes (with centriole pairs) Nucleolus Nuclear envelope Plasma membrane Chromosome, consisting of two sister chromatids Kinetochore microtubule

Fig. 12-UN1 Telophase and Cytokinesis Anaphase Metaphase Prometaphase Prophase MITOTIC (M) PHASE Cytokinesis Mitosis S G1G1 G2G2

DNA – lots of it in a small space Chromatin – DNA found in this form in Interphase Chromosome DNA found in this form in mitosis

Fig. 12-UN3

Prophase Chromatin – coils and supercoils to form chromosomes Nucleoli disappear Nuclear membrane disappear Spindle begins to form as microtubules grow out of centrosomes (centrioles) Microtubules from spindle attach to kinetochores on chromosomes

Fig. 12-6d MetaphaseAnaphase Telophase and Cytokinesis Cleavage furrow Nucleolus forming Metaphase plate Centrosome at one spindle pole Spindle Daughter chromosomes Nuclear envelope forming

Metaphase Spindle fully formed Centrioles (animal cells) at opposite end of cell Chromosomes now on metaphase plate (middle of cell)

Anaphase 2 centromeres of each chromosome come apart separating sister chromosomes Free chromatid now called a chromosome Spindle fibers attached to chromosomes kinetochores contract while those not attached lengthen. Poles move further apart and cell elongates

Telophase Cell continues to elongate Nuclear membrane reforms Nucleolus forms Mitotic spindle disappears Cytokinesis occurs 2 genetically identical daughter cells form

Cytokinesis Division of the cytoplasm Occurs along with telophase Animal cells form a cleavage furrow which pinches the cell into 2 Plant cells form a cell plate

Cleavage furrow Fig. 12-9a 100 µm Daughter cells (a) Cleavage of an animal cell (SEM) Contractile ring of microfilaments Animal cytokinesis

Fig. 12-9b Daughter cells (b) Cell plate formation in a plant cell (TEM) Vesicles forming cell plate Wall of parent cell New cell wallCell plate 1 µm Plant cytokinesis

Fig Cleavage furrow 100 µm Contractile ring of microfilaments Daughter cells (a) Cleavage of an animal cell (SEM)(b) Cell plate formation in a plant cell (TEM) Vesicles forming cell plate Wall of parent cell Cell plate Daughter cells New cell wall 1 µm

Fig. 12-UN5 Mitosis video