Presentation on theme: "A Top of Class production. What is the Cell Cycle? Series of events Cell growth Cell division Produce two daughter cells Each new daughter cell."— Presentation transcript:
A Top of Class production
What is the Cell Cycle? Series of events Cell growth Cell division Produce two daughter cells Each new daughter cell will then enter into its own “new” cell cycle Growth and division Prokaryotic vs. Eukaryotic
Prokaryotic Cycle No definable nucleus One DNA loop Enters regular cycle Growth, DNA replication, and cell division Ideal conditions…very quick
When to divide?
Eukaryotic Cycle Cycle has four phases Phase lengths vary Cell type Liver Cells…1-2 a year Bone cells…6-8 weeks Skin cells…6-10 days Brain cells…never Divisions are separated by “in-between” time This is not a resting period Much happens!
The “Cell cycle” accounts for all things that a cell does during its life span… What are those things? 1. G 0 2. G 1 3. G 2 4. S 5. M 6. Cytokinesis
Interphase - “between” phase G1 Phase Cell Growth…majority of size increase new proteins and organelles G = gap phase S Phase DNA Replication…copy of DNA made Ends with twice the amount of DNA S = synthesis
Interphase continued… G2 Phase Cell growth…prep for cell division Shortest phase Materials for division are made During the first three stages the cell grows and prepares for _____________?
M Phase Cell Division Production of two daughter cells Faster than interphase Two stages MITOSIS CYTOKINESIS Both stages can overlap
G 0 The Resting Period A cell will leave the cycle and quit dividing. Temporary Permanent Example… A cell that has reached an end stage of development and will no longer divide Neuron
Restrictive Point Passage through the restriction point is controlled by cyclin dependent kinases (CDKs) Looking for damage If found, the checkpoint uses a signal mechanism stall the cell cycle until repairs are made if repairs cannot be made; then target the cell for destruction via apoptosis
Why do we care about the cell cycle? Cells split Cells grow Making DNA copies We must replace other cells. If we don’t replace we die and have tissue/organ degeneration If a cell is replaced before it needs to be……?