REGULATING THE CELL CYCLE

Honors Biology Chapter10 Section 3SC B-2.7: Summarize how cell regulation controls & coordinates cell growth & division & allows cells to respond to the environment, and recognize the consequences of uncontrolled cell division

Essential Question

How does cancer happen?

Cell Cultures

Cells in a petri dish with appropriate nutrients will continue to grow until they come in contact with other cells: called

Contact Inhibition

Contact Inhibition

similar controls in body occurs in wound healing

Cell Cycle & Its Regulators

Cell Cycle Regulators: Cyclins regulators are cell proteins

(cyclins) regulate timing of cell cycle in

eukaryotic cells dozens other proteins since

discovered1. Internal Regulators2. External Regulators

Internal Regulators

proteins that respond to events inside the cell

allow cell cycle to proceed once certain processes have been completed inside cell

External Regulators

proteins that respond to events outside cell

direct rate of cell division most important ones:

Growth Factors important in embryonic

development also used in wound healing

Uncontrolled Cell Division Cancer

cancer: disorder in which some of an organisms cells have lost ability to control growth

Cancer cells do not respond to signals that regulate cell division

Cancer Cells have Loss of Contact Inhibition

Causes of Loss of Control??? appears to have many causes:

carcinogenssome affect internal regulators, some external regulators

defect in gene p53

Carcinogens

Nicotine Viruses

Hepatitis Human Papilloma Virus (HPV) Bovine Papilloma Virus Tobacco Virus

Radiation

Cancer Cells

Skin Cells

Stomach Cells

HeLa Cells

Henrietta Lacks died of cervical cancer in Johns Hopkins Hospital, Baltimore, MD in 1950’s

Biopsies of her cervix taken to researchers @Johns Hopkins where they were cultured &they are still growing!

HeLa Cells

used in multiple medical areas: development of Polio Vaccine trip to the moon : What is the effect of

weightlessness on rate of cell growth/division ?

cell cloning gene mapping hybrid cell lines

HeLa Cells

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