Section 10.3 (Pg. 286-290): Regulating the Cell Cycle

Controlling Cell Division Uses proteins inside and outside the cell Cyclins Regulate the timing of the cell cycle Internal regulators Allow the cell cycle to proceed only when certain events have occurred

Controlling Cell Division External regulators Can speed up or slow down the cell cycle Growth factors stimulate growth and division of cells Other proteins can cause cells to stop dividing once they fill a space Apoptosis Is controlled cell death Destroys malfunctioning cells Can shape a growing embryo

Too Much Apoptosis

Cancer Cells do not respond to signals that regulate cell growth Cells divide uncontrollably These cells form a tumor Benign tumors do not spread to healthy tissue Malignant tumors take over and destroy healthy tissue Metastasis When cancer cells break off a tumor, travel to other parts of the body, and form more tumors

Causes of Cancer Exposure to toxic chemicals, radiation, and some viruses Results in defective or mutated DNA Damage to genes that control cell growth can cause a tumor Damage to the p53 gene is a common cause of many cancers

Treatment for Cancer Surgery Radiation Chemotherapy Physically remove tumor Radiation Mutate tumor cells’ DNA to make them nonfunctional Chemotherapy Administer chemicals that kill tumor cells or slows their growth Can also interfere with cell division in healthy cells, producing side effects