In an experiment, cells grown in a petri dish divided until they formed a thin layer covering the bottom of the dish. When cells were removed from the middle of the dish, the cells bordering the open space began dividing until they had filled the empty space. What does this experiment show?
A) When cells come into contact with other cells, they stop growing.
B) The controls on cell growth and division can be turned on and off.
C) Cell division can be regulated by factors outside of the cell.
D) Cells continue to grow as long as there is adequate space.
E) All answers are valid and correct.

Question

Quizplus · Accepted Answer

This experiment demonstrates several principles of cell behavior: A) Cells exhibit contact inhibition, stopping growth when they contact other cells, indicating a form of growth regulation. B) The ability of cells to resume division in response to the removal of neighboring cells shows that controls on cell growth and division are not fixed but can be modulated. C) The fact that the removal of cells (an external change) triggers cell division suggests that external factors can influence cell behavior. D) The initial spread of the cells across the petri dish until they form a thin layer indicates that cells will continue to grow and divide as long as there is space available, showing a relationship between environmental capacity and cell proliferation.

In an Experiment, Cells Grown in a Petri Dish Divided