The Major Reason That the Apparent Diffusion Coefficient of Ca²⁺

Multiple Choice

The major reason that the apparent diffusion coefficient of Ca²⁺ in muscle cell cytosol is much lower than in water is that

A) The cytosol is more viscous than water
B) The re are obstacles to the free movement of Ca²⁺ in the cytosol that aren't present in water
C) Cytosol contains fixed proteins that bind Ca²⁺, slowing its movement
D) The cytosol moves most electrolytes, but not Ca²⁺, around by convection
E) Ca²⁺ causes solidification or gelling of the cytosol