Cell Division/Mitosis
Cell division
• Process by which a cell divides into 2 daughter
cells
Why do cells divide?
1. More demand on DNA as the cell grows and
it may not be able to keep up
2. As a cell grows it has trouble moving
nutrients and waste through the cell and out
the cell membrane (Surface area to volume
ratio)
Chromosomes
• Chromosomes are strands of highly organized
DNA
• Must be copied before cell division can occur
• Two identical strands of DNA that are
connected are called sister chromatids
• The area where the chromosomes are
connected is called the centromere
Cell Division

The cell cycle is the life cycle of the cell
• Growth, DNA replication, Prep. For division, division
Interphase

The cell spends most of the cycle in Interphase
• Growth, DNA replication and Prep for Mitosis
Mitosis

Nuclear division
• This is the division of all
the material in the
Nucleus, DNA
• Each new cell that is
formed with have the
same DNA as the
original cell
DNA Replication

Before mitosis can
begin, the DNA must
replicate (make a copy)
Prophase


Nuclear membrane disappears
Chromatin condenses to form chromosomes
Prophase


Nuclear membrane disappears
Chromatin condenses to form chromosomes
Metaphase


Chromosomes line up in the middle
Spindle fibers attach
Anaphase

Sister chromatids are pulled to opposite poles
of the cell
Telophase

DNA starts to unravel to form chromatin
again, nuclear membrane reforms, cell
pinches in at center
Cytokinesis



Not part of mitosis
This is cytoplasmic division
Two new daughter cells are formed, they are
identical (same DNA)