Final answer:
If the inside of a cell has an excess of anions compared to the outside, the inside of the cell would be negative relative to the outside due to the presence of negatively charged proteins and anions.
Step-by-step explanation:
The inside of the cell would be negative relative to the outside if the solutions on either side of the membrane have an unequal distribution of charged ions, with the inside having an excess of anions. This is due to the presence of negatively charged proteins and anions inside the cell, creating an electrical gradient across the plasma membrane. The membrane potential favors the movement of positively charged ions into the cell and the movement of negative ions out of the cell, resulting in a negative charge inside the cell.