Question

While waiting for a signal to contract, a muscle cell membrane maintains a slightly higher positive charge on which side of the _______ of the membrane? this is possible only because ________ pumps are available to generate this charge difference?

Answer 1

While waiting for a signal to contract, a muscle cell membrane will maintains a slightly higher positive charge on the OUTSIDE of the membrane. This is possible only because SODIUM POTASSIUM ATPASE pumps are available to generate this charge difference. 
The ion concentration difference across the plasma membrane set up electric signals called action potentials which cause a muscle cell to contract.