A spherical cell is getting 50% of its requirements of some nutrient by diffusion across its membrane. After adhering to a surface, it assumes a new shape - that of a short, fat cylinder (aka a disc). The change in shape does not change the cell's volume or its requirements of this nutrient. Assuming that the permeability of the membrane remains constant, what fraction of the cell's requirement of this nutrient are being met by diffusion after adhering to the surface?
Let the radius of the spherical cell be 50 μm, the height of the cylindrical cell be 5 μm, and assume that diffusion occurs across all surfaces of the cell.