A red blood cell placed in ocean water is said to be in what type of solution?

When a red blood cell is placed in ocean water, it is in a hypertonic solution. This means that the concentration of solutes in the ocean water is higher than that inside the red blood cell. As a result, water moves out of the cell through osmosis in an attempt to balance the solute concentrations on both sides of the cell membrane.

In a hypertonic environment, the loss of water from the red blood cell causes it to shrink, a process known as crenation. This response underscores the importance of osmotic balance for proper cell function. Cells in isotonic solutions experience no net movement of water, while hypotonic solutions would lead to water moving into the cell, potentially causing it to swell and even burst. Equilibrium refers to a state where solute concentrations are equal on both sides and does not apply in this context where there is a clear difference in solute concentrations.