Chapter 12: Mitosis - Cell Division  The continuity of life based ...

Chapter 12: Mitosis

The Key Roles of Cell Division

Cell Division  The continuity of life based on the reproduction of cells

• Prokaryotic and Unicellular Eukaryotes

 When they divide, they are reproducing

• Multicellular Organisms

 Develop from a single cell (fertilized) to a two-celled embryo  Function in renewal and repair in fully grown multicellular eukaryotes  Replace cells that die from normal wear and tear or accidents Cell Cycle  The life of a cell from the time its first formed during cell division until its own division into two daughter cells

Concept 12.1: Cell Division Results in Genetically Identical Daughter Cells

 Both prokaryotes and eukaryotes most cell division involves the distribution of identical genetic material (DNA) to two daughter cells

Cellular Organization of the Genetic Material  Genome

• A cells endowment of DNA, it’s genetic information
• Before the cell can divide the genome must be copied or replicated and then the

two copies must be separated to form 2 daughter cells  Chromosomes

• One DNA molecule and associated protein molecules
• Replication and distribution of a lot of DNA is possible because DNA is packaged

in chromosomes

• Eukaryotic Cell

 Has multiple, linear chromosomes which are located in the nucleus

• Prokaryotic Cell

 Has a single, circular chromosome found in the nucleoid (a region not enclosed by a membrane)  Chromatin

• The entire complex of DNA and proteins that is the building material of

chromosomes  Somatic Cells

• All body cells except for the reproductive cells

o Ex) humans: 46 chromosomes, made up of two sets of 23

 Gametes

• Reproductive cells (sperm and eggs)
• Have one set, half as many chromosomes as somatic cells

o Ex) humans: one set of 23 chromosomes

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