Question

Density-dependent inhibition is a phenomenon in which crowded cells stop dividing at some optimal density and location. This phenomenon involves binding of a cell-surface protein to its counterpart on an adjoining cell's surface. A growth inhibiting signal is sent to both cells, preventing them from dividing. Certain external physical factors can affect this inhibition mechanism.

Select the statement that makes a correct prediction about natural phenomena that could occur during the cell cycle to prevent cell growth.
A) As cells become more numerous, they begin to squeeze against each other, restricting their size and ability to allow cell growth.
B) As cells become more numerous, the protein kinases they produce begin to compete with each other until only one cell has the proteins necessary for growth.
C) As cells become more numerous, the amount of required growth factors and nutrients per cell becomes insufficient to allow for cell growth.
D) As cells become more numerous, more and more of them enter the synthesis part of the cell cycle and duplicate DNA to inhibit cell growth.

Answer 1

The correct prediction about a phenomenon that could occur to prevent cell growth during the cell cycle due to density-dependent inhibition is that as cells proliferate, they may not have enough growth factors and nutrients to support further growth.

C is correct

Step-by-step explanation:

Density-dependent inhibition is a key regulatory mechanism during the cell cycle that ensures cells stop dividing when they become overly crowded. This process involves the interaction of cell-surface proteins between adjacent cells which signal each other to halt division. One accurate prediction about natural phenomena that could prevent cell growth as a result of density-dependent inhibition is: C) As cells become more numerous, the amount of required growth factors and nutrients per cell becomes insufficient to allow for cell growth.

When cells reach a certain density, they may compete for limited resources such as nutrients and growth factors. The scarcity of these essential elements acts as a natural inhibitor of cell proliferation. This is distinct from the process wherein cells enter the synthesis phase of the cell cycle to duplicate DNA, or from the competition among protein kinases, which are not direct consequences of cell crowding. It is important to note that signaling pathways that involve proto-oncogenes and tumor suppressor genes are complex and include not only growth-promoting signals but also signals for inhibition of cell division, demonstrating that multiple factors can impact the cell cycle.

Answer 2

Answer: C) As cells become more numerous, the amount of required growth factors and nutrients per cell becomes insufficient to allow for cell growth.

Step-by-step explanation:

Growth factors are proteins that stimulate cell division.Two of the most important internal factors are kinases and cyclins. In most mammal cells stop dividing once they touch other cells this means that when a cell population reaches a certain density, the amount of required growth factors and nutrients available to each cell becomes insufficient to allow continued cell growth.