Suppose There Is a Small Patch of Membrane from a Mammalian

question 49

Multiple Choice

Suppose there is a small patch of membrane from a mammalian muscle fiber, with a small volume of adjacent cytoplasm and extracellular fluid. Assume that the membrane is most permeable to K⁺. There are 110,000 cations and 110,000 anions in each fluid compartment. The membrane potential results from

• A) only six pairs of ions sitting on the membrane.
• B) the thousands of ions sitting on the membrane.
• C) the overall difference intra- and extra cellular ion concentrations in the volume of cell.
• D) movement of ions across the cell membrane.