Question

Describe Na+ regards to the [] and charge of the ion.

a) Positive charge, intracellular concentration
b) Positive charge, extracellular concentration
c) Negative charge, intracellular concentration
d) Negative charge, extracellular concentration

Answer 1

The Na+ ion has a positive charge and is found at a higher concentration in the extracellular fluid, which contributes to the electrochemical gradient across the cell membrane, leading to inward diffusion into the negatively charged interior of cells.

Step-by-step explanation:

The sodium ion (Na+) plays a crucial role in the physiology of cells, particularly in the generation of electrical signals such as action potentials in neurons and muscle cells. A sodium ion is denoted as Na+ because it has a positive charge due to the loss of an electron, resulting in it having one more proton than it has electrons. When we look at the distribution of Na+ in terms of concentration, it is found in a higher concentration in the extracellular fluid compared to the cytoplasm or intracellular fluid.

This difference in concentration contributes to the creation of an electrochemical gradient across the plasma membrane. Cells also exhibit a negative net charge internally due to the presence of negatively charged proteins and other molecules. Thus, both the concentration gradient and the electrical charge of Na+ encourage the diffusion of this ion into the cell.