Mitosis Review SBI 3 U Mitosis The Cell

Mitosis Review SBI 3 U

Mitosis

The Cell Cycle • All phases except mitosis are considered part of Interphase

The Chromosome • During interphase, the chromosomes exist as chromatin (stringy mass) • Each chromosome is duplicated during interphase • The original chromosome is attached with a centromere to its sister chromatid

Stages of Mitosis • Prophase – Chromosomes become visible as they shorten and thicken – In animal cells, structures called centrioles move to opposite ends of the cell and provide attachment for spindle fibres – Nuclear membrane begins to disappear.

Stages of Mitosis cont. • Metaphase – Sister chromatids move toward the equatorial plate – Spindle fibres are attached to centromeres

Stages of Mitosis cont. • Anaphase – Centromeres divide and the chromatids, now daughter chromosomes, move to opposite poles

Stages of Mitosis cont. • Telophase – Chromosomes lengthen – Spindle fibres dissolve – Nuclear membrane forms around each set of chromatin – Followed by cytokinesis (division of cytoplasm)

Cytokinesis • In animal cells – Cleavage furrow develops, pinching off the cell into two • In plant cells – Cell plate forms into a new cell wall

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