The Cell Cycle &
Cell Division
Cell Division—Mitosis Notes Cell Division — process by which a cell divides into 2 new cells • Why do cells need to divide? 1. Living things grow by producing more cells, NOT because each cell increases in size
2. Repair of damaged Cssue 3. If cell gets too big, it cannot get enough nutrients into the cell and wastes out of the cell
The Cell Cycle
http://www.nobel.se/medicine/laureates/2001/press.html
Cell cycle can be divided into stages
• Interphase: G1, S, G2
• Mitosis: Prophase, Metaphase, Anaphase, Telophase & Cytokinesis
Interphase The cell prepares for division and carries out normal cell functions
• G1- primary growth phase
• S- DNA replicates • G2- Cell continues to
grow in size and organelles replicate
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Interphase – S Stage
Two identical copies of DNA
Original DNA
Interphase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
MITOSIS
Mitosis
The process of cell division which results in the production of two daughter cells
from a single parent cell.
The daughter cells are identical to one another and to the original parent
cell.
Prophase The cell prepares for nuclear division
– Packages chromatin (DNA) into visible chromosomes
- Spindle fibers form and nuclear membrane breaks down
Prophase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Metaphase The cell prepares chromosomes for
division – Chromosomes line up
at the center of the cell – Spindle fibers attach to
chromosomes at the centromere
Metaphase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Anaphase The chromosomes divide
– Spindle fibers pull sister chromatids apart to opposite poles of the cell.
Anaphase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Telophase and Cytokinesis The cytoplasm divides
– DNA spreads out – 2 nuclei form
around each set of sister chromatids
– Cytokinesis: Cell membrane pinches in to form the 2 new daughter cells
Telophase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
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Daughter Cells of Mitosis ü Have the same number of
chromosomes as each other and as the parent cell from which they were formed
ü Identical to each other, but smaller than parent cell
ü Must grow in size to become mature cells (G1 of Interphase)