Mitosis Definition: nuclear division and cytokinesis Functions: tissue growth and repair asexual reproduction (binary & multiple fission)

Cell division requires coordinated division of chromosomes (mitosis)… …and division of the cytoplasm (cytokinesis).

Because DNA stores genetic information and is faithfully replicated, information is passed largely unaltered from cell-to-cell, generation-to-generation.

Proteins and Their Production The Primary Reason for DNA

DNA is Packaged into Chromosomes Two meters DNA fit into a sphere ~ meters in diameter. chromatin duplicated chromosome

The Link Between DNA Replication and Chromosome Duplication

Anatomy of a Chromosome

DNA is Condensed into Visible Chromosomes Only For Brief Periods in the Life of a Cell 95% of the time, chromosomes are like this.

A Karyotype is an Arranged Picture of Chromosomes At Their Most Condensed State A normal human karyotype Boy or girl? Note that almost all chromosomes come in homologous pairs.

Prophase nuclear membrane disintegrates chromatin thickens spindle apparatus appears

Metaphase chromosomes line up on the equatorial plane

Anaphase centromers divide chromatids move toward opposite poles

Telophase nuclear membrane reforms cytokinesis daughter cells

Cytokinesis

In Animal Cells, a Cleavage Furrow Forms and Separates Daughter Cells Cleave furrow in a dividing frog cell.

In plants, a cell plate forms; separating daughter cells during cytokinesis

Stages of Mitosis Prophase– DNA is condensed and packaged Metaphase– “middle stage”; Condensed chromosomes line up along the equatorial plane. Anaphase- Copies of each chromosome move to opposite poles of the cell. Telophase– “end stage”; Nuclear membranes reform around the chromosomes and cytokinesis occurs resulting in two daughter cells.

Cancer is Runaway Mitosis Licentious division - prostate cancer cells during division.