Mitosis

Pass genetic information from one generation of cells to the next Made up of DNA and proteins Cells of every organism have a specific number of chromosomes Human somatic (body) cells = 46 chromosomes Chromosomes

Chromosomes Chromosomes are not visible in most cells, because they are spread out throughout the nucleus. At the beginning of cell division, the chromosomes condense and become visible. Before cell division, each chromosome is replicated (copied) to form two identical sister chromatids attached in the center by a centromere.

The Cell Cycle The cell must go through a series of events to grow and divide. During the cell cycle, a cell grows, prepares for division, and divides to form two daughter cells, which each then begin the cycle again.

The Cell Cycle The cell cycle consists of 4 phases: G1: cell growth S: copy chromosomes (DNA replication) G2: preparation for mitosis- more organelles and molecules are produced M: mitosis (nuclear division) & cytokinesis (cytoplasmic division)

Interphase A long period of cell growth in between cell divisions = G1, S, and G2 phases

Mitosis Mitosis is divided into 4 stages: Prophase Metaphase Anaphase The process of nuclear division that forms two identical nuclei with the same number and type of chromosomes as the original. Mitosis is divided into 4 stages: Prophase Metaphase Anaphase Telophase IPMAT http://www.johnkyrk.com/mitosis.html

Prophase Chromosomes become visible Centrioles separate and go to opposite sides of the cell Spindle (fan-like microtubule structure) helps separate the chromosomes Nucleolus disappears and nuclear envelope breaks down

Metaphase Chromosomes line up across the center of the cell Microtubules connent the centromere of each chromosome to the poles of the spindle

Anaphase Sister chromatids separate becoming individual chromosomes Chromosomes continue to move to the poles of the spindle

Telophase Chromosomes spread out; spindles break apart Nuclear envelop re-forms around each cluster of chromosomes Nucleolus becomes visible in each daughter cell Mitosis is complete because the nucleus has divided, but the cell has not divided yet

Cytokinesis The division of the cytoplasm In animal cells, the cell membrane pinches inward separating the cell into two equal parts In PLANT cells, a cell plate forms in between the two nuclei, separates the membrane and forms a cell wall

Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming Go to Section:

Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming Go to Section:

Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming Go to Section:

Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming Go to Section:

Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming Go to Section:

Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming Go to Section: