Cell Size Practice Test

A single cell increases its diameter while maintaining the same density of membrane transporters per µm² and the same internal metabolic demand per µm³. Nutrients enter across the plasma membrane by transport proteins. As diameter increases, the cell begins to show lower internal nutrient concentration under the same external conditions. Which explanation best accounts for the decreased nutrient availability in the larger cell?

Two spherical cells are placed in the same solution containing a permeable solute that diffuses across the membrane. Cell Small has radius 2 µm; Cell Large has radius 6 µm. Both begin with the same internal solute concentration, lower than outside. Over the first minute, the internal concentration rises faster in Cell Small. Which explanation best accounts for the faster rise in Cell Small?