**Orderly set of steps between eukaryotic cell divisions
Why do Cells Divide?
Some Cells never divide, others divide frequently.
The Cell Cycle
Control of the Cell Cycle
G1 Checkpoint - Check to
see if DNA is damaged
G2 Checkpoint - Check to see if DNA is replicated properly
M Checkpoint - spindle assembly checkpoint, check for alignment of chromosomes
Apoptosis - programmed cell death, if any of the checks fail [Cartoon]
9.2 Mitosis & Cytokinesis
Mitosis - The division of
the nucleus that results in identical complete copies of chromosmes packaged
into two new nuclei
Cytokinesis - The division of the cytoplasm that results in two daughter cells
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Interphase (technically not part of mitosis, but it is included in the cell cycle) Cell is in a resting phase, performing cell functions DNA replicates (copies) Organelles double in number, to prepare for division
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Prophase Spindle forms Centrioles move to opposite poles Chromosomes become visible Nuclear membrane breaks down in prometaphase |
Prometaphase Microtubules of spindle attach to kinetochore on chromosomes
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Metaphase Chromosomes line up along the equator |
Anaphase Centromeres divide Chromatids separate and move to opposite poles |
Telophase Nuclear membrane forms around each group of chromosomes Chromosomes unwind Cytokinesis begins - cell pinches inward and forms two daughter cells. |
**In plant cells, cytokinesis begins
when a new cell wall forms between the two new cells.
**In animal cells, the two new cells pinch and pull apart [see cytokinesis]
Mitosis produces 2 daughter cells
The two daughter cells containt the exact same number of chromosomes as the original parent cell
Daughter cells are DIPLOID
Stem Cells - Reproductive and Therapeutic Cloning
neoplasm: abnormal growth
of cells
benign: non-cancerous
malignant: cancerous
Cancer: cellular growth disorder that results from the mutation of genes that regulate the cell cycle
Cancer cells
