MITOSIS & CYTOKINESIS *centrioles – cylindrical shaped structures that make the spindle fibers *spindle fibers – cell structures that are made of microtubules and are involved in moving the chromosomes during cell division *Animal cells have 1 pair of centrioles. *Plant cells do not have centrioles, but they form a spindle that is almost identical to that of an animal cell.

Interphase: The cell is engaged in metabolic activity and preparing itself for mitosis. Chromosomes are not clearly visible. The DNA is copied during the Synthesis phase.

MITOSIS: Prophase: Chromosomes coil up and become visible centromere chromatid MITOSIS: Prophase: Chromosomes coil up and become visible during prophase. The nuclear envelope dissolves and spindles form.

Metaphase: During metaphase the chromosomes move to the center of the cell and line up along the equator. Spindle fibers link the chromatids of each chromosome to opposite poles.

Anaphase: Centromeres divide during anaphase. The two chromatids (now called chromosomes) move toward opposite poles as the spindle fibers attached to them shorten.

Telophase: A nuclear envelope forms around the chromosomes at each pole. Chromosomes, now at opposite poles, uncoil and the spindles dissolves. The spindle fibers break down and disappear. Mitosis is complete.

CYTOKINESIS: As mitosis ends, cytokinesis begins. *In animal cells, the cytoplasm of the cell is divided in half, and the cell membrane grows to enclose each cell, forming two separate cells. The cell is pinched in half by a belt of protein threads.

*In plant cells vesicles formed by the Golgi apparatus fuse at the midline of the dividing cell and form a cell plate. A cell plate is a membrane-bound cell wall that forms cross the middle of the plant cell. A new cell wall then forms on both sides of the cell plate. When complete, the cell plate separates the plant cell into two new plant cells

Animal vs. Plant Cell Belt of Proteins Cell Plate

Mitosis & Cytokinesis Plant Cell Animal Cell Inter Pro Telo Inter Pro Meta Ana Telo Ana Meta Animal Cell

Comparing Mitosis in Animal & Plant Cell

Mitosis in Onion Root Tips Interphase Early Prophase Late Prophase Metaphase Early Anaphase Late Anaphase Telophase Cytokinesis

Diploid: 2 sets of chromosomes (2n)