iv. external & internal controls of cell division
TRANSCRIPT
IV. External & Internal Controls of Cell Division
Density Dependent Inhibition
Crowding inhibits cell division why
Anchorage dependence why
Conclusion – 2 reasons cell division is halted
Introduction
Different cells divide at different times and rates: Human skin cells Liver cells Muscle & nerve cells
Evidence from Cell Culture Studies & Growth Factors
Figure 12.18 Method – allowed identification of growth factor
PDGF
Restriction Point (Go)
What and when ResultExamples
Most cells Liver Nerve
VII. Cyclical Changes in Regulatory Proteins Function as a Mitotic Clock
Figure 12.17
Introduction
Controls exist Reason
Control Mechanism by interactions of protein kinases & cyclins
Terms: Protein kinases
Definition Action
Cyclins Definition Function
MPF (maturation Promoting Factor) Definition Composition
Five Steps in Control Process
VIII. Cancer Cells & Cell Division
Don’t respond to controls – 3 waysCharacteristics
Not affected by Can stop Are immortal – HeLa Cells
Consequences of loss of normal controls
Tumor formation Types
Benign Malignant
Can metastasize Definition Reason Metastasis