Question

A researcher growing cells in culture observed that the cells always divided once they reached a certain size. When she added more nutrients to the culture medium or adjusted the temperature of the growing chamber, the cells grew at different rates but always divided once they reached a certain size. Which statement explains these observations?a. As they grow, cells require greater and greater quantities of nutrients from the environment, and they must reduce this requirement by dividing.b. The increasing surface area of a cell as it grows larger increases the risk that small molecules that can harm the cell will pass from the environment into the cell interior.c. Efficiency of transport of materials within a cell decreases with size, thus limiting the maximum cell size.d. The cell’s surface area increases faster than its internal volume as it increases in size, and this leads to an inability of the cell to feed itself.

Answer 1

Answer:

The answer is D.

Explanation:

Apart from the signals that cells receive from the DNA for division timing, another factor that determines when cells divide is their size. As the cell grows, it's circumference increases accoring to the formula $2\pi r$ but it's volume follows the area formula mathematically which is $\pi r^{2}$ and this leads to surface area of the cell to increase faster than its volume, leading to problems such as feeding, transportation of materials within the cell etc. So the answer to the example given in the question is D.