Biology, 10.3, Regulating the Cell Cycle

Apoptosis

A process of programmed cell death. Plays a key role in development by shaping the structure of tissues and organs in plants and animals.

Internal regulators

Allow the cell cycle to proceed only when certain events have occurred in the cell itself (ex. makes sure a cell does not enter mitosis until its chromosomes have replicated). Another regulatory protein prevents a cell from entering anaphase until the spindle fibers have attached to the chromosomes.

What causes cancer?

Defects in genes that regulate cell growth and division.

External regulators

Direct cells to speed up or slow down the cell cycle.

What is cancer?

Disorder in which some of the body's own cells lose the ability to control growth.

Growth factors

External regulatory proteins that stimulate the growth and division of cells.

True or false? Proteins called growth factors regulate the timing of the cell cycle in eukaryotic cells.

False; cyclins

True or false? Cell division speeds up when the healing process nears completion.

False; slows

True or false? Growth factors are external regulatory proteins that slow down the cell cycle.

False; speed up

True or false? Cells tend to continue dividing when they come into contact with other cells.

False; stop

The cell cycle is controlled by both regulatory proteins __________ and outside the cell.

Inside

What are the two basic types of tumors? How are they different?

Malignant rumors are cancerous and invade and destroy healthy tissue in the body. Benign tumors are non cancerous and do not spread into surrounding tissues or to other parts of the body.

Why can can cancer be life threatening?

Rapidly dividing cancer cells take nutrients away from healthy tissues. This leads to a disruption of the proper functioning of body organs that causes illness and may lead to death.

Cyclin

Regulates the cell cycle. Tells a cell when to begin steps of the cell cycle.

True or false? If chromosomes have not attached to spindle fibers during metaphase, an internal regulatory protein will prevent the cell from entering anaphase.

True

True or false? Once apoptosis is triggered, a cell proceeds to self destruct.

True