12.3 internal/external checkpoint signals Flashcards
1
Q
internal regulation at M phase
A
when cell does not continue to split the sister chromatids until all the kinetochores are attached to spindle
2
Q
external factor
A
-lacking a nutrient
-density dependent inhibition
anchorage dependence
3
Q
growth factors
A
a protein released by certain cells that stimulate other cells to divide
4
Q
example: platelet derived growth factor
A
blood cell fragments, platelets
stimulate fibroblast division
(the wound is healed by fibroblasts)
5
Q
density dependent inhibition
A
external factor
-when crowded cells stop dividing when they touch each other
6
Q
anchorage dependence
A
to divide they must be attached to a substratum
7
Q
cancer cells
A
don’t follow density dependent inhibition nor anchorage dependence so they can divide forever
