Question

The following models show one large cell (A) and four small cells (B).

Which of the following states why one of the models is better for moving more nutrients in and out of the cell?

A. B is better because it has more surface area.
B. A is better because it has less surface area.
C. A is better because it has more volume.
D. B is better because it has more volume.

Answer 1

B is better because it has more surface area.

Answer 2

The surface area to volume ratio is a critical factor in deciding the ability of a cell to take in the nutrients through a passive transport process like diffusion. When the surface area to volume ratio is high, diffusion becomes the best way to take in the nutrients without the expense of energy. When the surface area to volume ratio is low, the cell requires active processes like presence of specialized transport proteins and cytoskeleton to take in the nutrients. In the two models, model A has a lower surface area to volume ratio (
`(6 * a^2)/(a^3)`) while the model B has a greater surface area to volume ratio (
`((6+2) * a^2)/(a^3)`, when the two inner surfaces are included). Hence model B will have better movement of nutrients through diffusion than model A.

A. B is better because it has more surface area.