Slide 1 of 38 Copyright Pearson Prentice Hall Prentice Hall Biology

10-2 Cell Division Slide 2 of 38 Copyright Pearson Prentice Hall In eukaryotes, cell division occurs in two major stages. The first stage, division of the cell nucleus, is called mitosis. The second stage, division of the cell cytoplasm, is called cytokinesis.

10-2 Cell Division Slide 3 of 38 Copyright Pearson Prentice Hall Chromosomes Genetic information is passed from one generation to the next on chromosomes. Before cell division, each chromosome is duplicated, or copied.

Slide 4 of 38 Copyright Pearson Prentice Hall 10-2 Cell Division

Slide 5 of 38 Copyright Pearson Prentice Hall Chromosomes Each chromosome consists of two identical “sister” chromatids. Each pair of chromatids is attached at an area called the centromere. Sister chromatids Centromere

10-2 Cell Division Slide 6 of 38 Copyright Pearson Prentice Hall Chromosomes When the cell divides, the chromatids separate. Each new cell gets one chromatid.

10-2 Cell Division Slide 7 of 38 Copyright Pearson Prentice Hall The Cell Cycle The cell cycle is the series of events that cells go through as they grow and divide. Interphase is the period of growth that occurs between cell divisions.

10-2 Cell Division Slide 8 of 38 Copyright Pearson Prentice Hall The Cell Cycle During the cell cycle: a cell grows prepares for division divides to form two daughter cells, each of which begins the cycle again

10-2 Cell Division Slide 9 of 38 Copyright Pearson Prentice Hall The Cell Cycle The cell cycle consists of four phases: G 1 (First Gap Phase) S Phase G 2 (Second Gap Phase) M Phase

10-2 Cell Division Slide 10 of 38 Copyright Pearson Prentice Hall Events of the Cell Cycle During the S phase, chromosomes are replicated DNA synthesis takes place Once a cell enters the S phase, it usually completes the rest of the cell cycle.

10-2 Cell Division Slide 11 of 38 Copyright Pearson Prentice Hall Events of the Cell Cycle The G 2 Phase (Second Gap Phase) organelles and molecules required for cell division are produced

10-2 Cell Division Slide 12 of 38 Copyright Pearson Prentice Hall Events of the Cell Cycle During G 1, the cell increases in size synthesizes new proteins and organelles

10-2 Cell Division Slide 13 of 38 Copyright Pearson Prentice Hall Cell Cycle Events of the Cell Cycle

10-2 Cell Division Slide 14 of 38 Copyright Pearson Prentice Hall Mitosis Biologists divide the events of mitosis into four phases: Prophase Metaphase Anaphase Telophase

10-2 Cell Division Slide 15 of 38 Copyright Pearson Prentice Hall Mitosis

10-2 Cell Division Slide 16 of 38 Copyright Pearson Prentice Hall Section 10-2 Prophase Spindle forming Chromosomes (paired chromatids) Centromere Click to Continue Mitosis Prophase

10-2 Cell Division Slide 17 of 38 Copyright Pearson Prentice Hall Mitosis Prophase first and longest phase. The centrioles are formed. Spindle forming Centromere Chromosomes (paired chromatids)

10-2 Cell Division Slide 18 of 38 Copyright Pearson Prentice Hall Mitosis A spindle forms, strands of proteins that helps separate the chromosomes. Spindle forming Centromere Chromosomes (paired chromatids)

10-2 Cell Division Slide 19 of 38 Copyright Pearson Prentice Hall Centriole Spindle Mitosis Click to Continue Metaphase

10-2 Cell Division Slide 20 of 38 Copyright Pearson Prentice Hall Mitosis Metaphase chromosomes line up across the center of the cell. spindle connects to the centromere Centriole Spindle

10-2 Cell Division Slide 21 of 38 Copyright Pearson Prentice Hall Individual chromosomes Anaphase Mitosis Anaphase

10-2 Cell Division Slide 22 of 38 Copyright Pearson Prentice Hall Mitosis Anaphase The sister chromatids separate into individual chromosomes. Individual chromosomes

10-2 Cell Division Slide 23 of 38 Copyright Pearson Prentice Hall Nuclear envelope reforming Telophase Mitosis Telophase

10-2 Cell Division Slide 24 of 38 Copyright Pearson Prentice Hall Mitosis Telophase Chromosomes gather at opposite ends of the cell and lose their distinct shape.

10-2 Cell Division Slide 25 of 38 Copyright Pearson Prentice Hall Mitosis A new nuclear envelope forms around each cluster of chromosomes.

10-2 Cell Division Slide 26 of 38 Copyright Pearson Prentice Hall Cytokinesis

10-2 Cell Division Slide 27 of 38 Copyright Pearson Prentice Hall Cytokinesis cytokinesis cytoplasm pinches in half. Each daughter cell has an identical set of duplicate chromosomes.

10-2 Cell Division Slide 28 of 38 Copyright Pearson Prentice Hall Cytokinesis In plants, a structure known as the cell plate forms midway between the divided nuclei. Cell wall Cell plate

10-2 Cell Division Slide 29 of 38 Copyright Pearson Prentice Hall Cytokinesis. A cell wall then begins to appear in the cell plate.

END OF SECTION