Transcript Control of the Cell Cycle

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.