Cell Cycle Regulation of the…

Mitosis Review You just cleaned the shower, but there is one Serratia marcescens cell left on the shower head. If binary fission takes 30 minutes, how many cells will be there in four hours? How about 24 hours?

Mitosis Review

Checkpoints Cycle pauses until chemical environment is suitable for continuation Cycle pauses until chemical environment is suitable for continuation Mature human cells normally remain here until conditions change (G 0 phase) Mature human cells normally remain here until conditions change (G 0 phase)

G 1 Checkpoint Anchorage dependence Anchorage dependence Cells divide only when anchored to solid surface Cells divide only when anchored to solid surface Density dependence Density dependence Cells divide until a single layer fills entire space Cells divide until a single layer fills entire space Cells divide to fill gaps Cells divide to fill gaps

M Checkpoint Anaphase is delayed until all kinetochores are bound by  tubules Anaphase is delayed until all kinetochores are bound by  tubules Failure to wait for this signal causes… Failure to wait for this signal causes… Nondisjunction Nondisjunction Leads to abnormal chromosome # in offspring cells Leads to abnormal chromosome # in offspring cells

Cancer Cells Lack normal controls of cell cycle Lack normal controls of cell cycle May divide indefinitely until nutrients are depleted (like bacterial cells) May divide indefinitely until nutrients are depleted (like bacterial cells) Transformation Transformation Normal  Cancerous Normal  Cancerous Due to mutation, chemicals, radiation, viruses Due to mutation, chemicals, radiation, viruses

Tumors Proliferation of abnormal cells Proliferation of abnormal cells Benign Benign Localized mass of cells Localized mass of cells Removed by surgery (if necessary) Removed by surgery (if necessary)

Tumors Malignant Malignant Abnormal cells spread to other tissues and hinder function Abnormal cells spread to other tissues and hinder function Metastasis Metastasis Systemic spread through blood or lymph vessels Systemic spread through blood or lymph vessels

Treatments Treatments for metastasized cells target fast-growing cells Treatments for metastasized cells target fast-growing cells Radiation therapy Radiation therapy Chemotherapy Chemotherapy