Ap Bio: Cell Cycle Regulation

the sequential events of the cell cycle are directed by a distinct ________

cell cycle control system

checkpoint

a point in the cell cycle where it stops until it receives a “go-ahead” signal

what happens if a cell receives a go-ahead signal at the G1 checkpoint

it, most likely, will be able to pass all checkpoints and divide

what happens if the cell does not receive the signal

exit cycle and switch to non-dividing state call G0 phase

G0 phase

a non-dividing phase

example of an internal signal

will send a signal to delay anaphase if all spindles are not attached

example of external factors

proteins released by certain cells that stimulate other cells to divide

why can cancer cells divide at will

do not require growth factors

transformation

a normal cell is converted to a cancerous cell

tumors

masses of abnormal cells within otherwise normal tissue

benign tumor

abnormal cells remain at the original site

malignant tumor

when the abnormal cells spread to other parts of the body