Control of the Cell Cycle

Cyclins Cell cycle is controlled by proteins called cyclins and a set of enzymes that attach to the cyclin and become activated. –The interaction of these molecules is based on conditions within and outside the cell.

Enzyme Production Enzyme production is directed by genes located on chromosomes. –A gene is a segment of DNA that controls the production of a protein. Several enzymes trigger DNA replication at the end of interphase.

Cancer Malignant growth resulting from uncontrolled cell division. –Uncontrolled division can result from failure to produce certain enzymes, overproduction of enzymes, or production of enzymes at the wrong times.

Cancer Cancerous cells form masses of tissue called tumors that deprive normal cells of nutrients. In later stages, cancerous cells enter the circulatory system and spread throughout the body in a process called metastasis. –The result of this process is the formation of new tumors in other organs and organ systems.

Cancer Currently the second leading cause of death in the U.S. (first is heart disease) May affect any tissue in the body. In the U.S., lung, colon, breast, and prostrate cancers are the most prevalent.

Cause of Cancer Currently, scientists consider cancer to be a result of changes in one or more genes that produce substances that are involved in controlling the cell cycle. –These changes are expressed as cancer when something prompts the damaged genes into action.

Cause of Cancer Influenced by both genetic and environmental conditions, such as smoking, exposure to UV radiation, air and water pollution, and diet.

Prevention of Cancer Only current measure of prevention is a healthy lifestyle, including diet.