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

Cancer occurs when the cell spends Fig. 12-20 Cancer occurs when the cell spends an abnormal amount of time dividing (mitosis) Lymph vessel Tumor Blood vessel Cancer cell Glandular tissue Metastatic tumor 1 A tumor grows from a single cancer cell. 2 Cancer cells invade neigh- boring tissue. 3 Cancer cells spread to other parts of the body. 4 Cancer cells may survive and establish a new tumor in another part of the body.

Fig. 12-2c 20 µm (c) Tissue renewal

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

(asexual reproduction) Bacteria Binary fission (asexual reproduction) No mitosis

Chromosome, consisting of two sister chromatids Fig. 12-6b G2 of Interphase Prophase Prometaphase Centrosomes (with centriole pairs) Chromatin (duplicated) Early mitotic spindle Aster Centromere Fragments of nuclear envelope Nonkinetochore microtubules Nucleolus Nuclear envelope Plasma membrane Chromosome, consisting of two sister chromatids Kinetochore Kinetochore microtubule

G1 S Cytokinesis Mitosis G2 MITOTIC (M) PHASE Prophase Telophase and Fig. 12-UN1 INTERPHASE G1 S Cytokinesis Mitosis G2 MITOTIC (M) PHASE Prophase Telophase and Cytokinesis Prometaphase Anaphase Metaphase

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

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

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

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

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

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

cytokinesis Fig. 12-9 Vesicles forming cell plate Wall of parent cell Cleavage furrow Cell plate New cell wall Contractile ring of microfilaments Daughter cells Daughter cells (a) Cleavage of an animal cell (SEM) (b) Cell plate formation in a plant cell (TEM)

Fig. 12-UN5 Mitosis video